vhost/scsi: Use common handling code in request queue handler

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>

1 files changed, 164 insertions, 197 deletions

diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
index 4cd03a1d7f21..50dffe83714c 100644
--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -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: