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authorPaolo Bonzini <pbonzini@redhat.com>2019-05-30 14:28:11 +0300
committerMartin K. Petersen <martin.petersen@oracle.com>2019-07-22 23:44:07 +0300
commit9e5470fe2d61bd87c27c7722099bafab277f81ec (patch)
tree9cbca4e9d938b301a778d2bf5349ac68d10a5fc4 /drivers/scsi/virtio_scsi.c
parent8930a6c207918d5a5675eedab06a71096b1a3d47 (diff)
downloadlinux-9e5470fe2d61bd87c27c7722099bafab277f81ec.tar.xz
scsi: virtio_scsi: implement request batching
Adding the command and kicking the virtqueue so far was done one after another. Make the kick optional, so that we can take into account SCMD_LAST. We also need a commit_rqs callback to kick the device if blk-mq aborts the submission before the last request is reached. Suggested-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers/scsi/virtio_scsi.c')
-rw-r--r--drivers/scsi/virtio_scsi.c55
1 files changed, 40 insertions, 15 deletions
diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
index 297e1076e571..cff083049d5c 100644
--- a/drivers/scsi/virtio_scsi.c
+++ b/drivers/scsi/virtio_scsi.c
@@ -369,14 +369,7 @@ static void virtscsi_event_done(struct virtqueue *vq)
virtscsi_vq_done(vscsi, &vscsi->event_vq, virtscsi_complete_event);
};
-/**
- * virtscsi_add_cmd - add a virtio_scsi_cmd to a virtqueue
- * @vq : the struct virtqueue we're talking about
- * @cmd : command structure
- * @req_size : size of the request buffer
- * @resp_size : size of the response buffer
- */
-static int virtscsi_add_cmd(struct virtqueue *vq,
+static int __virtscsi_add_cmd(struct virtqueue *vq,
struct virtio_scsi_cmd *cmd,
size_t req_size, size_t resp_size)
{
@@ -421,17 +414,39 @@ static int virtscsi_add_cmd(struct virtqueue *vq,
return virtqueue_add_sgs(vq, sgs, out_num, in_num, cmd, GFP_ATOMIC);
}
-static int virtscsi_kick_cmd(struct virtio_scsi_vq *vq,
+static void virtscsi_kick_vq(struct virtio_scsi_vq *vq)
+{
+ bool needs_kick;
+ unsigned long flags;
+
+ spin_lock_irqsave(&vq->vq_lock, flags);
+ needs_kick = virtqueue_kick_prepare(vq->vq);
+ spin_unlock_irqrestore(&vq->vq_lock, flags);
+
+ if (needs_kick)
+ virtqueue_notify(vq->vq);
+}
+
+/**
+ * virtscsi_add_cmd - add a virtio_scsi_cmd to a virtqueue, optionally kick it
+ * @vq : the struct virtqueue we're talking about
+ * @cmd : command structure
+ * @req_size : size of the request buffer
+ * @resp_size : size of the response buffer
+ * @kick : whether to kick the virtqueue immediately
+ */
+static int virtscsi_add_cmd(struct virtio_scsi_vq *vq,
struct virtio_scsi_cmd *cmd,
- size_t req_size, size_t resp_size)
+ size_t req_size, size_t resp_size,
+ bool kick)
{
unsigned long flags;
int err;
bool needs_kick = false;
spin_lock_irqsave(&vq->vq_lock, flags);
- err = virtscsi_add_cmd(vq->vq, cmd, req_size, resp_size);
- if (!err)
+ err = __virtscsi_add_cmd(vq->vq, cmd, req_size, resp_size);
+ if (!err && kick)
needs_kick = virtqueue_kick_prepare(vq->vq);
spin_unlock_irqrestore(&vq->vq_lock, flags);
@@ -496,6 +511,7 @@ static int virtscsi_queuecommand(struct Scsi_Host *shost,
struct virtio_scsi *vscsi = shost_priv(shost);
struct virtio_scsi_vq *req_vq = virtscsi_pick_vq_mq(vscsi, sc);
struct virtio_scsi_cmd *cmd = scsi_cmd_priv(sc);
+ bool kick;
unsigned long flags;
int req_size;
int ret;
@@ -525,7 +541,8 @@ static int virtscsi_queuecommand(struct Scsi_Host *shost,
req_size = sizeof(cmd->req.cmd);
}
- ret = virtscsi_kick_cmd(req_vq, cmd, req_size, sizeof(cmd->resp.cmd));
+ kick = (sc->flags & SCMD_LAST) != 0;
+ ret = virtscsi_add_cmd(req_vq, cmd, req_size, sizeof(cmd->resp.cmd), kick);
if (ret == -EIO) {
cmd->resp.cmd.response = VIRTIO_SCSI_S_BAD_TARGET;
spin_lock_irqsave(&req_vq->vq_lock, flags);
@@ -543,8 +560,8 @@ static int virtscsi_tmf(struct virtio_scsi *vscsi, struct virtio_scsi_cmd *cmd)
int ret = FAILED;
cmd->comp = &comp;
- if (virtscsi_kick_cmd(&vscsi->ctrl_vq, cmd,
- sizeof cmd->req.tmf, sizeof cmd->resp.tmf) < 0)
+ if (virtscsi_add_cmd(&vscsi->ctrl_vq, cmd,
+ sizeof cmd->req.tmf, sizeof cmd->resp.tmf, true) < 0)
goto out;
wait_for_completion(&comp);
@@ -658,6 +675,13 @@ static int virtscsi_map_queues(struct Scsi_Host *shost)
return blk_mq_virtio_map_queues(qmap, vscsi->vdev, 2);
}
+static void virtscsi_commit_rqs(struct Scsi_Host *shost, u16 hwq)
+{
+ struct virtio_scsi *vscsi = shost_priv(shost);
+
+ virtscsi_kick_vq(&vscsi->req_vqs[hwq]);
+}
+
/*
* The host guarantees to respond to each command, although I/O
* latencies might be higher than on bare metal. Reset the timer
@@ -675,6 +699,7 @@ static struct scsi_host_template virtscsi_host_template = {
.this_id = -1,
.cmd_size = sizeof(struct virtio_scsi_cmd),
.queuecommand = virtscsi_queuecommand,
+ .commit_rqs = virtscsi_commit_rqs,
.change_queue_depth = virtscsi_change_queue_depth,
.eh_abort_handler = virtscsi_abort,
.eh_device_reset_handler = virtscsi_device_reset,