Merge tag 'for-linus-4.16-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git...
[muen/linux.git] / drivers / net / xen-netfront.c
1 /*
2  * Virtual network driver for conversing with remote driver backends.
3  *
4  * Copyright (c) 2002-2005, K A Fraser
5  * Copyright (c) 2005, XenSource Ltd
6  *
7  * This program is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU General Public License version 2
9  * as published by the Free Software Foundation; or, when distributed
10  * separately from the Linux kernel or incorporated into other
11  * software packages, subject to the following license:
12  *
13  * Permission is hereby granted, free of charge, to any person obtaining a copy
14  * of this source file (the "Software"), to deal in the Software without
15  * restriction, including without limitation the rights to use, copy, modify,
16  * merge, publish, distribute, sublicense, and/or sell copies of the Software,
17  * and to permit persons to whom the Software is furnished to do so, subject to
18  * the following conditions:
19  *
20  * The above copyright notice and this permission notice shall be included in
21  * all copies or substantial portions of the Software.
22  *
23  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
24  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
25  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
26  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
27  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
28  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
29  * IN THE SOFTWARE.
30  */
31
32 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
33
34 #include <linux/module.h>
35 #include <linux/kernel.h>
36 #include <linux/netdevice.h>
37 #include <linux/etherdevice.h>
38 #include <linux/skbuff.h>
39 #include <linux/ethtool.h>
40 #include <linux/if_ether.h>
41 #include <net/tcp.h>
42 #include <linux/udp.h>
43 #include <linux/moduleparam.h>
44 #include <linux/mm.h>
45 #include <linux/slab.h>
46 #include <net/ip.h>
47
48 #include <xen/xen.h>
49 #include <xen/xenbus.h>
50 #include <xen/events.h>
51 #include <xen/page.h>
52 #include <xen/platform_pci.h>
53 #include <xen/grant_table.h>
54
55 #include <xen/interface/io/netif.h>
56 #include <xen/interface/memory.h>
57 #include <xen/interface/grant_table.h>
58
59 /* Module parameters */
60 #define MAX_QUEUES_DEFAULT 8
61 static unsigned int xennet_max_queues;
62 module_param_named(max_queues, xennet_max_queues, uint, 0644);
63 MODULE_PARM_DESC(max_queues,
64                  "Maximum number of queues per virtual interface");
65
66 static const struct ethtool_ops xennet_ethtool_ops;
67
68 struct netfront_cb {
69         int pull_to;
70 };
71
72 #define NETFRONT_SKB_CB(skb)    ((struct netfront_cb *)((skb)->cb))
73
74 #define RX_COPY_THRESHOLD 256
75
76 #define GRANT_INVALID_REF       0
77
78 #define NET_TX_RING_SIZE __CONST_RING_SIZE(xen_netif_tx, XEN_PAGE_SIZE)
79 #define NET_RX_RING_SIZE __CONST_RING_SIZE(xen_netif_rx, XEN_PAGE_SIZE)
80
81 /* Minimum number of Rx slots (includes slot for GSO metadata). */
82 #define NET_RX_SLOTS_MIN (XEN_NETIF_NR_SLOTS_MIN + 1)
83
84 /* Queue name is interface name with "-qNNN" appended */
85 #define QUEUE_NAME_SIZE (IFNAMSIZ + 6)
86
87 /* IRQ name is queue name with "-tx" or "-rx" appended */
88 #define IRQ_NAME_SIZE (QUEUE_NAME_SIZE + 3)
89
90 static DECLARE_WAIT_QUEUE_HEAD(module_unload_q);
91
92 struct netfront_stats {
93         u64                     packets;
94         u64                     bytes;
95         struct u64_stats_sync   syncp;
96 };
97
98 struct netfront_info;
99
100 struct netfront_queue {
101         unsigned int id; /* Queue ID, 0-based */
102         char name[QUEUE_NAME_SIZE]; /* DEVNAME-qN */
103         struct netfront_info *info;
104
105         struct napi_struct napi;
106
107         /* Split event channels support, tx_* == rx_* when using
108          * single event channel.
109          */
110         unsigned int tx_evtchn, rx_evtchn;
111         unsigned int tx_irq, rx_irq;
112         /* Only used when split event channels support is enabled */
113         char tx_irq_name[IRQ_NAME_SIZE]; /* DEVNAME-qN-tx */
114         char rx_irq_name[IRQ_NAME_SIZE]; /* DEVNAME-qN-rx */
115
116         spinlock_t   tx_lock;
117         struct xen_netif_tx_front_ring tx;
118         int tx_ring_ref;
119
120         /*
121          * {tx,rx}_skbs store outstanding skbuffs. Free tx_skb entries
122          * are linked from tx_skb_freelist through skb_entry.link.
123          *
124          *  NB. Freelist index entries are always going to be less than
125          *  PAGE_OFFSET, whereas pointers to skbs will always be equal or
126          *  greater than PAGE_OFFSET: we use this property to distinguish
127          *  them.
128          */
129         union skb_entry {
130                 struct sk_buff *skb;
131                 unsigned long link;
132         } tx_skbs[NET_TX_RING_SIZE];
133         grant_ref_t gref_tx_head;
134         grant_ref_t grant_tx_ref[NET_TX_RING_SIZE];
135         struct page *grant_tx_page[NET_TX_RING_SIZE];
136         unsigned tx_skb_freelist;
137
138         spinlock_t   rx_lock ____cacheline_aligned_in_smp;
139         struct xen_netif_rx_front_ring rx;
140         int rx_ring_ref;
141
142         struct timer_list rx_refill_timer;
143
144         struct sk_buff *rx_skbs[NET_RX_RING_SIZE];
145         grant_ref_t gref_rx_head;
146         grant_ref_t grant_rx_ref[NET_RX_RING_SIZE];
147 };
148
149 struct netfront_info {
150         struct list_head list;
151         struct net_device *netdev;
152
153         struct xenbus_device *xbdev;
154
155         /* Multi-queue support */
156         struct netfront_queue *queues;
157
158         /* Statistics */
159         struct netfront_stats __percpu *rx_stats;
160         struct netfront_stats __percpu *tx_stats;
161
162         atomic_t rx_gso_checksum_fixup;
163 };
164
165 struct netfront_rx_info {
166         struct xen_netif_rx_response rx;
167         struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX - 1];
168 };
169
170 static void skb_entry_set_link(union skb_entry *list, unsigned short id)
171 {
172         list->link = id;
173 }
174
175 static int skb_entry_is_link(const union skb_entry *list)
176 {
177         BUILD_BUG_ON(sizeof(list->skb) != sizeof(list->link));
178         return (unsigned long)list->skb < PAGE_OFFSET;
179 }
180
181 /*
182  * Access macros for acquiring freeing slots in tx_skbs[].
183  */
184
185 static void add_id_to_freelist(unsigned *head, union skb_entry *list,
186                                unsigned short id)
187 {
188         skb_entry_set_link(&list[id], *head);
189         *head = id;
190 }
191
192 static unsigned short get_id_from_freelist(unsigned *head,
193                                            union skb_entry *list)
194 {
195         unsigned int id = *head;
196         *head = list[id].link;
197         return id;
198 }
199
200 static int xennet_rxidx(RING_IDX idx)
201 {
202         return idx & (NET_RX_RING_SIZE - 1);
203 }
204
205 static struct sk_buff *xennet_get_rx_skb(struct netfront_queue *queue,
206                                          RING_IDX ri)
207 {
208         int i = xennet_rxidx(ri);
209         struct sk_buff *skb = queue->rx_skbs[i];
210         queue->rx_skbs[i] = NULL;
211         return skb;
212 }
213
214 static grant_ref_t xennet_get_rx_ref(struct netfront_queue *queue,
215                                             RING_IDX ri)
216 {
217         int i = xennet_rxidx(ri);
218         grant_ref_t ref = queue->grant_rx_ref[i];
219         queue->grant_rx_ref[i] = GRANT_INVALID_REF;
220         return ref;
221 }
222
223 #ifdef CONFIG_SYSFS
224 static const struct attribute_group xennet_dev_group;
225 #endif
226
227 static bool xennet_can_sg(struct net_device *dev)
228 {
229         return dev->features & NETIF_F_SG;
230 }
231
232
233 static void rx_refill_timeout(struct timer_list *t)
234 {
235         struct netfront_queue *queue = from_timer(queue, t, rx_refill_timer);
236         napi_schedule(&queue->napi);
237 }
238
239 static int netfront_tx_slot_available(struct netfront_queue *queue)
240 {
241         return (queue->tx.req_prod_pvt - queue->tx.rsp_cons) <
242                 (NET_TX_RING_SIZE - MAX_SKB_FRAGS - 2);
243 }
244
245 static void xennet_maybe_wake_tx(struct netfront_queue *queue)
246 {
247         struct net_device *dev = queue->info->netdev;
248         struct netdev_queue *dev_queue = netdev_get_tx_queue(dev, queue->id);
249
250         if (unlikely(netif_tx_queue_stopped(dev_queue)) &&
251             netfront_tx_slot_available(queue) &&
252             likely(netif_running(dev)))
253                 netif_tx_wake_queue(netdev_get_tx_queue(dev, queue->id));
254 }
255
256
257 static struct sk_buff *xennet_alloc_one_rx_buffer(struct netfront_queue *queue)
258 {
259         struct sk_buff *skb;
260         struct page *page;
261
262         skb = __netdev_alloc_skb(queue->info->netdev,
263                                  RX_COPY_THRESHOLD + NET_IP_ALIGN,
264                                  GFP_ATOMIC | __GFP_NOWARN);
265         if (unlikely(!skb))
266                 return NULL;
267
268         page = alloc_page(GFP_ATOMIC | __GFP_NOWARN);
269         if (!page) {
270                 kfree_skb(skb);
271                 return NULL;
272         }
273         skb_add_rx_frag(skb, 0, page, 0, 0, PAGE_SIZE);
274
275         /* Align ip header to a 16 bytes boundary */
276         skb_reserve(skb, NET_IP_ALIGN);
277         skb->dev = queue->info->netdev;
278
279         return skb;
280 }
281
282
283 static void xennet_alloc_rx_buffers(struct netfront_queue *queue)
284 {
285         RING_IDX req_prod = queue->rx.req_prod_pvt;
286         int notify;
287         int err = 0;
288
289         if (unlikely(!netif_carrier_ok(queue->info->netdev)))
290                 return;
291
292         for (req_prod = queue->rx.req_prod_pvt;
293              req_prod - queue->rx.rsp_cons < NET_RX_RING_SIZE;
294              req_prod++) {
295                 struct sk_buff *skb;
296                 unsigned short id;
297                 grant_ref_t ref;
298                 struct page *page;
299                 struct xen_netif_rx_request *req;
300
301                 skb = xennet_alloc_one_rx_buffer(queue);
302                 if (!skb) {
303                         err = -ENOMEM;
304                         break;
305                 }
306
307                 id = xennet_rxidx(req_prod);
308
309                 BUG_ON(queue->rx_skbs[id]);
310                 queue->rx_skbs[id] = skb;
311
312                 ref = gnttab_claim_grant_reference(&queue->gref_rx_head);
313                 WARN_ON_ONCE(IS_ERR_VALUE((unsigned long)(int)ref));
314                 queue->grant_rx_ref[id] = ref;
315
316                 page = skb_frag_page(&skb_shinfo(skb)->frags[0]);
317
318                 req = RING_GET_REQUEST(&queue->rx, req_prod);
319                 gnttab_page_grant_foreign_access_ref_one(ref,
320                                                          queue->info->xbdev->otherend_id,
321                                                          page,
322                                                          0);
323                 req->id = id;
324                 req->gref = ref;
325         }
326
327         queue->rx.req_prod_pvt = req_prod;
328
329         /* Try again later if there are not enough requests or skb allocation
330          * failed.
331          * Enough requests is quantified as the sum of newly created slots and
332          * the unconsumed slots at the backend.
333          */
334         if (req_prod - queue->rx.rsp_cons < NET_RX_SLOTS_MIN ||
335             unlikely(err)) {
336                 mod_timer(&queue->rx_refill_timer, jiffies + (HZ/10));
337                 return;
338         }
339
340         wmb();          /* barrier so backend seens requests */
341
342         RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&queue->rx, notify);
343         if (notify)
344                 notify_remote_via_irq(queue->rx_irq);
345 }
346
347 static int xennet_open(struct net_device *dev)
348 {
349         struct netfront_info *np = netdev_priv(dev);
350         unsigned int num_queues = dev->real_num_tx_queues;
351         unsigned int i = 0;
352         struct netfront_queue *queue = NULL;
353
354         if (!np->queues)
355                 return -ENODEV;
356
357         for (i = 0; i < num_queues; ++i) {
358                 queue = &np->queues[i];
359                 napi_enable(&queue->napi);
360
361                 spin_lock_bh(&queue->rx_lock);
362                 if (netif_carrier_ok(dev)) {
363                         xennet_alloc_rx_buffers(queue);
364                         queue->rx.sring->rsp_event = queue->rx.rsp_cons + 1;
365                         if (RING_HAS_UNCONSUMED_RESPONSES(&queue->rx))
366                                 napi_schedule(&queue->napi);
367                 }
368                 spin_unlock_bh(&queue->rx_lock);
369         }
370
371         netif_tx_start_all_queues(dev);
372
373         return 0;
374 }
375
376 static void xennet_tx_buf_gc(struct netfront_queue *queue)
377 {
378         RING_IDX cons, prod;
379         unsigned short id;
380         struct sk_buff *skb;
381         bool more_to_do;
382
383         BUG_ON(!netif_carrier_ok(queue->info->netdev));
384
385         do {
386                 prod = queue->tx.sring->rsp_prod;
387                 rmb(); /* Ensure we see responses up to 'rp'. */
388
389                 for (cons = queue->tx.rsp_cons; cons != prod; cons++) {
390                         struct xen_netif_tx_response *txrsp;
391
392                         txrsp = RING_GET_RESPONSE(&queue->tx, cons);
393                         if (txrsp->status == XEN_NETIF_RSP_NULL)
394                                 continue;
395
396                         id  = txrsp->id;
397                         skb = queue->tx_skbs[id].skb;
398                         if (unlikely(gnttab_query_foreign_access(
399                                 queue->grant_tx_ref[id]) != 0)) {
400                                 pr_alert("%s: warning -- grant still in use by backend domain\n",
401                                          __func__);
402                                 BUG();
403                         }
404                         gnttab_end_foreign_access_ref(
405                                 queue->grant_tx_ref[id], GNTMAP_readonly);
406                         gnttab_release_grant_reference(
407                                 &queue->gref_tx_head, queue->grant_tx_ref[id]);
408                         queue->grant_tx_ref[id] = GRANT_INVALID_REF;
409                         queue->grant_tx_page[id] = NULL;
410                         add_id_to_freelist(&queue->tx_skb_freelist, queue->tx_skbs, id);
411                         dev_kfree_skb_irq(skb);
412                 }
413
414                 queue->tx.rsp_cons = prod;
415
416                 RING_FINAL_CHECK_FOR_RESPONSES(&queue->tx, more_to_do);
417         } while (more_to_do);
418
419         xennet_maybe_wake_tx(queue);
420 }
421
422 struct xennet_gnttab_make_txreq {
423         struct netfront_queue *queue;
424         struct sk_buff *skb;
425         struct page *page;
426         struct xen_netif_tx_request *tx; /* Last request */
427         unsigned int size;
428 };
429
430 static void xennet_tx_setup_grant(unsigned long gfn, unsigned int offset,
431                                   unsigned int len, void *data)
432 {
433         struct xennet_gnttab_make_txreq *info = data;
434         unsigned int id;
435         struct xen_netif_tx_request *tx;
436         grant_ref_t ref;
437         /* convenient aliases */
438         struct page *page = info->page;
439         struct netfront_queue *queue = info->queue;
440         struct sk_buff *skb = info->skb;
441
442         id = get_id_from_freelist(&queue->tx_skb_freelist, queue->tx_skbs);
443         tx = RING_GET_REQUEST(&queue->tx, queue->tx.req_prod_pvt++);
444         ref = gnttab_claim_grant_reference(&queue->gref_tx_head);
445         WARN_ON_ONCE(IS_ERR_VALUE((unsigned long)(int)ref));
446
447         gnttab_grant_foreign_access_ref(ref, queue->info->xbdev->otherend_id,
448                                         gfn, GNTMAP_readonly);
449
450         queue->tx_skbs[id].skb = skb;
451         queue->grant_tx_page[id] = page;
452         queue->grant_tx_ref[id] = ref;
453
454         tx->id = id;
455         tx->gref = ref;
456         tx->offset = offset;
457         tx->size = len;
458         tx->flags = 0;
459
460         info->tx = tx;
461         info->size += tx->size;
462 }
463
464 static struct xen_netif_tx_request *xennet_make_first_txreq(
465         struct netfront_queue *queue, struct sk_buff *skb,
466         struct page *page, unsigned int offset, unsigned int len)
467 {
468         struct xennet_gnttab_make_txreq info = {
469                 .queue = queue,
470                 .skb = skb,
471                 .page = page,
472                 .size = 0,
473         };
474
475         gnttab_for_one_grant(page, offset, len, xennet_tx_setup_grant, &info);
476
477         return info.tx;
478 }
479
480 static void xennet_make_one_txreq(unsigned long gfn, unsigned int offset,
481                                   unsigned int len, void *data)
482 {
483         struct xennet_gnttab_make_txreq *info = data;
484
485         info->tx->flags |= XEN_NETTXF_more_data;
486         skb_get(info->skb);
487         xennet_tx_setup_grant(gfn, offset, len, data);
488 }
489
490 static struct xen_netif_tx_request *xennet_make_txreqs(
491         struct netfront_queue *queue, struct xen_netif_tx_request *tx,
492         struct sk_buff *skb, struct page *page,
493         unsigned int offset, unsigned int len)
494 {
495         struct xennet_gnttab_make_txreq info = {
496                 .queue = queue,
497                 .skb = skb,
498                 .tx = tx,
499         };
500
501         /* Skip unused frames from start of page */
502         page += offset >> PAGE_SHIFT;
503         offset &= ~PAGE_MASK;
504
505         while (len) {
506                 info.page = page;
507                 info.size = 0;
508
509                 gnttab_foreach_grant_in_range(page, offset, len,
510                                               xennet_make_one_txreq,
511                                               &info);
512
513                 page++;
514                 offset = 0;
515                 len -= info.size;
516         }
517
518         return info.tx;
519 }
520
521 /*
522  * Count how many ring slots are required to send this skb. Each frag
523  * might be a compound page.
524  */
525 static int xennet_count_skb_slots(struct sk_buff *skb)
526 {
527         int i, frags = skb_shinfo(skb)->nr_frags;
528         int slots;
529
530         slots = gnttab_count_grant(offset_in_page(skb->data),
531                                    skb_headlen(skb));
532
533         for (i = 0; i < frags; i++) {
534                 skb_frag_t *frag = skb_shinfo(skb)->frags + i;
535                 unsigned long size = skb_frag_size(frag);
536                 unsigned long offset = frag->page_offset;
537
538                 /* Skip unused frames from start of page */
539                 offset &= ~PAGE_MASK;
540
541                 slots += gnttab_count_grant(offset, size);
542         }
543
544         return slots;
545 }
546
547 static u16 xennet_select_queue(struct net_device *dev, struct sk_buff *skb,
548                                void *accel_priv, select_queue_fallback_t fallback)
549 {
550         unsigned int num_queues = dev->real_num_tx_queues;
551         u32 hash;
552         u16 queue_idx;
553
554         /* First, check if there is only one queue */
555         if (num_queues == 1) {
556                 queue_idx = 0;
557         } else {
558                 hash = skb_get_hash(skb);
559                 queue_idx = hash % num_queues;
560         }
561
562         return queue_idx;
563 }
564
565 #define MAX_XEN_SKB_FRAGS (65536 / XEN_PAGE_SIZE + 1)
566
567 static int xennet_start_xmit(struct sk_buff *skb, struct net_device *dev)
568 {
569         struct netfront_info *np = netdev_priv(dev);
570         struct netfront_stats *tx_stats = this_cpu_ptr(np->tx_stats);
571         struct xen_netif_tx_request *tx, *first_tx;
572         unsigned int i;
573         int notify;
574         int slots;
575         struct page *page;
576         unsigned int offset;
577         unsigned int len;
578         unsigned long flags;
579         struct netfront_queue *queue = NULL;
580         unsigned int num_queues = dev->real_num_tx_queues;
581         u16 queue_index;
582         struct sk_buff *nskb;
583
584         /* Drop the packet if no queues are set up */
585         if (num_queues < 1)
586                 goto drop;
587         /* Determine which queue to transmit this SKB on */
588         queue_index = skb_get_queue_mapping(skb);
589         queue = &np->queues[queue_index];
590
591         /* If skb->len is too big for wire format, drop skb and alert
592          * user about misconfiguration.
