virtio-blk: use virtqueue_add_sgs on req path
(This is a respin of Paolo Bonzini's patch, but it calls
virtqueue_add_sgs() instead of his multi-part API).
This is similar to the previous patch, but a bit more radical
because the bio and req paths now share the buffer construction
code. Because the req path doesn't use vbr->sg, however, we
need to add a couple of arguments to __virtblk_add_req.
We also need to teach __virtblk_add_req how to build SCSI command
requests.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Reviewed-by: Asias He <asias@redhat.com>
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index cfbe39d..cc88b29 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -102,19 +102,40 @@
}
static int __virtblk_add_req(struct virtqueue *vq,
- struct virtblk_req *vbr)
+ struct virtblk_req *vbr,
+ struct scatterlist *data_sg,
+ unsigned data_nents)
{
- struct scatterlist hdr, status, *sgs[3];
+ struct scatterlist hdr, status, cmd, sense, inhdr, *sgs[6];
unsigned int num_out = 0, num_in = 0;
+ int type = vbr->out_hdr.type & ~VIRTIO_BLK_T_OUT;
sg_init_one(&hdr, &vbr->out_hdr, sizeof(vbr->out_hdr));
sgs[num_out++] = &hdr;
- if (vbr->nents) {
+ /*
+ * If this is a packet command we need a couple of additional headers.
+ * Behind the normal outhdr we put a segment with the scsi command
+ * block, and before the normal inhdr we put the sense data and the
+ * inhdr with additional status information.
+ */
+ if (type == VIRTIO_BLK_T_SCSI_CMD) {
+ sg_init_one(&cmd, vbr->req->cmd, vbr->req->cmd_len);
+ sgs[num_out++] = &cmd;
+ }
+
+ if (data_nents) {
if (vbr->out_hdr.type & VIRTIO_BLK_T_OUT)
- sgs[num_out++] = vbr->sg;
+ sgs[num_out++] = data_sg;
else
- sgs[num_out + num_in++] = vbr->sg;
+ sgs[num_out + num_in++] = data_sg;
+ }
+
+ if (type == VIRTIO_BLK_T_SCSI_CMD) {
+ sg_init_one(&sense, vbr->req->sense, SCSI_SENSE_BUFFERSIZE);
+ sgs[num_out + num_in++] = &sense;
+ sg_init_one(&inhdr, &vbr->in_hdr, sizeof(vbr->in_hdr));
+ sgs[num_out + num_in++] = &inhdr;
}
sg_init_one(&status, &vbr->status, sizeof(vbr->status));
@@ -130,7 +151,8 @@
int ret;
spin_lock_irq(vblk->disk->queue->queue_lock);
- while (unlikely((ret = __virtblk_add_req(vblk->vq, vbr)) < 0)) {
+ while (unlikely((ret = __virtblk_add_req(vblk->vq, vbr, vbr->sg,
+ vbr->nents)) < 0)) {
prepare_to_wait_exclusive(&vblk->queue_wait, &wait,
TASK_UNINTERRUPTIBLE);
@@ -283,7 +305,7 @@
static bool do_req(struct request_queue *q, struct virtio_blk *vblk,
struct request *req)
{
- unsigned long num, out = 0, in = 0;
+ unsigned int num;
struct virtblk_req *vbr;
vbr = virtblk_alloc_req(vblk, GFP_ATOMIC);
@@ -320,40 +342,15 @@
}
}
- sg_set_buf(&vblk->sg[out++], &vbr->out_hdr, sizeof(vbr->out_hdr));
-
- /*
- * If this is a packet command we need a couple of additional headers.
- * Behind the normal outhdr we put a segment with the scsi command
- * block, and before the normal inhdr we put the sense data and the
- * inhdr with additional status information before the normal inhdr.
- */
- if (vbr->req->cmd_type == REQ_TYPE_BLOCK_PC)
- sg_set_buf(&vblk->sg[out++], vbr->req->cmd, vbr->req->cmd_len);
-
- num = blk_rq_map_sg(q, vbr->req, vblk->sg + out);
-
- if (vbr->req->cmd_type == REQ_TYPE_BLOCK_PC) {
- sg_set_buf(&vblk->sg[num + out + in++], vbr->req->sense, SCSI_SENSE_BUFFERSIZE);
- sg_set_buf(&vblk->sg[num + out + in++], &vbr->in_hdr,
- sizeof(vbr->in_hdr));
- }
-
- sg_set_buf(&vblk->sg[num + out + in++], &vbr->status,
- sizeof(vbr->status));
-
+ num = blk_rq_map_sg(q, vbr->req, vblk->sg);
if (num) {
- if (rq_data_dir(vbr->req) == WRITE) {
+ if (rq_data_dir(vbr->req) == WRITE)
vbr->out_hdr.type |= VIRTIO_BLK_T_OUT;
- out += num;
- } else {
+ else
vbr->out_hdr.type |= VIRTIO_BLK_T_IN;
- in += num;
- }
}
- if (virtqueue_add_buf(vblk->vq, vblk->sg, out, in, vbr,
- GFP_ATOMIC) < 0) {
+ if (__virtblk_add_req(vblk->vq, vbr, vblk->sg, num) < 0) {
mempool_free(vbr, vblk->pool);
return false;
}