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Message-Id: <1339599394-13880-5-git-send-email-pbonzini@redhat.com>
Date: Wed, 13 Jun 2012 16:56:34 +0200
From: Paolo Bonzini <pbonzini@...hat.com>
To: linux-kernel@...r.kernel.org
Cc: linux-scsi@...r.kernel.org, kvm@...r.kernel.org
Subject: [PATCH 4/4] virtio-scsi: split scatterlist per target
To improve performance for I/O to different targets, add a separate
scatterlist for each of them.
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
---
drivers/scsi/virtio_scsi.c | 141 +++++++++++++++++++++++++++++---------------
1 files changed, 94 insertions(+), 47 deletions(-)
diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
index facfc90..1152a77 100644
--- a/drivers/scsi/virtio_scsi.c
+++ b/drivers/scsi/virtio_scsi.c
@@ -50,18 +50,24 @@ struct virtio_scsi_vq {
struct virtqueue *vq;
};
+/* Per-target queue state */
+struct virtio_scsi_target_state {
+ /* Protects sg. Lock hierarchy is tgt_lock -> vq_lock. */
+ spinlock_t tgt_lock;
+
+ /* For sglist construction when adding commands to the virtqueue. */
+ struct scatterlist sg[];
+};
+
/* Driver instance state */
struct virtio_scsi {
- /* Protects sg[]. The lock hierarchy is sg_lock -> vq_lock. */
- spinlock_t sg_lock;
-
struct virtio_device *vdev;
+
struct virtio_scsi_vq ctrl_vq;
struct virtio_scsi_vq event_vq;
struct virtio_scsi_vq req_vq;
- /* For sglist construction when adding commands to the virtqueue. */
- struct scatterlist sg[];
+ struct virtio_scsi_target_state *tgt[];
};
static struct kmem_cache *virtscsi_cmd_cache;
@@ -230,25 +236,17 @@ static void virtscsi_map_sgl(struct scatterlist *sg, unsigned int *p_idx,
* @req_size : size of the request buffer
* @resp_size : size of the response buffer
*
- * Called with vq_lock held.
+ * Called with tgt_lock held.
*/
-static void virtscsi_map_cmd(struct virtio_scsi *vscsi,
+static void virtscsi_map_cmd(struct virtio_scsi_target_state *tgt,
struct virtio_scsi_cmd *cmd,
unsigned *out_num, unsigned *in_num,
size_t req_size, size_t resp_size)
{
struct scsi_cmnd *sc = cmd->sc;
- struct scatterlist *sg = vscsi->sg;
+ struct scatterlist *sg = tgt->sg;
unsigned int idx = 0;
- if (sc) {
- struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
- BUG_ON(scsi_sg_count(sc) > shost->sg_tablesize);
-
- /* TODO: check feature bit and fail if unsupported? */
- BUG_ON(sc->sc_data_direction == DMA_BIDIRECTIONAL);
- }
-
/* Request header. */
sg_set_buf(&sg[idx++], &cmd->req, req_size);
@@ -268,7 +266,8 @@ static void virtscsi_map_cmd(struct virtio_scsi *vscsi,
*in_num = idx - *out_num;
}
-static int virtscsi_kick_cmd(struct virtio_scsi *vscsi, struct virtio_scsi_vq *vq,
+static int virtscsi_kick_cmd(struct virtio_scsi_target_state *tgt,
+ struct virtio_scsi_vq *vq,
struct virtio_scsi_cmd *cmd,
size_t req_size, size_t resp_size, gfp_t gfp)
{
@@ -276,12 +275,12 @@ static int virtscsi_kick_cmd(struct virtio_scsi *vscsi, struct virtio_scsi_vq *v
unsigned long flags;