593          */
594         if (unlikely(skb->len > XEN_NETIF_MAX_TX_SIZE)) {
595                 net_alert_ratelimited(
596                         "xennet: skb->len = %u, too big for wire format\n",
597                         skb->len);
598                 goto drop;
599         }
600
601         slots = xennet_count_skb_slots(skb);
602         if (unlikely(slots > MAX_XEN_SKB_FRAGS + 1)) {
603                 net_dbg_ratelimited("xennet: skb rides the rocket: %d slots, %d bytes\n",
604                                     slots, skb->len);
605                 if (skb_linearize(skb))
606                         goto drop;
607         }
608
609         page = virt_to_page(skb->data);
610         offset = offset_in_page(skb->data);
611
612         /* The first req should be at least ETH_HLEN size or the packet will be
613          * dropped by netback.
614          */
615         if (unlikely(PAGE_SIZE - offset < ETH_HLEN)) {
616                 nskb = skb_copy(skb, GFP_ATOMIC);
617                 if (!nskb)
618                         goto drop;
619                 dev_consume_skb_any(skb);
620                 skb = nskb;
621                 page = virt_to_page(skb->data);
622                 offset = offset_in_page(skb->data);
623         }
624
625         len = skb_headlen(skb);
626
627         spin_lock_irqsave(&queue->tx_lock, flags);
628
629         if (unlikely(!netif_carrier_ok(dev) ||
630                      (slots > 1 && !xennet_can_sg(dev)) ||
631                      netif_needs_gso(skb, netif_skb_features(skb)))) {
632                 spin_unlock_irqrestore(&queue->tx_lock, flags);
633                 goto drop;
634         }
635
636         /* First request for the linear area. */
637         first_tx = tx = xennet_make_first_txreq(queue, skb,
638                                                 page, offset, len);
639         offset += tx->size;
640         if (offset == PAGE_SIZE) {
641                 page++;
642                 offset = 0;
643         }
644         len -= tx->size;
645
646         if (skb->ip_summed == CHECKSUM_PARTIAL)
647                 /* local packet? */
648                 tx->flags |= XEN_NETTXF_csum_blank | XEN_NETTXF_data_validated;
649         else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
650                 /* remote but checksummed. */
651                 tx->flags |= XEN_NETTXF_data_validated;
652
653         /* Optional extra info after the first request. */
654         if (skb_shinfo(skb)->gso_size) {
655                 struct xen_netif_extra_info *gso;
656
657                 gso = (struct xen_netif_extra_info *)
658                         RING_GET_REQUEST(&queue->tx, queue->tx.req_prod_pvt++);
659
660                 tx->flags |= XEN_NETTXF_extra_info;
661
662                 gso->u.gso.size = skb_shinfo(skb)->gso_size;
663                 gso->u.gso.type = (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6) ?
664                         XEN_NETIF_GSO_TYPE_TCPV6 :
665                         XEN_NETIF_GSO_TYPE_TCPV4;
666                 gso->u.gso.pad = 0;
667                 gso->u.gso.features = 0;
668
669                 gso->type = XEN_NETIF_EXTRA_TYPE_GSO;
670                 gso->flags = 0;
671         }
672
673         /* Requests for the rest of the linear area. */
674         tx = xennet_make_txreqs(queue, tx, skb, page, offset, len);
675
676         /* Requests for all the frags. */
677         for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
678                 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
679                 tx = xennet_make_txreqs(queue, tx, skb,
680                                         skb_frag_page(frag), frag->page_offset,
681                                         skb_frag_size(frag));
682         }
683
684         /* First request has the packet length. */
685         first_tx->size = skb->len;
686
687         RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&queue->tx, notify);
688         if (notify)
689                 notify_remote_via_irq(queue->tx_irq);
690
691         u64_stats_update_begin(&tx_stats->syncp);
692         tx_stats->bytes += skb->len;
693         tx_stats->packets++;
694         u64_stats_update_end(&tx_stats->syncp);
695
696         /* Note: It is not safe to access skb after xennet_tx_buf_gc()! */
697         xennet_tx_buf_gc(queue);
698
699         if (!netfront_tx_slot_available(queue))
700                 netif_tx_stop_queue(netdev_get_tx_queue(dev, queue->id));
701
702         spin_unlock_irqrestore(&queue->tx_lock, flags);
703
704         return NETDEV_TX_OK;
705
706  drop:
707         dev->stats.tx_dropped++;
708         dev_kfree_skb_any(skb);
709         return NETDEV_TX_OK;
710 }
711
712 static int xennet_close(struct net_device *dev)
713 {
714         struct netfront_info *np = netdev_priv(dev);
715         unsigned int num_queues = dev->real_num_tx_queues;
716         unsigned int i;
717         struct netfront_queue *queue;
718         netif_tx_stop_all_queues(np->netdev);
719         for (i = 0; i < num_queues; ++i) {
720                 queue = &np->queues[i];
721                 napi_disable(&queue->napi);
722         }
723         return 0;
724 }
725
726 static void xennet_move_rx_slot(struct netfront_queue *queue, struct sk_buff *skb,
727                                 grant_ref_t ref)
728 {
729         int new = xennet_rxidx(queue->rx.req_prod_pvt);
730
731         BUG_ON(queue->rx_skbs[new]);
732         queue->rx_skbs[new] = skb;
733         queue->grant_rx_ref[new] = ref;
734         RING_GET_REQUEST(&queue->rx, queue->rx.req_prod_pvt)->id = new;
735         RING_GET_REQUEST(&queue->rx, queue->rx.req_prod_pvt)->gref = ref;
736         queue->rx.req_prod_pvt++;
737 }
738
739 static int xennet_get_extras(struct netfront_queue *queue,
740                              struct xen_netif_extra_info *extras,
741                              RING_IDX rp)
742
743 {
744         struct xen_netif_extra_info *extra;
745         struct device *dev = &queue->info->netdev->dev;
746         RING_IDX cons = queue->rx.rsp_cons;
747         int err = 0;
748
749         do {
750                 struct sk_buff *skb;
751                 grant_ref_t ref;
752
753                 if (unlikely(cons + 1 == rp)) {
754                         if (net_ratelimit())
755                                 dev_warn(dev, "Missing extra info\n");
756                         err = -EBADR;
757                         break;
758                 }
759
760                 extra = (struct xen_netif_extra_info *)
761                         RING_GET_RESPONSE(&queue->rx, ++cons);
762
763                 if (unlikely(!extra->type ||
764                              extra->type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
765                         if (net_ratelimit())
766                                 dev_warn(dev, "Invalid extra type: %d\n",
767                                         extra->type);
768                         err = -EINVAL;
769                 } else {
770                         memcpy(&extras[extra->type - 1], extra,
771                                sizeof(*extra));
772                 }
773
774                 skb = xennet_get_rx_skb(queue, cons);
775                 ref = xennet_get_rx_ref(queue, cons);
776                 xennet_move_rx_slot(queue, skb, ref);
777         } while (extra->flags & XEN_NETIF_EXTRA_FLAG_MORE);
778
779         queue->rx.rsp_cons = cons;
780         return err;
781 }
782
783 static int xennet_get_responses(struct netfront_queue *queue,
784                                 struct netfront_rx_info *rinfo, RING_IDX rp,
785                                 struct sk_buff_head *list)
786 {
787         struct xen_netif_rx_response *rx = &rinfo->rx;
788         struct xen_netif_extra_info *extras = rinfo->extras;
789         struct device *dev = &queue->info->netdev->dev;
790         RING_IDX cons = queue->rx.rsp_cons;
791         struct sk_buff *skb = xennet_get_rx_skb(queue, cons);
792         grant_ref_t ref = xennet_get_rx_ref(queue, cons);
793         int max = MAX_SKB_FRAGS + (rx->status <= RX_COPY_THRESHOLD);
794         int slots = 1;
795         int err = 0;
796         unsigned long ret;
797
798         if (rx->flags & XEN_NETRXF_extra_info) {
799                 err = xennet_get_extras(queue, extras, rp);
800                 cons = queue->rx.rsp_cons;
801         }
802
803         for (;;) {
804                 if (unlikely(rx->status < 0 ||
805                              rx->offset + rx->status > XEN_PAGE_SIZE)) {
806                         if (net_ratelimit())
807                                 dev_warn(dev, "rx->offset: %u, size: %d\n",
808                                          rx->offset, rx->status);
809                         xennet_move_rx_slot(queue, skb, ref);
810                         err = -EINVAL;
811                         goto next;
812                 }
813
814                 /*
815                  * This definitely indicates a bug, either in this driver or in
816                  * the backend driver. In future this should flag the bad
817                  * situation to the system controller to reboot the backend.
818                  */
819                 if (ref == GRANT_INVALID_REF) {
820                         if (net_ratelimit())
821                                 dev_warn(dev, "Bad rx response id %d.\n",
822                                          rx->id);
823                         err = -EINVAL;
824                         goto next;
825                 }
826
827                 ret = gnttab_end_foreign_access_ref(ref, 0);
828                 BUG_ON(!ret);
829
830                 gnttab_release_grant_reference(&queue->gref_rx_head, ref);
831
832                 __skb_queue_tail(list, skb);
833
834 next:
835                 if (!(rx->flags & XEN_NETRXF_more_data))
836                         break;
837
838                 if (cons + slots == rp) {
839                         if (net_ratelimit())
840                                 dev_warn(dev, "Need more slots\n");
841                         err = -ENOENT;
842                         break;
843                 }
844
845                 rx = RING_GET_RESPONSE(&queue->rx, cons + slots);
846                 skb = xennet_get_rx_skb(queue, cons + slots);
847                 ref = xennet_get_rx_ref(queue, cons + slots);
848                 slots++;
849         }
850
851         if (unlikely(slots > max)) {
852                 if (net_ratelimit())
853                         dev_warn(dev, "Too many slots\n");
854                 err = -E2BIG;
855         }
856
857         if (unlikely(err))
858                 queue->rx.rsp_cons = cons + slots;
859
860         return err;
861 }
862
863 static int xennet_set_skb_gso(struct sk_buff *skb,
864                               struct xen_netif_extra_info *gso)
865 {
866         if (!gso->u.gso.size) {
867                 if (net_ratelimit())
868                         pr_warn("GSO size must not be zero\n");
869                 return -EINVAL;
870         }
871
872         if (gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV4 &&
873             gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV6) {
874                 if (net_ratelimit())
875                         pr_warn("Bad GSO type %d\n", gso->u.gso.type);
876                 return -EINVAL;
877         }
878
879         skb_shinfo(skb)->gso_size = gso->u.gso.size;
880         skb_shinfo(skb)->gso_type =
881                 (gso->u.gso.type == XEN_NETIF_GSO_TYPE_TCPV4) ?
