[SCSI] 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@redhat.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
This commit is contained in:
Paolo Bonzini
James Bottomley
parent
bce750b163
commit
2bd37f0fde
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@ -50,18 +50,24 @@ struct virtio_scsi_vq {
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struct virtqueue *vq;
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};
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/* Per-target queue state */
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struct virtio_scsi_target_state {
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/* Protects sg. Lock hierarchy is tgt_lock -> vq_lock. */
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spinlock_t tgt_lock;
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/* For sglist construction when adding commands to the virtqueue. */
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struct scatterlist sg[];
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};
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/* Driver instance state */
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struct virtio_scsi {
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/* Protects sg[]. The lock hierarchy is sg_lock -> vq_lock. */
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spinlock_t sg_lock;
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struct virtio_device *vdev;
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struct virtio_scsi_vq ctrl_vq;
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struct virtio_scsi_vq event_vq;
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struct virtio_scsi_vq req_vq;
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/* For sglist construction when adding commands to the virtqueue. */
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struct scatterlist sg[];
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struct virtio_scsi_target_state *tgt[];
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};
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static struct kmem_cache *virtscsi_cmd_cache;
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@ -230,25 +236,17 @@ static void virtscsi_map_sgl(struct scatterlist *sg, unsigned int *p_idx,
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* @req_size : size of the request buffer
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* @resp_size : size of the response buffer
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*
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* Called with vq_lock held.
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* Called with tgt_lock held.
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*/
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static void virtscsi_map_cmd(struct virtio_scsi *vscsi,
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static void virtscsi_map_cmd(struct virtio_scsi_target_state *tgt,
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struct virtio_scsi_cmd *cmd,
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unsigned *out_num, unsigned *in_num,
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size_t req_size, size_t resp_size)
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{
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struct scsi_cmnd *sc = cmd->sc;
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struct scatterlist *sg = vscsi->sg;
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struct scatterlist *sg = tgt->sg;
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unsigned int idx = 0;
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if (sc) {
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struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
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BUG_ON(scsi_sg_count(sc) > shost->sg_tablesize);
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/* TODO: check feature bit and fail if unsupported? */
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BUG_ON(sc->sc_data_direction == DMA_BIDIRECTIONAL);
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}
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/* Request header. */
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sg_set_buf(&sg[idx++], &cmd->req, req_size);
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@ -268,7 +266,8 @@ static void virtscsi_map_cmd(struct virtio_scsi *vscsi,
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*in_num = idx - *out_num;
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}
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static int virtscsi_kick_cmd(struct virtio_scsi *vscsi, struct virtio_scsi_vq *vq,
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static int virtscsi_kick_cmd(struct virtio_scsi_target_state *tgt,
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struct virtio_scsi_vq *vq,
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struct virtio_scsi_cmd *cmd,
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size_t req_size, size_t resp_size, gfp_t gfp)
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{
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@ -276,12 +275,12 @@ static int virtscsi_kick_cmd(struct virtio_scsi *vscsi, struct virtio_scsi_vq *v
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unsigned long flags;
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int ret;
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spin_lock_irqsave(&vscsi->sg_lock, flags);
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virtscsi_map_cmd(vscsi, cmd, &out_num, &in_num, req_size, resp_size);
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spin_lock_irqsave(&tgt->tgt_lock, flags);
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virtscsi_map_cmd(tgt, cmd, &out_num, &in_num, req_size, resp_size);
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spin_lock(&vq->vq_lock);
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ret = virtqueue_add_buf(vq->vq, vscsi->sg, out_num, in_num, cmd, gfp);
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spin_unlock(&vscsi->sg_lock);
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ret = virtqueue_add_buf(vq->vq, tgt->sg, out_num, in_num, cmd, gfp);
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spin_unlock(&tgt->tgt_lock);
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if (ret >= 0)
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ret = virtqueue_kick_prepare(vq->vq);