int ret;
- spin_lock_irqsave(&vscsi->sg_lock, flags);
- virtscsi_map_cmd(vscsi, cmd, &out_num, &in_num, req_size, resp_size);
+ spin_lock_irqsave(&tgt->tgt_lock, flags);
+ virtscsi_map_cmd(tgt, cmd, &out_num, &in_num, req_size, resp_size);
spin_lock(&vq->vq_lock);
- ret = virtqueue_add_buf(vq->vq, vscsi->sg, out_num, in_num, cmd, gfp);
- spin_unlock(&vscsi->sg_lock);
+ ret = virtqueue_add_buf(vq->vq, tgt->sg, out_num, in_num, cmd, gfp);
+ spin_unlock(&tgt->tgt_lock);
if (ret >= 0)
ret = virtqueue_kick_prepare(vq->vq);
@@ -295,9 +294,16 @@ static int virtscsi_kick_cmd(struct virtio_scsi *vscsi, struct virtio_scsi_vq *v
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 = vscsi->tgt[sc->device->id];
struct virtio_scsi_cmd *cmd;
int ret;
+ struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
+ BUG_ON(scsi_sg_count(sc) > shost->sg_tablesize);
+
+ /* TODO: check feature bit and fail if unsupported? */
+ BUG_ON(sc->sc_data_direction == DMA_BIDIRECTIONAL);
+
dev_dbg(&sc->device->sdev_gendev,
"cmd %p CDB: %#02x\n", sc, sc->cmnd[0]);
@@ -322,7 +328,7 @@ static int virtscsi_queuecommand(struct Scsi_Host *sh, struct scsi_cmnd *sc)
BUG_ON(sc->cmd_len > VIRTIO_SCSI_CDB_SIZE);
memcpy(cmd->req.cmd.cdb, sc->cmnd, sc->cmd_len);
- if (virtscsi_kick_cmd(vscsi, &vscsi->req_vq, cmd,
+ if (virtscsi_kick_cmd(tgt, &vscsi->req_vq, cmd,
sizeof cmd->req.cmd, sizeof cmd->resp.cmd,
GFP_ATOMIC) >= 0)
ret = 0;
@@ -334,10 +340,11 @@ out:
static int virtscsi_tmf(struct virtio_scsi *vscsi, struct virtio_scsi_cmd *cmd)
{
DECLARE_COMPLETION_ONSTACK(comp);
+ struct virtio_scsi_target_state *tgt = vscsi->tgt[cmd->sc->device->id];
int ret = FAILED;
cmd->comp = ∁
- if (virtscsi_kick_cmd(vscsi, &vscsi->ctrl_vq, cmd,
+ if (virtscsi_kick_cmd(tgt, &vscsi->ctrl_vq, cmd,
sizeof cmd->req.tmf, sizeof cmd->resp.tmf,
GFP_NOIO) < 0)
goto out;
@@ -437,11 +444,49 @@ static void virtscsi_init_vq(struct virtio_scsi_vq *virtscsi_vq,
virtscsi_vq->vq = vq;
}
+static struct virtio_scsi_target_state *virtscsi_alloc_tgt(
+ struct virtio_device *vdev, int sg_elems)
+{
+ struct virtio_scsi_target_state *tgt;
+ gfp_t gfp_mask = GFP_KERNEL;
+
+ /* We need extra sg elements at head and tail. */
+ tgt = kmalloc(sizeof(*tgt) + sizeof(tgt->sg[0]) * (sg_elems + 2),
+ gfp_mask);
+
+ if (!tgt)
+ return NULL;
+
+ spin_lock_init(&tgt->tgt_lock);
+ sg_init_table(tgt->sg, sg_elems + 2);
+ return tgt;
+}
+
+static void virtscsi_remove_vqs(struct virtio_device *vdev)
+{
+ struct Scsi_Host *sh = virtio_scsi_host(vdev);
+ struct virtio_scsi *vscsi = shost_priv(sh);
+ u32 i, num_targets;
+
+ /* Stop all the virtqueues. */
+ vdev->config->reset(vdev);
+
+ num_targets = sh->max_id;
+ for (i = 0; i < num_targets; i++) {
+ kfree(vscsi->tgt[i]);
+ vscsi->tgt[i] = NULL;
+ }
+
+ vdev->config->del_vqs(vdev);
+}
+
static int virtscsi_init(struct virtio_device *vdev,
- struct virtio_scsi *vscsi)
+ struct virtio_scsi *vscsi, int num_targets)
{
int err;
struct virtqueue *vqs[3];
+ u32 i, sg_elems;
+
vq_callback_t *callbacks[] = {
virtscsi_ctrl_done,
virtscsi_event_done,
@@ -464,7 +509,23 @@ static int virtscsi_init(struct virtio_device *vdev,
virtscsi_config_set(vdev, cdb_size, VIRTIO_SCSI_CDB_SIZE);
virtscsi_config_set(vdev, sense_size, VIRTIO_SCSI_SENSE_SIZE);
- return 0;
+
+ /* We need to know how many segments before we allocate. */
+ sg_elems = virtscsi_config_get(vdev, seg_max) ?: 1;
+
+ for (i = 0; i < num_targets; i++) {
+ vscsi->tgt[i] = virtscsi_alloc_tgt(vdev, sg_elems);
+ if (!vscsi->tgt[i]) {
+ err = -ENOMEM;
+ goto out;
+ }
+ }
+ err = 0;
+
+out:
+ if (err)
+ virtscsi_remove_vqs(vdev);
+ return err;
}
static int __devinit virtscsi_probe(struct virtio_device *vdev)
@@ -472,31 +533,25 @@ static int __devinit virtscsi_probe(struct virtio_device *vdev)
struct Scsi_Host *shost;
struct virtio_scsi *vscsi;
int err;
- u32 sg_elems;
+ u32 sg_elems, num_targets;
u32 cmd_per_lun;
- /* We need to know how many segments before we allocate.
- * We need an extra sg elements at head and tail.
- */
- sg_elems = virtscsi_config_get(vdev, seg_max) ?: 1;
-
/* Allocate memory and link the structs together. */
+ num_targets = virtscsi_config_get(vdev, max_target) + 1;
shost = scsi_host_alloc(&virtscsi_host_template,
- sizeof(*vscsi) + sizeof(vscsi->sg[0]) * (sg_elems + 2));
+ sizeof(*vscsi)
+ + num_targets * sizeof(struct virtio_scsi_target_state));
if (!shost)
return -ENOMEM;
+ sg_elems = virtscsi_config_get(vdev, seg_max) ?: 1;
shost->sg_tablesize = sg_elems;
vscsi = shost_priv(shost);
vscsi->vdev = vdev;
vdev->priv = shost;
- /* Random initializations. */
- spin_lock_init(&vscsi->sg_lock);
- sg_init_table(vscsi->sg, sg_elems + 2);
-
- err = virtscsi_init(vdev, vscsi);
+ err = virtscsi_init(vdev, vscsi, num_targets);
if (err)
goto virtscsi_init_failed;
@@ -504,7 +559,7 @@ static int __devinit virtscsi_probe(struct virtio_device *vdev)
shost->cmd_per_lun = min_t(u32, cmd_per_lun, shost->can_queue);
shost->max_sectors = virtscsi_config_get(vdev, max_sectors) ?: 0xFFFF;
shost->max_lun = virtscsi_config_get(vdev, max_lun) + 1;
- shost->max_id = virtscsi_config_get(vdev, max_target) + 1;
+ shost->max_id = num_targets;
shost->max_channel = 0;
shost->max_cmd_len = VIRTIO_SCSI_CDB_SIZE;
err = scsi_add_host(shost, &vdev->dev);
@@ -522,14 +577,6 @@ virtscsi_init_failed:
return err;
}
-static void virtscsi_remove_vqs(struct virtio_device *vdev)
-{
- /* Stop all the virtqueues. */
- vdev->config->reset(vdev);
-
- vdev->config->del_vqs(vdev);
-}
-
static void __devexit virtscsi_remove(struct virtio_device *vdev)
{
struct Scsi_Host *shost = virtio_scsi_host(vdev);
@@ -552,7 +599,7 @@ static int virtscsi_restore(struct virtio_device *vdev)
struct Scsi_Host *sh = virtio_scsi_host(vdev);
struct virtio_scsi *vscsi = shost_priv(sh);
- return virtscsi_init(vdev, vscsi);
+ return virtscsi_init(vdev, vscsi, sh->max_id);
}
#endif
--
1.7.1
--
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