882                 SKB_GSO_TCPV4 :
883                 SKB_GSO_TCPV6;
884
885         /* Header must be checked, and gso_segs computed. */
886         skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
887         skb_shinfo(skb)->gso_segs = 0;
888
889         return 0;
890 }
891
892 static RING_IDX xennet_fill_frags(struct netfront_queue *queue,
893                                   struct sk_buff *skb,
894                                   struct sk_buff_head *list)
895 {
896         struct skb_shared_info *shinfo = skb_shinfo(skb);
897         RING_IDX cons = queue->rx.rsp_cons;
898         struct sk_buff *nskb;
899
900         while ((nskb = __skb_dequeue(list))) {
901                 struct xen_netif_rx_response *rx =
902                         RING_GET_RESPONSE(&queue->rx, ++cons);
903                 skb_frag_t *nfrag = &skb_shinfo(nskb)->frags[0];
904
905                 if (shinfo->nr_frags == MAX_SKB_FRAGS) {
906                         unsigned int pull_to = NETFRONT_SKB_CB(skb)->pull_to;
907
908                         BUG_ON(pull_to <= skb_headlen(skb));
909                         __pskb_pull_tail(skb, pull_to - skb_headlen(skb));
910                 }
911                 BUG_ON(shinfo->nr_frags >= MAX_SKB_FRAGS);
912
913                 skb_add_rx_frag(skb, shinfo->nr_frags, skb_frag_page(nfrag),
914                                 rx->offset, rx->status, PAGE_SIZE);
915
916                 skb_shinfo(nskb)->nr_frags = 0;
917                 kfree_skb(nskb);
918         }
919
920         return cons;
921 }
922
923 static int checksum_setup(struct net_device *dev, struct sk_buff *skb)
924 {
925         bool recalculate_partial_csum = false;
926
927         /*
928          * A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
929          * peers can fail to set NETRXF_csum_blank when sending a GSO
930          * frame. In this case force the SKB to CHECKSUM_PARTIAL and
931          * recalculate the partial checksum.
932          */
933         if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
934                 struct netfront_info *np = netdev_priv(dev);
935                 atomic_inc(&np->rx_gso_checksum_fixup);
936                 skb->ip_summed = CHECKSUM_PARTIAL;
937                 recalculate_partial_csum = true;
938         }
939
940         /* A non-CHECKSUM_PARTIAL SKB does not require setup. */
941         if (skb->ip_summed != CHECKSUM_PARTIAL)
942                 return 0;
943
944         return skb_checksum_setup(skb, recalculate_partial_csum);
945 }
946
947 static int handle_incoming_queue(struct netfront_queue *queue,
948                                  struct sk_buff_head *rxq)
949 {
950         struct netfront_stats *rx_stats = this_cpu_ptr(queue->info->rx_stats);
951         int packets_dropped = 0;
952         struct sk_buff *skb;
953
954         while ((skb = __skb_dequeue(rxq)) != NULL) {
955                 int pull_to = NETFRONT_SKB_CB(skb)->pull_to;
956
957                 if (pull_to > skb_headlen(skb))
958                         __pskb_pull_tail(skb, pull_to - skb_headlen(skb));
959
960                 /* Ethernet work: Delayed to here as it peeks the header. */
961                 skb->protocol = eth_type_trans(skb, queue->info->netdev);
962                 skb_reset_network_header(skb);
963
964                 if (checksum_setup(queue->info->netdev, skb)) {
965                         kfree_skb(skb);
966                         packets_dropped++;
967                         queue->info->netdev->stats.rx_errors++;
968                         continue;
969                 }
970
971                 u64_stats_update_begin(&rx_stats->syncp);
972                 rx_stats->packets++;
973                 rx_stats->bytes += skb->len;
974                 u64_stats_update_end(&rx_stats->syncp);
975
976                 /* Pass it up. */
977                 napi_gro_receive(&queue->napi, skb);
978         }
979
980         return packets_dropped;
981 }
982
983 static int xennet_poll(struct napi_struct *napi, int budget)
984 {
985         struct netfront_queue *queue = container_of(napi, struct netfront_queue, napi);
986         struct net_device *dev = queue->info->netdev;
987         struct sk_buff *skb;
988         struct netfront_rx_info rinfo;
989         struct xen_netif_rx_response *rx = &rinfo.rx;
990         struct xen_netif_extra_info *extras = rinfo.extras;
991         RING_IDX i, rp;
992         int work_done;
993         struct sk_buff_head rxq;
994         struct sk_buff_head errq;
995         struct sk_buff_head tmpq;
996         int err;
997
998         spin_lock(&queue->rx_lock);
999
1000         skb_queue_head_init(&rxq);
1001         skb_queue_head_init(&errq);
1002         skb_queue_head_init(&tmpq);
1003
1004         rp = queue->rx.sring->rsp_prod;
1005         rmb(); /* Ensure we see queued responses up to 'rp'. */
1006
1007         i = queue->rx.rsp_cons;
1008         work_done = 0;
1009         while ((i != rp) && (work_done < budget)) {
1010                 memcpy(rx, RING_GET_RESPONSE(&queue->rx, i), sizeof(*rx));
1011                 memset(extras, 0, sizeof(rinfo.extras));
1012
1013                 err = xennet_get_responses(queue, &rinfo, rp, &tmpq);
1014
1015                 if (unlikely(err)) {
1016 err:
1017                         while ((skb = __skb_dequeue(&tmpq)))
1018                                 __skb_queue_tail(&errq, skb);
1019                         dev->stats.rx_errors++;
1020                         i = queue->rx.rsp_cons;
1021                         continue;
1022                 }
1023
1024                 skb = __skb_dequeue(&tmpq);
1025
1026                 if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
1027                         struct xen_netif_extra_info *gso;
1028                         gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
1029
1030                         if (unlikely(xennet_set_skb_gso(skb, gso))) {
1031                                 __skb_queue_head(&tmpq, skb);
1032                                 queue->rx.rsp_cons += skb_queue_len(&tmpq);
1033                                 goto err;
1034                         }
1035                 }
1036
1037                 NETFRONT_SKB_CB(skb)->pull_to = rx->status;
1038                 if (NETFRONT_SKB_CB(skb)->pull_to > RX_COPY_THRESHOLD)
1039                         NETFRONT_SKB_CB(skb)->pull_to = RX_COPY_THRESHOLD;
1040
1041                 skb_shinfo(skb)->frags[0].page_offset = rx->offset;
1042                 skb_frag_size_set(&skb_shinfo(skb)->frags[0], rx->status);
1043                 skb->data_len = rx->status;
1044                 skb->len += rx->status;
1045
1046                 i = xennet_fill_frags(queue, skb, &tmpq);
1047
1048                 if (rx->flags & XEN_NETRXF_csum_blank)
1049                         skb->ip_summed = CHECKSUM_PARTIAL;
1050                 else if (rx->flags & XEN_NETRXF_data_validated)
1051                         skb->ip_summed = CHECKSUM_UNNECESSARY;
1052
1053                 __skb_queue_tail(&rxq, skb);
1054
1055                 queue->rx.rsp_cons = ++i;
1056                 work_done++;
1057         }
1058
1059         __skb_queue_purge(&errq);
1060
1061         work_done -= handle_incoming_queue(queue, &rxq);
1062
1063         xennet_alloc_rx_buffers(queue);
1064
1065         if (work_done < budget) {
1066                 int more_to_do = 0;
1067
1068                 napi_complete_done(napi, work_done);
1069
1070                 RING_FINAL_CHECK_FOR_RESPONSES(&queue->rx, more_to_do);
1071                 if (more_to_do)
1072                         napi_schedule(napi);
1073         }
1074
1075         spin_unlock(&queue->rx_lock);
1076
1077         return work_done;
1078 }
1079
1080 static int xennet_change_mtu(struct net_device *dev, int mtu)
1081 {
1082         int max = xennet_can_sg(dev) ? XEN_NETIF_MAX_TX_SIZE : ETH_DATA_LEN;
1083
1084         if (mtu > max)
1085                 return -EINVAL;
1086         dev->mtu = mtu;
1087         return 0;
1088 }
1089
1090 static void xennet_get_stats64(struct net_device *dev,
1091                                struct rtnl_link_stats64 *tot)
1092 {
1093         struct netfront_info *np = netdev_priv(dev);
1094         int cpu;
1095
1096         for_each_possible_cpu(cpu) {
1097                 struct netfront_stats *rx_stats = per_cpu_ptr(np->rx_stats, cpu);
1098                 struct netfront_stats *tx_stats = per_cpu_ptr(np->tx_stats, cpu);
1099                 u64 rx_packets, rx_bytes, tx_packets, tx_bytes;
1100                 unsigned int start;
1101
1102                 do {
1103                         start = u64_stats_fetch_begin_irq(&tx_stats->syncp);
1104                         tx_packets = tx_stats->packets;
1105                         tx_bytes = tx_stats->bytes;
1106                 } while (u64_stats_fetch_retry_irq(&tx_stats->syncp, start));
1107
1108                 do {
1109                         start = u64_stats_fetch_begin_irq(&rx_stats->syncp);
1110                         rx_packets = rx_stats->packets;
1111                         rx_bytes = rx_stats->bytes;
1112                 } while (u64_stats_fetch_retry_irq(&rx_stats->syncp, start));
1113
1114                 tot->rx_packets += rx_packets;
1115                 tot->tx_packets += tx_packets;
1116                 tot->rx_bytes   += rx_bytes;
1117                 tot->tx_bytes   += tx_bytes;
1118         }
1119
1120         tot->rx_errors  = dev->stats.rx_errors;
1121         tot->tx_dropped = dev->stats.tx_dropped;
1122 }
1123
1124 static void xennet_release_tx_bufs(struct netfront_queue *queue)
1125 {
1126         struct sk_buff *skb;
1127         int i;
1128
1129         for (i = 0; i < NET_TX_RING_SIZE; i++) {
1130                 /* Skip over entries which are actually freelist references */
1131                 if (skb_entry_is_link(&queue->tx_skbs[i]))
1132                         continue;
1133
1134                 skb = queue->tx_skbs[i].skb;
1135                 get_page(queue->grant_tx_page[i]);
1136                 gnttab_end_foreign_access(queue->grant_tx_ref[i],
1137                                           GNTMAP_readonly,
1138                                           (unsigned long)page_address(queue->grant_tx_page[i]));
1139                 queue->grant_tx_page[i] = NULL;
1140                 queue->grant_tx_ref[i] = GRANT_INVALID_REF;
1141                 add_id_to_freelist(&queue->tx_skb_freelist, queue->tx_skbs, i);
1142                 dev_kfree_skb_irq(skb);
1143         }
1144 }
1145
1146 static void xennet_release_rx_bufs(struct netfront_queue *queue)
1147 {
1148         int id, ref;
1149
1150         spin_lock_bh(&queue->rx_lock);
1151
1152         for (id = 0; id < NET_RX_RING_SIZE; id++) {
1153                 struct sk_buff *skb;
1154                 struct page *page;
1155
1156                 skb = queue->rx_skbs[id];
1157                 if (!skb)
1158                         continue;
1159
1160                 ref = queue->grant_rx_ref[id];
1161                 if (ref == GRANT_INVALID_REF)
1162                         continue;
1163
1164                 page = skb_frag_page(&skb_shinfo(skb)->frags[0]);
1165
1166                 /* gnttab_end_foreign_access() needs a page ref until
1167                  * foreign access is ended (which may be deferred).
