vhost/scsi: Use common handling code in request queue handler
authorBijan Mottahedeh <bijan.mottahedeh@oracle.com>
Tue, 18 Sep 2018 00:09:49 +0000 (17:09 -0700)
committerMichael S. Tsirkin <mst@redhat.com>
Thu, 25 Oct 2018 01:16:13 +0000 (21:16 -0400)
Change the request queue handler to use common handling routines same
as the control queue handler.

Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
drivers/vhost/scsi.c

index 4cd03a1..50dffe8 100644 (file)
@@ -813,24 +813,120 @@ vhost_scsi_send_bad_target(struct vhost_scsi *vs,
                pr_err("Faulted on virtio_scsi_cmd_resp\n");
 }
 
+static int
+vhost_scsi_get_desc(struct vhost_scsi *vs, struct vhost_virtqueue *vq,
+                   struct vhost_scsi_ctx *vc)
+{
+       int ret = -ENXIO;
+
+       vc->head = vhost_get_vq_desc(vq, vq->iov,
+                                    ARRAY_SIZE(vq->iov), &vc->out, &vc->in,
+                                    NULL, NULL);
+
+       pr_debug("vhost_get_vq_desc: head: %d, out: %u in: %u\n",
+                vc->head, vc->out, vc->in);
+
+       /* On error, stop handling until the next kick. */
+       if (unlikely(vc->head < 0))
+               goto done;
+
+       /* Nothing new?  Wait for eventfd to tell us they refilled. */
+       if (vc->head == vq->num) {
+               if (unlikely(vhost_enable_notify(&vs->dev, vq))) {
+                       vhost_disable_notify(&vs->dev, vq);
+                       ret = -EAGAIN;
+               }
+               goto done;
+       }
+
+       /*
+        * Get the size of request and response buffers.
+        * FIXME: Not correct for BIDI operation
+        */
+       vc->out_size = iov_length(vq->iov, vc->out);
+       vc->in_size = iov_length(&vq->iov[vc->out], vc->in);
+
+       /*
+        * Copy over the virtio-scsi request header, which for a
+        * ANY_LAYOUT enabled guest may span multiple iovecs, or a
+        * single iovec may contain both the header + outgoing
+        * WRITE payloads.
+        *
+        * copy_from_iter() will advance out_iter, so that it will
+        * point at the start of the outgoing WRITE payload, if
+        * DMA_TO_DEVICE is set.
+        */
+       iov_iter_init(&vc->out_iter, WRITE, vq->iov, vc->out, vc->out_size);
+       ret = 0;
+
+done:
+       return ret;
+}
+
+static int
+vhost_scsi_chk_size(struct vhost_virtqueue *vq, struct vhost_scsi_ctx *vc)
+{
+       if (unlikely(vc->in_size < vc->rsp_size)) {
+               vq_err(vq,
+                      "Response buf too small, need min %zu bytes got %zu",
+                      vc->rsp_size, vc->in_size);
+               return -EINVAL;
+       } else if (unlikely(vc->out_size < vc->req_size)) {
+               vq_err(vq,
+                      "Request buf too small, need min %zu bytes got %zu",
+                      vc->req_size, vc->out_size);
+               return -EIO;
+       }
+
+       return 0;
+}
+
+static int
+vhost_scsi_get_req(struct vhost_virtqueue *vq, struct vhost_scsi_ctx *vc,
+                  struct vhost_scsi_tpg **tpgp)
+{
+       int ret = -EIO;
+
+       if (unlikely(!copy_from_iter_full(vc->req, vc->req_size,
+                                         &vc->out_iter))) {
+               vq_err(vq, "Faulted on copy_from_iter\n");
+       } else if (unlikely(*vc->lunp != 1)) {
+               /* virtio-scsi spec requires byte 0 of the lun to be 1 */
+               vq_err(vq, "Illegal virtio-scsi lun: %u\n", *vc->lunp);
+       } else {
+               struct vhost_scsi_tpg **vs_tpg, *tpg;
+
+               vs_tpg = vq->private_data;      /* validated at handler entry */
+
+               tpg = READ_ONCE(vs_tpg[*vc->target]);
+               if (unlikely(!tpg)) {
+                       vq_err(vq, "Target 0x%x does not exist\n", *vc->target);
+               } else {
+                       if (tpgp)
+                               *tpgp = tpg;
+                       ret = 0;
+               }
+       }
+
+       return ret;
+}
+
 static void
 vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
 {
        struct vhost_scsi_tpg **vs_tpg, *tpg;
        struct virtio_scsi_cmd_req v_req;
        struct virtio_scsi_cmd_req_pi v_req_pi;
+       struct vhost_scsi_ctx vc;
        struct vhost_scsi_cmd *cmd;
-       struct iov_iter out_iter, in_iter, prot_iter, data_iter;
+       struct iov_iter in_iter, prot_iter, data_iter;
        u64 tag;
        u32 exp_data_len, data_direction;
-       unsigned int out = 0, in = 0;
-       int head, ret, prot_bytes;
-       size_t req_size, rsp_size = sizeof(struct virtio_scsi_cmd_resp);
-       size_t out_size, in_size;
+       int ret, prot_bytes;
        u16 lun;
-       u8 *target, *lunp, task_attr;
+       u8 task_attr;
        bool t10_pi = vhost_has_feature(vq, VIRTIO_SCSI_F_T10_PI);
-       void *req, *cdb;
+       void *cdb;
 