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@ -295,9 +294,16 @@ static int virtscsi_kick_cmd(struct virtio_scsi *vscsi, struct virtio_scsi_vq *v
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static int virtscsi_queuecommand(struct Scsi_Host *sh, struct scsi_cmnd *sc)
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{
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struct virtio_scsi *vscsi = shost_priv(sh);
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struct virtio_scsi_target_state *tgt = vscsi->tgt[sc->device->id];
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struct virtio_scsi_cmd *cmd;
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int ret;
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struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
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BUG_ON(scsi_sg_count(sc) > shost->sg_tablesize);
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/* TODO: check feature bit and fail if unsupported? */
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BUG_ON(sc->sc_data_direction == DMA_BIDIRECTIONAL);
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dev_dbg(&sc->device->sdev_gendev,
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"cmd %p CDB: %#02x\n", sc, sc->cmnd[0]);
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@ -322,7 +328,7 @@ static int virtscsi_queuecommand(struct Scsi_Host *sh, struct scsi_cmnd *sc)
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BUG_ON(sc->cmd_len > VIRTIO_SCSI_CDB_SIZE);
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memcpy(cmd->req.cmd.cdb, sc->cmnd, sc->cmd_len);
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if (virtscsi_kick_cmd(vscsi, &vscsi->req_vq, cmd,
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if (virtscsi_kick_cmd(tgt, &vscsi->req_vq, cmd,
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sizeof cmd->req.cmd, sizeof cmd->resp.cmd,
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GFP_ATOMIC) >= 0)
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ret = 0;
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@ -334,10 +340,11 @@ out:
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static int virtscsi_tmf(struct virtio_scsi *vscsi, struct virtio_scsi_cmd *cmd)
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{
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DECLARE_COMPLETION_ONSTACK(comp);
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struct virtio_scsi_target_state *tgt = vscsi->tgt[cmd->sc->device->id];
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int ret = FAILED;
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cmd->comp = ∁
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if (virtscsi_kick_cmd(vscsi, &vscsi->ctrl_vq, cmd,
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if (virtscsi_kick_cmd(tgt, &vscsi->ctrl_vq, cmd,
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sizeof cmd->req.tmf, sizeof cmd->resp.tmf,
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GFP_NOIO) < 0)
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goto out;
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@ -437,11 +444,49 @@ static void virtscsi_init_vq(struct virtio_scsi_vq *virtscsi_vq,
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virtscsi_vq->vq = vq;
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}
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static struct virtio_scsi_target_state *virtscsi_alloc_tgt(
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struct virtio_device *vdev, int sg_elems)
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{
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struct virtio_scsi_target_state *tgt;
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gfp_t gfp_mask = GFP_KERNEL;
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/* We need extra sg elements at head and tail. */
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tgt = kmalloc(sizeof(*tgt) + sizeof(tgt->sg[0]) * (sg_elems + 2),
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gfp_mask);
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if (!tgt)
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return NULL;
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spin_lock_init(&tgt->tgt_lock);
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sg_init_table(tgt->sg, sg_elems + 2);
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return tgt;
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}
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static void virtscsi_remove_vqs(struct virtio_device *vdev)
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{
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struct Scsi_Host *sh = virtio_scsi_host(vdev);
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struct virtio_scsi *vscsi = shost_priv(sh);
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u32 i, num_targets;
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/* Stop all the virtqueues. */
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vdev->config->reset(vdev);
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num_targets = sh->max_id;
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for (i = 0; i < num_targets; i++) {
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kfree(vscsi->tgt[i]);
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vscsi->tgt[i] = NULL;
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}
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vdev->config->del_vqs(vdev);
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}
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static int virtscsi_init(struct virtio_device *vdev,
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struct virtio_scsi *vscsi)
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struct virtio_scsi *vscsi, int num_targets)
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{
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int err;
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struct virtqueue *vqs[3];
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u32 i, sg_elems;
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vq_callback_t *callbacks[] = {
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virtscsi_ctrl_done,
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virtscsi_event_done,
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@ -464,7 +509,23 @@ static int virtscsi_init(struct virtio_device *vdev,
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virtscsi_config_set(vdev, cdb_size, VIRTIO_SCSI_CDB_SIZE);