1168                  */
1169                 get_page(page);
1170                 gnttab_end_foreign_access(ref, 0,
1171                                           (unsigned long)page_address(page));
1172                 queue->grant_rx_ref[id] = GRANT_INVALID_REF;
1173
1174                 kfree_skb(skb);
1175         }
1176
1177         spin_unlock_bh(&queue->rx_lock);
1178 }
1179
1180 static netdev_features_t xennet_fix_features(struct net_device *dev,
1181         netdev_features_t features)
1182 {
1183         struct netfront_info *np = netdev_priv(dev);
1184
1185         if (features & NETIF_F_SG &&
1186             !xenbus_read_unsigned(np->xbdev->otherend, "feature-sg", 0))
1187                 features &= ~NETIF_F_SG;
1188
1189         if (features & NETIF_F_IPV6_CSUM &&
1190             !xenbus_read_unsigned(np->xbdev->otherend,
1191                                   "feature-ipv6-csum-offload", 0))
1192                 features &= ~NETIF_F_IPV6_CSUM;
1193
1194         if (features & NETIF_F_TSO &&
1195             !xenbus_read_unsigned(np->xbdev->otherend, "feature-gso-tcpv4", 0))
1196                 features &= ~NETIF_F_TSO;
1197
1198         if (features & NETIF_F_TSO6 &&
1199             !xenbus_read_unsigned(np->xbdev->otherend, "feature-gso-tcpv6", 0))
1200                 features &= ~NETIF_F_TSO6;
1201
1202         return features;
1203 }
1204
1205 static int xennet_set_features(struct net_device *dev,
1206         netdev_features_t features)
1207 {
1208         if (!(features & NETIF_F_SG) && dev->mtu > ETH_DATA_LEN) {
1209                 netdev_info(dev, "Reducing MTU because no SG offload");
1210                 dev->mtu = ETH_DATA_LEN;
1211         }
1212
1213         return 0;
1214 }
1215
1216 static irqreturn_t xennet_tx_interrupt(int irq, void *dev_id)
1217 {
1218         struct netfront_queue *queue = dev_id;
1219         unsigned long flags;
1220
1221         spin_lock_irqsave(&queue->tx_lock, flags);
1222         xennet_tx_buf_gc(queue);
1223         spin_unlock_irqrestore(&queue->tx_lock, flags);
1224
1225         return IRQ_HANDLED;
1226 }
1227
1228 static irqreturn_t xennet_rx_interrupt(int irq, void *dev_id)
1229 {
1230         struct netfront_queue *queue = dev_id;
1231         struct net_device *dev = queue->info->netdev;
1232
1233         if (likely(netif_carrier_ok(dev) &&
1234                    RING_HAS_UNCONSUMED_RESPONSES(&queue->rx)))
1235                 napi_schedule(&queue->napi);
1236
1237         return IRQ_HANDLED;
1238 }
1239
1240 static irqreturn_t xennet_interrupt(int irq, void *dev_id)
1241 {
1242         xennet_tx_interrupt(irq, dev_id);
1243         xennet_rx_interrupt(irq, dev_id);
1244         return IRQ_HANDLED;
1245 }
1246
1247 #ifdef CONFIG_NET_POLL_CONTROLLER
1248 static void xennet_poll_controller(struct net_device *dev)
1249 {
1250         /* Poll each queue */
1251         struct netfront_info *info = netdev_priv(dev);
1252         unsigned int num_queues = dev->real_num_tx_queues;
1253         unsigned int i;
1254         for (i = 0; i < num_queues; ++i)
1255                 xennet_interrupt(0, &info->queues[i]);
1256 }
1257 #endif
1258
1259 static const struct net_device_ops xennet_netdev_ops = {
1260         .ndo_open            = xennet_open,
1261         .ndo_stop            = xennet_close,
1262         .ndo_start_xmit      = xennet_start_xmit,
1263         .ndo_change_mtu      = xennet_change_mtu,
1264         .ndo_get_stats64     = xennet_get_stats64,
1265         .ndo_set_mac_address = eth_mac_addr,
1266         .ndo_validate_addr   = eth_validate_addr,
1267         .ndo_fix_features    = xennet_fix_features,
1268         .ndo_set_features    = xennet_set_features,
1269         .ndo_select_queue    = xennet_select_queue,
1270 #ifdef CONFIG_NET_POLL_CONTROLLER
1271         .ndo_poll_controller = xennet_poll_controller,
1272 #endif
1273 };
1274
1275 static void xennet_free_netdev(struct net_device *netdev)
1276 {
1277         struct netfront_info *np = netdev_priv(netdev);
1278
1279         free_percpu(np->rx_stats);
1280         free_percpu(np->tx_stats);
1281         free_netdev(netdev);
1282 }
1283
1284 static struct net_device *xennet_create_dev(struct xenbus_device *dev)
1285 {
1286         int err;
1287         struct net_device *netdev;
1288         struct netfront_info *np;
1289
1290         netdev = alloc_etherdev_mq(sizeof(struct netfront_info), xennet_max_queues);
1291         if (!netdev)
1292                 return ERR_PTR(-ENOMEM);
1293
1294         np                   = netdev_priv(netdev);
1295         np->xbdev            = dev;
1296
1297         np->queues = NULL;
1298
1299         err = -ENOMEM;
1300         np->rx_stats = netdev_alloc_pcpu_stats(struct netfront_stats);
1301         if (np->rx_stats == NULL)
1302                 goto exit;
1303         np->tx_stats = netdev_alloc_pcpu_stats(struct netfront_stats);
1304         if (np->tx_stats == NULL)
1305                 goto exit;
1306
1307         netdev->netdev_ops      = &xennet_netdev_ops;
1308
1309         netdev->features        = NETIF_F_IP_CSUM | NETIF_F_RXCSUM |
1310                                   NETIF_F_GSO_ROBUST;
1311         netdev->hw_features     = NETIF_F_SG |
1312                                   NETIF_F_IPV6_CSUM |
1313                                   NETIF_F_TSO | NETIF_F_TSO6;
1314
1315         /*
1316          * Assume that all hw features are available for now. This set
1317          * will be adjusted by the call to netdev_update_features() in
1318          * xennet_connect() which is the earliest point where we can
1319          * negotiate with the backend regarding supported features.
1320          */
1321         netdev->features |= netdev->hw_features;
1322
1323         netdev->ethtool_ops = &xennet_ethtool_ops;
1324         netdev->min_mtu = ETH_MIN_MTU;
1325         netdev->max_mtu = XEN_NETIF_MAX_TX_SIZE;
1326         SET_NETDEV_DEV(netdev, &dev->dev);
1327
1328         np->netdev = netdev;
1329
1330         netif_carrier_off(netdev);
1331
1332         xenbus_switch_state(dev, XenbusStateInitialising);
1333         return netdev;
1334
1335  exit:
1336         xennet_free_netdev(netdev);
1337         return ERR_PTR(err);
1338 }
1339
1340 /**
1341  * Entry point to this code when a new device is created.  Allocate the basic
1342  * structures and the ring buffers for communication with the backend, and
1343  * inform the backend of the appropriate details for those.
