Since virtio_scsi has supported multi virtqueue already,
it is natural to map virtque to hw-queue of blk-mq.
Cc: Paolo Bonzini <pbonz...@redhat.com>
Signed-off-by: Ming Lei <ming....@canonical.com>
---
drivers/scsi/virtio_scsi.c | 154 ++++----------------------------------------
1 file changed, 14 insertions(+), 140 deletions(-)
diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
index b83846f..719adb2 100644
--- a/drivers/scsi/virtio_scsi.c
+++ b/drivers/scsi/virtio_scsi.c
@@ -65,36 +65,6 @@ struct virtio_scsi_vq {
struct virtqueue *vq;
};
-/*
- * Per-target queue state.
- *
- * This struct holds the data needed by the queue steering policy. When a
- * target is sent multiple requests, we need to drive them to the same queue so
- * that FIFO processing order is kept. However, if a target was idle, we can
- * choose a queue arbitrarily. In this case the queue is chosen according to
- * the current VCPU, so the driver expects the number of request queues to be
- * equal to the number of VCPUs. This makes it easy and fast to select the
- * queue, and also lets the driver optimize the IRQ affinity for the virtqueues
- * (each virtqueue's affinity is set to the CPU that "owns" the queue).
- *
- * tgt_seq is held to serialize reading and writing req_vq.
- *
- * Decrements of reqs are never concurrent with writes of req_vq: before the
- * decrement reqs will be != 0; after the decrement the virtqueue completion
- * routine will not use the req_vq so it can be changed by a new request.
- * Thus they can happen outside the tgt_seq, provided of course we make reqs
- * an atomic_t.
- */
-struct virtio_scsi_target_state {
- seqcount_t tgt_seq;
-
- /* Count of outstanding requests. */
- atomic_t reqs;
-
- /* Currently active virtqueue for requests sent to this target. */
- struct virtio_scsi_vq *req_vq;
-};
-
/* Driver instance state */
struct virtio_scsi {
struct virtio_device *vdev;
@@ -150,8 +120,6 @@ static void virtscsi_complete_cmd(struct virtio_scsi
*vscsi, void *buf)
struct virtio_scsi_cmd *cmd = buf;
struct scsi_cmnd *sc = cmd->sc;
struct virtio_scsi_cmd_resp *resp = &cmd->resp.cmd;
- struct virtio_scsi_target_state *tgt =
- scsi_target(sc->device)->hostdata;
dev_dbg(&sc->device->sdev_gendev,
"cmd %p response %u status %#02x sense_len %u\n",
@@ -205,8 +173,6 @@ static void virtscsi_complete_cmd(struct virtio_scsi
*vscsi, void *buf)
}
sc->scsi_done(sc);
-
- atomic_dec(&tgt->reqs);
}
static void virtscsi_vq_done(struct virtio_scsi *vscsi,
@@ -514,9 +480,9 @@ static void virtio_scsi_init_hdr_pi(struct
virtio_scsi_cmd_req_pi *cmd_pi,
cmd_pi->pi_bytesin = blk_rq_sectors(rq) * bi->tuple_size;
}
-static int virtscsi_queuecommand(struct virtio_scsi *vscsi,
- struct virtio_scsi_vq *req_vq,
- struct scsi_cmnd *sc)
+static int __virtscsi_queuecommand(struct virtio_scsi *vscsi,
+ struct virtio_scsi_vq *req_vq,
+ struct scsi_cmnd *sc)
{
struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
struct virtio_scsi_cmd *cmd = scsi_cmd_priv(sc);
@@ -550,63 +516,15 @@ static int virtscsi_queuecommand(struct virtio_scsi
*vscsi,
return 0;
}
-static int virtscsi_queuecommand_single(struct Scsi_Host *sh,
- struct scsi_cmnd *sc)
-{
- struct virtio_scsi *vscsi = shost_priv(sh);
- struct virtio_scsi_target_state *tgt =
- scsi_target(sc->device)->hostdata;
-
- atomic_inc(&tgt->reqs);
- return virtscsi_queuecommand(vscsi, &vscsi->req_vqs[0], sc);
-}
-
-static struct virtio_scsi_vq *virtscsi_pick_vq(struct virtio_scsi *vscsi,
- struct virtio_scsi_target_state
*tgt)
-{
- struct virtio_scsi_vq *vq;
- unsigned long flags;
- u32 queue_num;
-
- local_irq_save(flags);
- if (atomic_inc_return(&tgt->reqs) > 1) {
- unsigned long seq;
-
- do {
- seq = read_seqcount_begin(&tgt->tgt_seq);
- vq = tgt->req_vq;
- } while (read_seqcount_retry(&tgt->tgt_seq, seq));
- } else {
- /* no writes can be concurrent because of atomic_t */
- write_seqcount_begin(&tgt->tgt_seq);
-