        mutex_lock(&vq->mutex);
        /*
@@ -841,85 +937,47 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
        if (!vs_tpg)
                goto out;
 
+       memset(&vc, 0, sizeof(vc));
+       vc.rsp_size = sizeof(struct virtio_scsi_cmd_resp);
+
        vhost_disable_notify(&vs->dev, vq);
 
        for (;;) {
-               head = vhost_get_vq_desc(vq, vq->iov,
-                                        ARRAY_SIZE(vq->iov), &out, &in,
-                                        NULL, NULL);
-               pr_debug("vhost_get_vq_desc: head: %d, out: %u in: %u\n",
-                        head, out, in);
-               /* On error, stop handling until the next kick. */
-               if (unlikely(head < 0))
-                       break;
-               /* Nothing new?  Wait for eventfd to tell us they refilled. */
-               if (head == vq->num) {
-                       if (unlikely(vhost_enable_notify(&vs->dev, vq))) {
-                               vhost_disable_notify(&vs->dev, vq);
-                               continue;
-                       }
-                       break;
-               }
-               /*
-                * Check for a sane response buffer so we can report early
-                * errors back to the guest.
-                */
-               if (unlikely(vq->iov[out].iov_len < rsp_size)) {
-                       vq_err(vq, "Expecting at least virtio_scsi_cmd_resp"
-                               " size, got %zu bytes\n", vq->iov[out].iov_len);
-                       break;
-               }
+               ret = vhost_scsi_get_desc(vs, vq, &vc);
+               if (ret)
+                       goto err;
+
                /*
                 * Setup pointers and values based upon different virtio-scsi
                 * request header if T10_PI is enabled in KVM guest.
                 */
                if (t10_pi) {
-                       req = &v_req_pi;
-                       req_size = sizeof(v_req_pi);
-                       lunp = &v_req_pi.lun[0];
-                       target = &v_req_pi.lun[1];
+                       vc.req = &v_req_pi;
+                       vc.req_size = sizeof(v_req_pi);
+                       vc.lunp = &v_req_pi.lun[0];
+                       vc.target = &v_req_pi.lun[1];
                } else {
-                       req = &v_req;
-                       req_size = sizeof(v_req);
-                       lunp = &v_req.lun[0];
-                       target = &v_req.lun[1];
+                       vc.req = &v_req;
+                       vc.req_size = sizeof(v_req);
+                       vc.lunp = &v_req.lun[0];
+                       vc.target = &v_req.lun[1];
                }
-               /*
-                * FIXME: Not correct for BIDI operation
-                */
-               out_size = iov_length(vq->iov, out);
-               in_size = iov_length(&vq->iov[out], in);
 