1344  */
1345 static int netfront_probe(struct xenbus_device *dev,
1346                           const struct xenbus_device_id *id)
1347 {
1348         int err;
1349         struct net_device *netdev;
1350         struct netfront_info *info;
1351
1352         netdev = xennet_create_dev(dev);
1353         if (IS_ERR(netdev)) {
1354                 err = PTR_ERR(netdev);
1355                 xenbus_dev_fatal(dev, err, "creating netdev");
1356                 return err;
1357         }
1358
1359         info = netdev_priv(netdev);
1360         dev_set_drvdata(&dev->dev, info);
1361 #ifdef CONFIG_SYSFS
1362         info->netdev->sysfs_groups[0] = &xennet_dev_group;
1363 #endif
1364
1365         return 0;
1366 }
1367
1368 static void xennet_end_access(int ref, void *page)
1369 {
1370         /* This frees the page as a side-effect */
1371         if (ref != GRANT_INVALID_REF)
1372                 gnttab_end_foreign_access(ref, 0, (unsigned long)page);
1373 }
1374
1375 static void xennet_disconnect_backend(struct netfront_info *info)
1376 {
1377         unsigned int i = 0;
1378         unsigned int num_queues = info->netdev->real_num_tx_queues;
1379
1380         netif_carrier_off(info->netdev);
1381
1382         for (i = 0; i < num_queues && info->queues; ++i) {
1383                 struct netfront_queue *queue = &info->queues[i];
1384
1385                 del_timer_sync(&queue->rx_refill_timer);
1386
1387                 if (queue->tx_irq && (queue->tx_irq == queue->rx_irq))
1388                         unbind_from_irqhandler(queue->tx_irq, queue);
1389                 if (queue->tx_irq && (queue->tx_irq != queue->rx_irq)) {
1390                         unbind_from_irqhandler(queue->tx_irq, queue);
1391                         unbind_from_irqhandler(queue->rx_irq, queue);
1392                 }
1393                 queue->tx_evtchn = queue->rx_evtchn = 0;
1394                 queue->tx_irq = queue->rx_irq = 0;
1395
1396                 if (netif_running(info->netdev))
1397                         napi_synchronize(&queue->napi);
1398
1399                 xennet_release_tx_bufs(queue);
1400                 xennet_release_rx_bufs(queue);
1401                 gnttab_free_grant_references(queue->gref_tx_head);
1402                 gnttab_free_grant_references(queue->gref_rx_head);
1403
1404                 /* End access and free the pages */
1405                 xennet_end_access(queue->tx_ring_ref, queue->tx.sring);
1406                 xennet_end_access(queue->rx_ring_ref, queue->rx.sring);
1407
1408                 queue->tx_ring_ref = GRANT_INVALID_REF;
1409                 queue->rx_ring_ref = GRANT_INVALID_REF;
1410                 queue->tx.sring = NULL;
1411                 queue->rx.sring = NULL;
1412         }
1413 }
1414
1415 /**
1416  * We are reconnecting to the backend, due to a suspend/resume, or a backend
1417  * driver restart.  We tear down our netif structure and recreate it, but
1418  * leave the device-layer structures intact so that this is transparent to the
1419  * rest of the kernel.
1420  */
1421 static int netfront_resume(struct xenbus_device *dev)
1422 {
1423         struct netfront_info *info = dev_get_drvdata(&dev->dev);
1424
1425         dev_dbg(&dev->dev, "%s\n", dev->nodename);
1426
1427         xennet_disconnect_backend(info);
1428         return 0;
1429 }
1430
1431 static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[])
1432 {
1433         char *s, *e, *macstr;
1434         int i;
1435
1436         macstr = s = xenbus_read(XBT_NIL, dev->nodename, "mac", NULL);
1437         if (IS_ERR(macstr))
1438                 return PTR_ERR(macstr);
1439
1440         for (i = 0; i < ETH_ALEN; i++) {
1441                 mac[i] = simple_strtoul(s, &e, 16);
1442                 if ((s == e) || (*e != ((i == ETH_ALEN-1) ? '\0' : ':'))) {
1443                         kfree(macstr);
1444                         return -ENOENT;
1445                 }
1446                 s = e+1;
1447         }
1448
1449         kfree(macstr);
1450         return 0;
1451 }
1452
1453 static int setup_netfront_single(struct netfront_queue *queue)
1454 {
1455         int err;
1456
1457         err = xenbus_alloc_evtchn(queue->info->xbdev, &queue->tx_evtchn);
1458         if (err < 0)
1459                 goto fail;
1460
1461         err = bind_evtchn_to_irqhandler(queue->tx_evtchn,
1462                                         xennet_interrupt,
1463                                         0, queue->info->netdev->name, queue);
1464         if (err < 0)
1465                 goto bind_fail;
1466         queue->rx_evtchn = queue->tx_evtchn;
1467         queue->rx_irq = queue->tx_irq = err;
1468
1469         return 0;
1470
1471 bind_fail:
1472         xenbus_free_evtchn(queue->info->xbdev, queue->tx_evtchn);
1473         queue->tx_evtchn = 0;
1474 fail:
1475         return err;
1476 }
1477
1478 static int setup_netfront_split(struct netfront_queue *queue)
1479 {
1480         int err;
1481
1482         err = xenbus_alloc_evtchn(queue->info->xbdev, &queue->tx_evtchn);
1483         if (err < 0)
1484                 goto fail;
1485         err = xenbus_alloc_evtchn(queue->info->xbdev, &queue->rx_evtchn);
1486         if (err < 0)
1487                 goto alloc_rx_evtchn_fail;
1488
1489         snprintf(queue->tx_irq_name, sizeof(queue->tx_irq_name),
1490                  "%s-tx", queue->name);
1491         err = bind_evtchn_to_irqhandler(queue->tx_evtchn,
1492                                         xennet_tx_interrupt,
1493                                         0, queue->tx_irq_name, queue);
1494         if (err < 0)
1495                 goto bind_tx_fail;
1496         queue->tx_irq = err;
1497
1498         snprintf(queue->rx_irq_name, sizeof(queue->rx_irq_name),
1499                  "%s-rx", queue->name);
1500         err = bind_evtchn_to_irqhandler(queue->rx_evtchn,
1501                                         xennet_rx_interrupt,
1502                                         0, queue->rx_irq_name, queue);
1503         if (err < 0)
1504                 goto bind_rx_fail;
1505         queue->rx_irq = err;
1506
1507         return 0;
1508
1509 bind_rx_fail:
1510         unbind_from_irqhandler(queue->tx_irq, queue);
1511         queue->tx_irq = 0;
1512 bind_tx_fail:
1513         xenbus_free_evtchn(queue->info->xbdev, queue->rx_evtchn);
1514         queue->rx_evtchn = 0;
1515 alloc_rx_evtchn_fail:
1516         xenbus_free_evtchn(queue->info->xbdev, queue->tx_evtchn);
1517         queue->tx_evtchn = 0;
1518 fail:
1519         return err;
1520 }
1521
1522 static int setup_netfront(struct xenbus_device *dev,
1523                         struct netfront_queue *queue, unsigned int feature_split_evtchn)
1524 {
1525         struct xen_netif_tx_sring *txs;
1526         struct xen_netif_rx_sring *rxs;
1527         grant_ref_t gref;
1528         int err;
1529
1530         queue->tx_ring_ref = GRANT_INVALID_REF;
1531         queue->rx_ring_ref = GRANT_INVALID_REF;
1532         queue->rx.sring = NULL;
1533         queue->tx.sring = NULL;
1534
1535         txs = (struct xen_netif_tx_sring *)get_zeroed_page(GFP_NOIO | __GFP_HIGH);
1536         if (!txs) {
1537                 err = -ENOMEM;
1538                 xenbus_dev_fatal(dev, err, "allocating tx ring page");
1539                 goto fail;
1540         }
1541         SHARED_RING_INIT(txs);
1542         FRONT_RING_INIT(&queue->tx, txs, XEN_PAGE_SIZE);
1543
1544         err = xenbus_grant_ring(dev, txs, 1, &gref);
1545         if (err < 0)
1546                 goto grant_tx_ring_fail;
1547         queue->tx_ring_ref = gref;
1548
1549         rxs = (struct xen_netif_rx_sring *)get_zeroed_page(GFP_NOIO | __GFP_HIGH);
1550         if (!rxs) {
1551                 err = -ENOMEM;
1552                 xenbus_dev_fatal(dev, err, "allocating rx ring page");
1553                 goto alloc_rx_ring_fail;
1554         }
1555         SHARED_RING_INIT(rxs);
1556         FRONT_RING_INIT(&queue->rx, rxs, XEN_PAGE_SIZE);
1557
1558         err = xenbus_grant_ring(dev, rxs, 1, &gref);
1559         if (err < 0)
1560                 goto grant_rx_ring_fail;
1561         queue->rx_ring_ref = gref;
1562
1563         if (feature_split_evtchn)
1564                 err = setup_netfront_split(queue);
1565         /* setup single event channel if
1566          *  a) feature-split-event-channels == 0
1567          *  b) feature-split-event-channels == 1 but failed to setup
1568          */
1569         if (!feature_split_evtchn || (feature_split_evtchn && err))
1570                 err = setup_netfront_single(queue);
1571
1572         if (err)
1573                 goto alloc_evtchn_fail;
1574
1575         return 0;
1576
1577         /* If we fail to setup netfront, it is safe to just revoke access to
1578          * granted pages because backend is not accessing it at this point.
1579          */
1580 alloc_evtchn_fail:
1581         gnttab_end_foreign_access_ref(queue->rx_ring_ref, 0);
1582 grant_rx_ring_fail:
1583         free_page((unsigned long)rxs);
1584 alloc_rx_ring_fail:
1585         gnttab_end_foreign_access_ref(queue->tx_ring_ref, 0);
1586 grant_tx_ring_fail:
1587         free_page((unsigned long)txs);
1588 fail:
1589         return err;
1590 }
1591
1592 /* Queue-specific initialisation
1593  * This used to be done in xennet_create_dev() but must now
1594  * be run per-queue.
1595  */
1596 static int xennet_init_queue(struct netfront_queue *queue)
1597 {
1598         unsigned short i;
1599         int err = 0;
1600
1601         spin_lock_init(&queue->tx_lock);
1602         spin_lock_init(&queue->rx_lock);
1603
1604         timer_setup(&queue->rx_refill_timer, rx_refill_timeout, 0);
1605
1606         snprintf(queue->name, sizeof(queue->name), "%s-q%u",
1607                  queue->info->netdev->name, queue->id);
1608
1609         /* Initialise tx_skbs as a free chain containing every entry. */
1610         queue->tx_skb_freelist = 0;
1611         for (i = 0; i < NET_TX_RING_SIZE; i++) {
1612                 skb_entry_set_link(&queue->tx_skbs[i], i+1);
1613                 queue->grant_tx_ref[i] = GRANT_INVALID_REF;
1614                 queue->grant_tx_page[i] = NULL;
1615         }
1616
1617         /* Clear out rx_skbs */
1618         for (i = 0; i < NET_RX_RING_SIZE; i++) {
1619                 queue->rx_skbs[i] = NULL;
1620                 queue->grant_rx_ref[i] = GRANT_INVALID_REF;
1621         }
1622
1623         /* A grant for every tx ring slot */
1624         if (gnttab_alloc_grant_references(NET_TX_RING_SIZE,
1625                                           &queue->gref_tx_head) < 0) {
1626                 pr_alert("can't alloc tx grant refs\n");
1627                 err = -ENOMEM;
1628                 goto exit;
1629         }
1630
1631         /* A grant for every rx ring slot */
1632         if (gnttab_alloc_grant_references(NET_RX_RING_SIZE,
1633                                           &queue->gref_rx_head) < 0) {
1634                 pr_alert("can't alloc rx grant refs\n");
1635                 err = -ENOMEM;
1636                 goto exit_free_tx;
1637         }
1638
1639         return 0;
1640
1641  exit_free_tx:
1642         gnttab_free_grant_references(queue->gref_tx_head);
1643  exit:
1644         return err;
1645 }
1646
1647 static int write_queue_xenstore_keys(struct netfront_queue *queue,
1648                            struct xenbus_transaction *xbt, int write_hierarchical)
1649 {
1650         /* Write the queue-specific keys into XenStore in the traditional
1651          * way for a single queue, or in a queue subkeys for multiple
1652          * queues.