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virtscsi_config_set(vdev, sense_size, VIRTIO_SCSI_SENSE_SIZE);
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return 0;
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/* We need to know how many segments before we allocate. */
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sg_elems = virtscsi_config_get(vdev, seg_max) ?: 1;
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for (i = 0; i < num_targets; i++) {
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vscsi->tgt[i] = virtscsi_alloc_tgt(vdev, sg_elems);
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if (!vscsi->tgt[i]) {
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err = -ENOMEM;
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goto out;
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}
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}
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err = 0;
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out:
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if (err)
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virtscsi_remove_vqs(vdev);
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return err;
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}
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static int __devinit virtscsi_probe(struct virtio_device *vdev)
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@ -472,31 +533,25 @@ static int __devinit virtscsi_probe(struct virtio_device *vdev)
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struct Scsi_Host *shost;
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struct virtio_scsi *vscsi;
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int err;
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u32 sg_elems;
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u32 sg_elems, num_targets;
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u32 cmd_per_lun;
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/* We need to know how many segments before we allocate.
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* We need an extra sg elements at head and tail.
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*/
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sg_elems = virtscsi_config_get(vdev, seg_max) ?: 1;
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/* Allocate memory and link the structs together. */
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num_targets = virtscsi_config_get(vdev, max_target) + 1;
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shost = scsi_host_alloc(&virtscsi_host_template,
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sizeof(*vscsi) + sizeof(vscsi->sg[0]) * (sg_elems + 2));
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sizeof(*vscsi)
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+ num_targets * sizeof(struct virtio_scsi_target_state));
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if (!shost)
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return -ENOMEM;
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sg_elems = virtscsi_config_get(vdev, seg_max) ?: 1;
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shost->sg_tablesize = sg_elems;
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vscsi = shost_priv(shost);
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vscsi->vdev = vdev;
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vdev->priv = shost;
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/* Random initializations. */
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spin_lock_init(&vscsi->sg_lock);
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sg_init_table(vscsi->sg, sg_elems + 2);
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err = virtscsi_init(vdev, vscsi);
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err = virtscsi_init(vdev, vscsi, num_targets);
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if (err)
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goto virtscsi_init_failed;
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@ -504,7 +559,7 @@ static int __devinit virtscsi_probe(struct virtio_device *vdev)
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shost->cmd_per_lun = min_t(u32, cmd_per_lun, shost->can_queue);
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shost->max_sectors = virtscsi_config_get(vdev, max_sectors) ?: 0xFFFF;
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shost->max_lun = virtscsi_config_get(vdev, max_lun) + 1;
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shost->max_id = virtscsi_config_get(vdev, max_target) + 1;
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shost->max_id = num_targets;
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shost->max_channel = 0;
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shost->max_cmd_len = VIRTIO_SCSI_CDB_SIZE;
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err = scsi_add_host(shost, &vdev->dev);
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@ -522,14 +577,6 @@ virtscsi_init_failed:
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return err;
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}
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static void virtscsi_remove_vqs(struct virtio_device *vdev)
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{
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/* Stop all the virtqueues. */
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vdev->config->reset(vdev);
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vdev->config->del_vqs(vdev);
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}
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static void __devexit virtscsi_remove(struct virtio_device *vdev)
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{
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struct Scsi_Host *shost = virtio_scsi_host(vdev);
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@ -552,7 +599,7 @@ static int virtscsi_restore(struct virtio_device *vdev)
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struct Scsi_Host *sh = virtio_scsi_host(vdev);
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struct virtio_scsi *vscsi = shost_priv(sh);
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return virtscsi_init(vdev, vscsi);
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return virtscsi_init(vdev, vscsi, sh->max_id);
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}
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#endif
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