                /*
-                * Copy over the virtio-scsi request header, which for a
-                * ANY_LAYOUT enabled guest may span multiple iovecs, or a
-                * single iovec may contain both the header + outgoing
-                * WRITE payloads.
-                *
-                * copy_from_iter() will advance out_iter, so that it will
-                * point at the start of the outgoing WRITE payload, if
-                * DMA_TO_DEVICE is set.
+                * Validate the size of request and response buffers.
+                * Check for a sane response buffer so we can report
+                * early errors back to the guest.
                 */
-               iov_iter_init(&out_iter, WRITE, vq->iov, out, out_size);
+               ret = vhost_scsi_chk_size(vq, &vc);
+               if (ret)
+                       goto err;
 
-               if (unlikely(!copy_from_iter_full(req, req_size, &out_iter))) {
-                       vq_err(vq, "Faulted on copy_from_iter\n");
-                       vhost_scsi_send_bad_target(vs, vq, head, out);
-                       continue;
-               }
-               /* virtio-scsi spec requires byte 0 of the lun to be 1 */
-               if (unlikely(*lunp != 1)) {
-                       vq_err(vq, "Illegal virtio-scsi lun: %u\n", *lunp);
-                       vhost_scsi_send_bad_target(vs, vq, head, out);
-                       continue;
-               }
+               ret = vhost_scsi_get_req(vq, &vc, &tpg);
+               if (ret)
+                       goto err;
+
+               ret = -EIO;     /* bad target on any error from here on */
 
-               tpg = READ_ONCE(vs_tpg[*target]);
-               if (unlikely(!tpg)) {
-                       /* Target does not exist, fail the request */
-                       vhost_scsi_send_bad_target(vs, vq, head, out);
-                       continue;
-               }
                /*
                 * Determine data_direction by calculating the total outgoing
                 * iovec sizes + incoming iovec sizes vs. virtio-scsi request +
@@ -937,17 +995,17 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
                 */
                prot_bytes = 0;
 
-               if (out_size > req_size) {
+               if (vc.out_size > vc.req_size) {
                        data_direction = DMA_TO_DEVICE;
-                       exp_data_len = out_size - req_size;
-                       data_iter = out_iter;
-               } else if (in_size > rsp_size) {
+                       exp_data_len = vc.out_size - vc.req_size;
+                       data_iter = vc.out_iter;
+               } else if (vc.in_size > vc.rsp_size) {
                        data_direction = DMA_FROM_DEVICE;
-                       exp_data_len = in_size - rsp_size;
+                       exp_data_len = vc.in_size - vc.rsp_size;
 