1653          */
1654         struct xenbus_device *dev = queue->info->xbdev;
1655         int err;
1656         const char *message;
1657         char *path;
1658         size_t pathsize;
1659
1660         /* Choose the correct place to write the keys */
1661         if (write_hierarchical) {
1662                 pathsize = strlen(dev->nodename) + 10;
1663                 path = kzalloc(pathsize, GFP_KERNEL);
1664                 if (!path) {
1665                         err = -ENOMEM;
1666                         message = "out of memory while writing ring references";
1667                         goto error;
1668                 }
1669                 snprintf(path, pathsize, "%s/queue-%u",
1670                                 dev->nodename, queue->id);
1671         } else {
1672                 path = (char *)dev->nodename;
1673         }
1674
1675         /* Write ring references */
1676         err = xenbus_printf(*xbt, path, "tx-ring-ref", "%u",
1677                         queue->tx_ring_ref);
1678         if (err) {
1679                 message = "writing tx-ring-ref";
1680                 goto error;
1681         }
1682
1683         err = xenbus_printf(*xbt, path, "rx-ring-ref", "%u",
1684                         queue->rx_ring_ref);
1685         if (err) {
1686                 message = "writing rx-ring-ref";
1687                 goto error;
1688         }
1689
1690         /* Write event channels; taking into account both shared
1691          * and split event channel scenarios.
1692          */
1693         if (queue->tx_evtchn == queue->rx_evtchn) {
1694                 /* Shared event channel */
1695                 err = xenbus_printf(*xbt, path,
1696                                 "event-channel", "%u", queue->tx_evtchn);
1697                 if (err) {
1698                         message = "writing event-channel";
1699                         goto error;
1700                 }
1701         } else {
1702                 /* Split event channels */
1703                 err = xenbus_printf(*xbt, path,
1704                                 "event-channel-tx", "%u", queue->tx_evtchn);
1705                 if (err) {
1706                         message = "writing event-channel-tx";
1707                         goto error;
1708                 }
1709
1710                 err = xenbus_printf(*xbt, path,
1711                                 "event-channel-rx", "%u", queue->rx_evtchn);
1712                 if (err) {
1713                         message = "writing event-channel-rx";
1714                         goto error;
1715                 }
1716         }
1717
1718         if (write_hierarchical)
1719                 kfree(path);
1720         return 0;
1721
1722 error:
1723         if (write_hierarchical)
1724                 kfree(path);
1725         xenbus_dev_fatal(dev, err, "%s", message);
1726         return err;
1727 }
1728
1729 static void xennet_destroy_queues(struct netfront_info *info)
1730 {
1731         unsigned int i;
1732
1733         for (i = 0; i < info->netdev->real_num_tx_queues; i++) {
1734                 struct netfront_queue *queue = &info->queues[i];
1735
1736                 if (netif_running(info->netdev))
1737                         napi_disable(&queue->napi);
1738                 netif_napi_del(&queue->napi);
1739         }
1740
1741         kfree(info->queues);
1742         info->queues = NULL;
1743 }
1744
1745 static int xennet_create_queues(struct netfront_info *info,
1746                                 unsigned int *num_queues)
1747 {
1748         unsigned int i;
1749         int ret;
1750
1751         info->queues = kcalloc(*num_queues, sizeof(struct netfront_queue),
1752                                GFP_KERNEL);
1753         if (!info->queues)
1754                 return -ENOMEM;
1755
1756         for (i = 0; i < *num_queues; i++) {
1757                 struct netfront_queue *queue = &info->queues[i];
1758
1759                 queue->id = i;
1760                 queue->info = info;
1761
1762                 ret = xennet_init_queue(queue);
1763                 if (ret < 0) {
1764                         dev_warn(&info->xbdev->dev,
1765                                  "only created %d queues\n", i);
1766                         *num_queues = i;
1767                         break;
1768                 }
1769
1770                 netif_napi_add(queue->info->netdev, &queue->napi,
1771                                xennet_poll, 64);
1772                 if (netif_running(info->netdev))
1773                         napi_enable(&queue->napi);
1774         }
1775
1776         netif_set_real_num_tx_queues(info->netdev, *num_queues);
1777
1778         if (*num_queues == 0) {
1779                 dev_err(&info->xbdev->dev, "no queues\n");
1780                 return -EINVAL;
1781         }
1782         return 0;
1783 }
1784
1785 /* Common code used when first setting up, and when resuming. */
1786 static int talk_to_netback(struct xenbus_device *dev,
1787                            struct netfront_info *info)
1788 {
1789         const char *message;
1790         struct xenbus_transaction xbt;
1791         int err;
1792         unsigned int feature_split_evtchn;
1793         unsigned int i = 0;
1794         unsigned int max_queues = 0;
1795         struct netfront_queue *queue = NULL;
1796         unsigned int num_queues = 1;
1797
1798         info->netdev->irq = 0;
1799
1800         /* Check if backend supports multiple queues */
1801         max_queues = xenbus_read_unsigned(info->xbdev->otherend,
1802                                           "multi-queue-max-queues", 1);
1803         num_queues = min(max_queues, xennet_max_queues);
1804
1805         /* Check feature-split-event-channels */
1806         feature_split_evtchn = xenbus_read_unsigned(info->xbdev->otherend,
1807                                         "feature-split-event-channels", 0);
1808
1809         /* Read mac addr. */
1810         err = xen_net_read_mac(dev, info->netdev->dev_addr);
1811         if (err) {
1812                 xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename);
1813                 goto out;
1814         }
1815
1816         rtnl_lock();
1817         if (info->queues)
1818                 xennet_destroy_queues(info);
1819
1820         err = xennet_create_queues(info, &num_queues);
1821         if (err < 0) {
1822                 xenbus_dev_fatal(dev, err, "creating queues");
1823                 kfree(info->queues);
1824                 info->queues = NULL;
1825                 goto out;
1826         }
1827         rtnl_unlock();
1828
1829         /* Create shared ring, alloc event channel -- for each queue */
1830         for (i = 0; i < num_queues; ++i) {
1831                 queue = &info->queues[i];
1832                 err = setup_netfront(dev, queue, feature_split_evtchn);
1833                 if (err)
1834                         goto destroy_ring;
1835         }
1836
1837 again:
1838         err = xenbus_transaction_start(&xbt);
1839         if (err) {
1840                 xenbus_dev_fatal(dev, err, "starting transaction");
1841                 goto destroy_ring;
1842         }
1843
1844         if (xenbus_exists(XBT_NIL,
1845                           info->xbdev->otherend, "multi-queue-max-queues")) {
1846                 /* Write the number of queues */
1847                 err = xenbus_printf(xbt, dev->nodename,
1848                                     "multi-queue-num-queues", "%u", num_queues);
1849                 if (err) {
1850                         message = "writing multi-queue-num-queues";
1851                         goto abort_transaction_no_dev_fatal;
1852                 }
1853         }
1854
1855         if (num_queues == 1) {
1856                 err = write_queue_xenstore_keys(&info->queues[0], &xbt, 0); /* flat */
1857                 if (err)
1858                         goto abort_transaction_no_dev_fatal;
1859         } else {
1860                 /* Write the keys for each queue */
1861                 for (i = 0; i < num_queues; ++i) {
1862                         queue = &info->queues[i];
1863                         err = write_queue_xenstore_keys(queue, &xbt, 1); /* hierarchical */
1864                         if (err)
1865                                 goto abort_transaction_no_dev_fatal;
1866                 }
1867         }
1868
1869         /* The remaining keys are not queue-specific */
1870         err = xenbus_printf(xbt, dev->nodename, "request-rx-copy", "%u",
1871                             1);
1872         if (err) {
1873                 message = "writing request-rx-copy";
1874                 goto abort_transaction;
1875         }
1876
1877         err = xenbus_printf(xbt, dev->nodename, "feature-rx-notify", "%d", 1);
1878         if (err) {
1879                 message = "writing feature-rx-notify";
1880                 goto abort_transaction;
1881         }
1882
1883         err = xenbus_printf(xbt, dev->nodename, "feature-sg", "%d", 1);
1884         if (err) {
1885                 message = "writing feature-sg";
1886                 goto abort_transaction;
1887         }
1888
1889         err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv4", "%d", 1);
1890         if (err) {
1891                 message = "writing feature-gso-tcpv4";
1892                 goto abort_transaction;
1893         }
1894
1895         err = xenbus_write(xbt, dev->nodename, "feature-gso-tcpv6", "1");
1896         if (err) {
1897                 message = "writing feature-gso-tcpv6";
1898                 goto abort_transaction;
1899         }
1900
1901         err = xenbus_write(xbt, dev->nodename, "feature-ipv6-csum-offload",
1902                            "1");
1903         if (err) {
1904                 message = "writing feature-ipv6-csum-offload";
1905                 goto abort_transaction;
1906         }
1907
1908         err = xenbus_transaction_end(xbt, 0);
1909         if (err) {
1910                 if (err == -EAGAIN)
1911                         goto again;
1912                 xenbus_dev_fatal(dev, err, "completing transaction");
1913                 goto destroy_ring;
1914         }
1915
1916         return 0;
1917
1918  abort_transaction:
1919         xenbus_dev_fatal(dev, err, "%s", message);
1920 abort_transaction_no_dev_fatal:
1921         xenbus_transaction_end(xbt, 1);
1922  destroy_ring:
1923         xennet_disconnect_backend(info);
1924         rtnl_lock();
1925         xennet_destroy_queues(info);
1926  out:
1927         rtnl_unlock();
1928         device_unregister(&dev->dev);
1929         return err;
1930 }
1931
1932 static int xennet_connect(struct net_device *dev)
1933 {
1934         struct netfront_info *np = netdev_priv(dev);
1935         unsigned int num_queues = 0;
1936         int err;
1937         unsigned int j = 0;
1938         struct netfront_queue *queue = NULL;
1939
1940         if (!xenbus_read_unsigned(np->xbdev->otherend, "feature-rx-copy", 0)) {
1941                 dev_info(&dev->dev,
1942                          "backend does not support copying receive path\n");
1943                 return -ENODEV;
1944         }
1945
1946         err = talk_to_netback(np->xbdev, np);
1947         if (err)
1948                 return err;
1949
1950         /* talk_to_netback() sets the correct number of queues */
1951         num_queues = dev->real_num_tx_queues;
1952
1953         rtnl_lock();
1954         netdev_update_features(dev);
1955         rtnl_unlock();
1956
1957         if (dev->reg_state == NETREG_UNINITIALIZED) {
1958                 err = register_netdev(dev);
1959                 if (err) {
1960                         pr_warn("%s: register_netdev err=%d\n", __func__, err);
1961                         device_unregister(&np->xbdev->dev);
1962                         return err;
1963                 }
1964         }
1965
1966         /*
1967          * All public and private state should now be sane.  Get
1968          * ready to start sending and receiving packets and give the driver
1969          * domain a kick because we've probably just requeued some
1970          * packets.
1971          */
1972         netif_carrier_on(np->netdev);
1973         for (j = 0; j < num_queues; ++j) {
1974                 queue = &np->queues[j];
1975
1976                 notify_remote_via_irq(queue->tx_irq);
1977                 if (queue->tx_irq != queue->rx_irq)
1978                         notify_remote_via_irq(queue->rx_irq);
1979
1980                 spin_lock_irq(&queue->tx_lock);
1981                 xennet_tx_buf_gc(queue);
1982                 spin_unlock_irq(&queue->tx_lock);
1983
1984                 spin_lock_bh(&queue->rx_lock);
1985                 xennet_alloc_rx_buffers(queue);
1986                 spin_unlock_bh(&queue->rx_lock);
1987         }
1988
1989         return 0;
1990 }
1991
1992 /**
1993  * Callback received when the backend's state changes.
1994  */
1995 static void netback_changed(struct xenbus_device *dev,
1996                             enum xenbus_state backend_state)
1997 {
1998         struct netfront_info *np = dev_get_drvdata(&dev->dev);
1999         struct net_device *netdev = np->netdev;
2000
2001         dev_dbg(&dev->dev, "%s\n", xenbus_strstate(backend_state));
2002
2003         switch (backend_state) {
2004         case XenbusStateInitialising:
2005         case XenbusStateInitialised:
2006         case XenbusStateReconfiguring:
2007         case XenbusStateReconfigured:
2008         case XenbusStateUnknown:
2009                 break;
2010
2011         case XenbusStateInitWait:
2012                 if (dev->state != XenbusStateInitialising)
2013                         break;
2014                 if (xennet_connect(netdev) != 0)
2015                         break;
2016                 xenbus_switch_state(dev, XenbusStateConnected);
2017                 break;
2018
2019         case XenbusStateConnected:
2020                 netdev_notify_peers(netdev);
2021                 break;
2022
2023         case XenbusStateClosed:
2024                 wake_up_all(&module_unload_q);
2025                 if (dev->state == XenbusStateClosed)
2026                         break;
2027                 /* Missed the backend's CLOSING state -- fallthrough */
2028         case XenbusStateClosing:
2029                 wake_up_all(&module_unload_q);
2030                 xenbus_frontend_closed(dev);
2031                 break;
2032         }
2033 }
2034
2035 static const struct xennet_stat {
2036         char name[ETH_GSTRING_LEN];
2037         u16 offset;
2038 } xennet_stats[] = {
2039         {
2040                 "rx_gso_checksum_fixup",
2041                 offsetof(struct netfront_info, rx_gso_checksum_fixup)
2042         },
2043 };
2044
2045 static int xennet_get_sset_count(struct net_device *dev, int string_set)
2046 {
2047         switch (string_set) {
2048         case ETH_SS_STATS:
2049                 return ARRAY_SIZE(xennet_stats);
2050         default:
2051                 return -EINVAL;
2052         }
2053 }
2054
2055 static void xennet_get_ethtool_stats(struct net_device *dev,
2056                                      struct ethtool_stats *stats, u64 * data)
2057 {
2058         void *np = netdev_priv(dev);
2059         int i;
2060
2061         for (i = 0; i < ARRAY_SIZE(xennet_stats); i++)
2062                 data[i] = atomic_read((atomic_t *)(np + xennet_stats[i].offset));
2063 }
2064
2065 static void xennet_get_strings(struct net_device *dev, u32 stringset, u8 * data)
2066 {
2067         int i;
2068
2069         switch (stringset) {
2070         case ETH_SS_STATS:
2071                 for (i = 0; i < ARRAY_SIZE(xennet_stats); i++)
2072                         memcpy(data + i * ETH_GSTRING_LEN,
2073                                xennet_stats[i].name, ETH_GSTRING_LEN);
2074                 break;
2075         }
2076 }
2077
2078 static const struct ethtool_ops xennet_ethtool_ops =
2079 {
2080         .get_link = ethtool_op_get_link,
2081
2082         .get_sset_count = xennet_get_sset_count,
2083         .get_ethtool_stats = xennet_get_ethtool_stats,
2084         .get_strings = xennet_get_strings,
2085 };
2086
2087 #ifdef CONFIG_SYSFS
2088 static ssize_t show_rxbuf(struct device *dev,
2089                           struct device_attribute *attr, char *buf)
2090 {
2091         return sprintf(buf, "%lu\n", NET_RX_RING_SIZE);
2092 }
2093
2094 static ssize_t store_rxbuf(struct device *dev,
2095                            struct device_attribute *attr,
2096                            const char *buf, size_t len)
2097 {
2098         char *endp;
2099         unsigned long target;
2100
2101         if (!capable(CAP_NET_ADMIN))
2102                 return -EPERM;
2103
2104         target = simple_strtoul(buf, &endp, 0);
2105         if (endp == buf)
2106                 return -EBADMSG;
2107
2108         /* rxbuf_min and rxbuf_max are no longer configurable. */
2109
2110         return len;
2111 }
2112
2113 static DEVICE_ATTR(rxbuf_min, S_IRUGO|S_IWUSR, show_rxbuf, store_rxbuf);
2114 static DEVICE_ATTR(rxbuf_max, S_IRUGO|S_IWUSR, show_rxbuf, store_rxbuf);
2115 static DEVICE_ATTR(rxbuf_cur, S_IRUGO, show_rxbuf, NULL);
2116
2117 static struct attribute *xennet_dev_attrs[] = {
2118         &dev_attr_rxbuf_min.attr,
2119         &dev_attr_rxbuf_max.attr,
2120         &dev_attr_rxbuf_cur.attr,
2121         NULL
2122 };
2123
2124 static const struct attribute_group xennet_dev_group = {
2125         .attrs = xennet_dev_attrs
2126 };
2127 #endif /* CONFIG_SYSFS */
2128
2129 static int xennet_remove(struct xenbus_device *dev)
2130 {
2131         struct netfront_info *info = dev_get_drvdata(&dev->dev);
2132
2133         dev_dbg(&dev->dev, "%s\n", dev->nodename);
2134
2135         if (xenbus_read_driver_state(dev->otherend) != XenbusStateClosed) {
2136                 xenbus_switch_state(dev, XenbusStateClosing);
2137                 wait_event(module_unload_q,
2138                            xenbus_read_driver_state(dev->otherend) ==
2139                            XenbusStateClosing);
2140
2141                 xenbus_switch_state(dev, XenbusStateClosed);
2142                 wait_event(module_unload_q,
2143                            xenbus_read_driver_state(dev->otherend) ==
2144                            XenbusStateClosed ||
2145                            xenbus_read_driver_state(dev->otherend) ==
2146                            XenbusStateUnknown);
2147         }
2148
2149         xennet_disconnect_backend(info);
2150
2151         if (info->netdev->reg_state == NETREG_REGISTERED)
2152                 unregister_netdev(info->netdev);
2153
2154         if (info->queues) {
2155                 rtnl_lock();
2156                 xennet_destroy_queues(info);
2157                 rtnl_unlock();
2158         }
2159         xennet_free_netdev(info->netdev);
2160
2161         return 0;
2162 }
2163
2164 static const struct xenbus_device_id netfront_ids[] = {
2165         { "vif" },
2166         { "" }
2167 };
2168
2169 static struct xenbus_driver netfront_driver = {
2170         .ids = netfront_ids,
2171         .probe = netfront_probe,
2172         .remove = xennet_remove,
2173         .resume = netfront_resume,
2174         .otherend_changed = netback_changed,
2175 };
2176
2177 static int __init netif_init(void)
2178 {
2179         if (!xen_domain())
2180                 return -ENODEV;
2181
2182         if (!xen_has_pv_nic_devices())
2183                 return -ENODEV;
2184
2185         pr_info("Initialising Xen virtual ethernet driver\n");
2186
2187         /* Allow as many queues as there are CPUs inut max. 8 if user has not
2188          * specified a value.
2189          */
2190         if (xennet_max_queues == 0)
2191                 xennet_max_queues = min_t(unsigned int, MAX_QUEUES_DEFAULT,
2192                                           num_online_cpus());
2193
2194         return xenbus_register_frontend(&netfront_driver);
2195 }
2196 module_init(netif_init);
2197
2198
2199 static void __exit netif_exit(void)
2200 {
2201         xenbus_unregister_driver(&netfront_driver);
2202 }
2203 module_exit(netif_exit);
2204
2205 MODULE_DESCRIPTION("Xen virtual network device frontend");
2206 MODULE_LICENSE("GPL");
2207 MODULE_ALIAS("xen:vif");
2208 MODULE_ALIAS("xennet");