- /* keep previous req_vq if a reader just arrived */
- if (unlikely(atomic_read(&tgt->reqs) > 1)) {
- vq = tgt->req_vq;
- goto unlock;
- }
-
- queue_num = smp_processor_id();
- while (unlikely(queue_num >= vscsi->num_queues))
- queue_num -= vscsi->num_queues;
- tgt->req_vq = vq = &vscsi->req_vqs[queue_num];
- unlock:
- write_seqcount_end(&tgt->tgt_seq);
- }
- local_irq_restore(flags);
-
- return vq;
-}
-
-static int virtscsi_queuecommand_multi(struct Scsi_Host *sh,
- struct scsi_cmnd *sc)
+static int virtscsi_queuecommand(struct Scsi_Host *sh,
+ struct scsi_cmnd *sc)
{
struct virtio_scsi *vscsi = shost_priv(sh);
- struct virtio_scsi_target_state *tgt =
- scsi_target(sc->device)->hostdata;
- struct virtio_scsi_vq *req_vq = virtscsi_pick_vq(vscsi, tgt);
+ u32 tag = blk_mq_unique_tag(sc->request);
+ u16 hwq = blk_mq_unique_tag_to_hwq(tag);
+ struct virtio_scsi_vq *req_vq = &vscsi->req_vqs[hwq];
- return virtscsi_queuecommand(vscsi, req_vq, sc);
+ return __virtscsi_queuecommand(vscsi, req_vq, sc);
}
static int virtscsi_tmf(struct virtio_scsi *vscsi, struct virtio_scsi_cmd *cmd)
@@ -718,37 +636,13 @@ static int virtscsi_abort(struct scsi_cmnd *sc)
return virtscsi_tmf(vscsi, cmd);
}
-static int virtscsi_target_alloc(struct scsi_target *starget)
-{
- struct Scsi_Host *sh = dev_to_shost(starget->dev.parent);
- struct virtio_scsi *vscsi = shost_priv(sh);
-
- struct virtio_scsi_target_state *tgt =
- kmalloc(sizeof(*tgt), GFP_KERNEL);
- if (!tgt)
- return -ENOMEM;
-
- seqcount_init(&tgt->tgt_seq);
- atomic_set(&tgt->reqs, 0);
- tgt->req_vq = &vscsi->req_vqs[0];
-
- starget->hostdata = tgt;
- return 0;
-}
-
-static void virtscsi_target_destroy(struct scsi_target *starget)
-{
- struct virtio_scsi_target_state *tgt = starget->hostdata;
- kfree(tgt);
-}
-
-static struct scsi_host_template virtscsi_host_template_single = {
+static struct scsi_host_template virtscsi_host_template = {
.module = THIS_MODULE,
.name = "Virtio SCSI HBA",
.proc_name = "virtio_scsi",
.this_id = -1,
.cmd_size = sizeof(struct virtio_scsi_cmd),
- .queuecommand = virtscsi_queuecommand_single,
+ .queuecommand = virtscsi_queuecommand,
.change_queue_depth = virtscsi_change_queue_depth,
.eh_abort_handler = virtscsi_abort,
.eh_device_reset_handler = virtscsi_device_reset,
@@ -756,26 +650,8 @@ static struct scsi_host_template
virtscsi_host_template_single = {
.can_queue = 1024,
.dma_boundary = UINT_MAX,
.use_clustering = ENABLE_CLUSTERING,
- .target_alloc = virtscsi_target_alloc,
- .target_destroy = virtscsi_target_destroy,
-};
-static struct scsi_host_template virtscsi_host_template_multi = {
- .module = THIS_MODULE,
- .name = "Virtio SCSI HBA",
- .proc_name = "virtio_scsi",
- .this_id = -1,
- .cmd_size = sizeof(struct virtio_scsi_cmd),
- .queuecommand = virtscsi_queuecommand_multi,
- .change_queue_depth = virtscsi_change_queue_depth,
- .eh_abort_handler = virtscsi_abort,
- .eh_device_reset_handler = virtscsi_device_reset,
-
- .can_queue = 1024,
- .dma_boundary = UINT_MAX,
- .use_clustering = ENABLE_CLUSTERING,
- .target_alloc = virtscsi_target_alloc,
- .target_destroy = virtscsi_target_destroy,
+ .force_blk_mq = true,
};
#define virtscsi_config_get(vdev, fld) \
@@ -944,10 +820,7 @@ static int virtscsi_probe(struct virtio_device *vdev)
num_targets = virtscsi_config_get(vdev, max_target) + 1;
- if (num_queues == 1)
- hostt = &virtscsi_host_template_single;
- else
- hostt = &virtscsi_host_template_multi;
+ hostt = &virtscsi_host_template;
shost = scsi_host_alloc(hostt,
sizeof(*vscsi) + sizeof(vscsi->req_vqs[0]) * num_queues);
@@ -983,6 +856,7 @@ static int virtscsi_probe(struct virtio_device *vdev)
shost->max_id = num_targets;
shost->max_channel = 0;
shost->max_cmd_len = VIRTIO_SCSI_CDB_SIZE;
+ shost->nr_hw_queues = num_queues;
if (virtio_has_feature(vdev, VIRTIO_SCSI_F_T10_PI)) {
host_prot = SHOST_DIF_TYPE1_PROTECTION |
SHOST_DIF_TYPE2_PROTECTION |
--
1.7.9.5
--
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