-                       iov_iter_init(&in_iter, READ, &vq->iov[out], in,
-                                     rsp_size + exp_data_len);
-                       iov_iter_advance(&in_iter, rsp_size);
+                       iov_iter_init(&in_iter, READ, &vq->iov[vc.out], vc.in,
+                                     vc.rsp_size + exp_data_len);
+                       iov_iter_advance(&in_iter, vc.rsp_size);
                        data_iter = in_iter;
                } else {
                        data_direction = DMA_NONE;
@@ -963,16 +1021,14 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
                                if (data_direction != DMA_TO_DEVICE) {
                                        vq_err(vq, "Received non zero pi_bytesout,"
                                                " but wrong data_direction\n");
-                                       vhost_scsi_send_bad_target(vs, vq, head, out);
-                                       continue;
+                                       goto err;
                                }
                                prot_bytes = vhost32_to_cpu(vq, v_req_pi.pi_bytesout);
                        } else if (v_req_pi.pi_bytesin) {
                                if (data_direction != DMA_FROM_DEVICE) {
                                        vq_err(vq, "Received non zero pi_bytesin,"
                                                " but wrong data_direction\n");
-                                       vhost_scsi_send_bad_target(vs, vq, head, out);
-                                       continue;
+                                       goto err;
                                }
                                prot_bytes = vhost32_to_cpu(vq, v_req_pi.pi_bytesin);
                        }
@@ -1011,8 +1067,7 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
                        vq_err(vq, "Received SCSI CDB with command_size: %d that"
                                " exceeds SCSI_MAX_VARLEN_CDB_SIZE: %d\n",
                                scsi_command_size(cdb), VHOST_SCSI_MAX_CDB_SIZE);
-                       vhost_scsi_send_bad_target(vs, vq, head, out);
-                       continue;
+                               goto err;
                }
                cmd = vhost_scsi_get_tag(vq, tpg, cdb, tag, lun, task_attr,
                                         exp_data_len + prot_bytes,
@@ -1020,13 +1075,12 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
                if (IS_ERR(cmd)) {
                        vq_err(vq, "vhost_scsi_get_tag failed %ld\n",
                               PTR_ERR(cmd));
-                       vhost_scsi_send_bad_target(vs, vq, head, out);
-                       continue;
+                       goto err;
                }
                cmd->tvc_vhost = vs;
                cmd->tvc_vq = vq;
-               cmd->tvc_resp_iov = vq->iov[out];
-               cmd->tvc_in_iovs = in;
+               cmd->tvc_resp_iov = vq->iov[vc.out];
+               cmd->tvc_in_iovs = vc.in;
 
                pr_debug("vhost_scsi got command opcode: %#02x, lun: %d\n",
                         cmd->tvc_cdb[0], cmd->tvc_lun);
@@ -1034,14 +1088,12 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
                         " %d\n", cmd, exp_data_len, prot_bytes, data_direction);
 
                if (data_direction != DMA_NONE) {
-                       ret = vhost_scsi_mapal(cmd,
-                                              prot_bytes, &prot_iter,
-                                              exp_data_len, &data_iter);
-                       if (unlikely(ret)) {
+                       if (unlikely(vhost_scsi_mapal(cmd, prot_bytes,
+                                                     &prot_iter, exp_data_len,
+                                                     &data_iter))) {
                                vq_err(vq, "Failed to map iov to sgl\n");
                                vhost_scsi_release_cmd(&cmd->tvc_se_cmd);
-                               vhost_scsi_send_bad_target(vs, vq, head, out);
-                               continue;
+                               goto err;
                        }
                }
                /*
@@ -1049,7 +1101,7 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
                 * complete the virtio-scsi request in TCM callback context via
                 * vhost_scsi_queue_data_in() and vhost_scsi_queue_status()
                 */
-               cmd->tvc_vq_desc = head;
+               cmd->tvc_vq_desc = vc.head;
                /*
                 * Dispatch cmd descriptor for cmwq execution in process
                 * context provided by vhost_scsi_workqueue.  This also ensures
@@ -1058,112 +1110,27 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
                 */
                INIT_WORK(&cmd->work, vhost_scsi_submission_work);
                queue_work(vhost_scsi_workqueue, &cmd->work);
+               ret = 0;
+err:
+               /*
+                * ENXIO:  No more requests, or read error, wait for next kick
+                * EINVAL: Invalid response buffer, drop the request
+                * EIO:    Respond with bad target
+                * EAGAIN: Pending request
+                */
+               if (ret == -ENXIO)
+                       break;
+               else if (ret == -EIO)
+                       vhost_scsi_send_bad_target(vs, vq, vc.head, vc.out);
        }
 out:
        mutex_unlock(&vq->mutex);
 }
 
