From 9e5470fe2d61bd87c27c7722099bafab277f81ec Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Thu, 30 May 2019 13:28:11 +0200 Subject: [PATCH] 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 Signed-off-by: Paolo Bonzini Reviewed-by: Hannes Reinecke Reviewed-by: Ming Lei Signed-off-by: Martin K. Petersen --- drivers/scsi/virtio_scsi.c | 55 +++++++++++++++++++++++++++++++++------------- 1 file 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 = ∁ - 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, -- 2.11.0