-static int
-vhost_scsi_get_desc(struct vhost_scsi *vs, struct vhost_virtqueue *vq,
-                   struct vhost_scsi_ctx *vc)
-{
-       int ret = -ENXIO;
-
-       vc->head = vhost_get_vq_desc(vq, vq->iov,
-                                    ARRAY_SIZE(vq->iov), &vc->out, &vc->in,
-                                    NULL, NULL);
-
-       pr_debug("vhost_get_vq_desc: head: %d, out: %u in: %u\n",
-                vc->head, vc->out, vc->in);
-
-       /* On error, stop handling until the next kick. */
-       if (unlikely(vc->head < 0))
-               goto done;
-
-       /* Nothing new?  Wait for eventfd to tell us they refilled. */
-       if (vc->head == vq->num) {
-               if (unlikely(vhost_enable_notify(&vs->dev, vq))) {
-                       vhost_disable_notify(&vs->dev, vq);
-                       ret = -EAGAIN;
-               }
-               goto done;
-       }
-
-       /*
-        * Get the size of request and response buffers.
-        */
-       vc->out_size = iov_length(vq->iov, vc->out);
-       vc->in_size = iov_length(&vq->iov[vc->out], vc->in);
-
-       /*
-        * Copy over the virtio-scsi request header, which for a
-        * ANY_LAYOUT enabled guest may span multiple iovecs, or a
-        * single iovec may contain both the header + outgoing
-        * WRITE payloads.
-        *
-        * copy_from_iter() will advance out_iter, so that it will
-        * point at the start of the outgoing WRITE payload, if
-        * DMA_TO_DEVICE is set.
-        */
-       iov_iter_init(&vc->out_iter, WRITE, vq->iov, vc->out, vc->out_size);
-       ret = 0;
-
-done:
-       return ret;
-}
-
-static int
-vhost_scsi_chk_size(struct vhost_virtqueue *vq, struct vhost_scsi_ctx *vc)
-{
-       if (unlikely(vc->in_size < vc->rsp_size)) {
-               vq_err(vq,
-                      "Response buf too small, need min %zu bytes got %zu",
-                      vc->rsp_size, vc->in_size);
-               return -EINVAL;
-       } else if (unlikely(vc->out_size < vc->req_size)) {
-               vq_err(vq,
-                      "Request buf too small, need min %zu bytes got %zu",
-                      vc->req_size, vc->out_size);
-               return -EIO;
-       }
-
-       return 0;
-}
-
-static int
-vhost_scsi_get_req(struct vhost_virtqueue *vq, struct vhost_scsi_ctx *vc,
-                  struct vhost_scsi_tpg **tpgp)
-{
-       int ret = -EIO;
-
-       if (unlikely(!copy_from_iter_full(vc->req, vc->req_size,
-                                         &vc->out_iter)))
-               vq_err(vq, "Faulted on copy_from_iter\n");
-       else if (unlikely(*vc->lunp != 1))
-               /* virtio-scsi spec requires byte 0 of the lun to be 1 */
-               vq_err(vq, "Illegal virtio-scsi lun: %u\n", *vc->lunp);
-       else {
-               struct vhost_scsi_tpg **vs_tpg, *tpg;
-
-               vs_tpg = vq->private_data;      /* validated at handler entry */
-
-               tpg = READ_ONCE(vs_tpg[*vc->target]);
-               if (unlikely(!tpg))
-                       vq_err(vq, "Target 0x%x does not exist\n", *vc->target);
-               else {
-                       if (tpgp)
-                               *tpgp = tpg;
-                       ret = 0;
-               }
-       }
-
-       return ret;
-}
-
 static void
-vhost_scsi_send_tmf_resp(struct vhost_scsi *vs,
-                        struct vhost_virtqueue *vq,
-                        struct vhost_scsi_ctx *vc)
+vhost_scsi_send_tmf_reject(struct vhost_scsi *vs,
+                          struct vhost_virtqueue *vq,
+                          struct vhost_scsi_ctx *vc)
 {
        struct virtio_scsi_ctrl_tmf_resp __user *resp;
        struct virtio_scsi_ctrl_tmf_resp rsp;
@@ -1289,7 +1256,7 @@ vhost_scsi_ctl_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
                        goto err;
 
                if (v_req.type == VIRTIO_SCSI_T_TMF)
-                       vhost_scsi_send_tmf_resp(vs, vq, &vc);
+                       vhost_scsi_send_tmf_reject(vs, vq, &vc);
                else
                        vhost_scsi_send_an_resp(vs, vq, &vc);
 err: