virtio_blk: SG_IO passthru support
Add support for SG_IO passthru to virtio_blk. We add the scsi command
block after the normal outhdr, and the scsi inhdr with full status
information aswell as the sense buffer before the regular inhdr.
[hch: forward ported, added the VIRTIO_BLK_F_SCSI flags, some comments
and tested the whole beast]
[axboe: updated to use ->resid and not dual-path the byte count]
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (+ checkpatch.pl tweak)
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index dfe9ee5..62275db 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -37,6 +37,7 @@
struct list_head list;
struct request *req;
struct virtio_blk_outhdr out_hdr;
+ struct virtio_scsi_inhdr in_hdr;
u8 status;
};
@@ -49,7 +50,9 @@
spin_lock_irqsave(&vblk->lock, flags);
while ((vbr = vblk->vq->vq_ops->get_buf(vblk->vq, &len)) != NULL) {
+ unsigned int nr_bytes;
int error;
+
switch (vbr->status) {
case VIRTIO_BLK_S_OK:
error = 0;
@@ -62,6 +65,12 @@
break;
}
+ if (blk_pc_request(vbr->req)) {
+ vbr->req->resid_len = vbr->in_hdr.residual;
+ vbr->req->sense_len = vbr->in_hdr.sense_len;
+ vbr->req->errors = vbr->in_hdr.errors;
+ }
+
__blk_end_request_all(vbr->req, error);
list_del(&vbr->list);
mempool_free(vbr, vblk->pool);
@@ -74,7 +83,7 @@
static bool do_req(struct request_queue *q, struct virtio_blk *vblk,
struct request *req)
{
- unsigned long num, out, in;
+ unsigned long num, out = 0, in = 0;
struct virtblk_req *vbr;
vbr = mempool_alloc(vblk->pool, GFP_ATOMIC);
@@ -99,18 +108,36 @@
if (blk_barrier_rq(vbr->req))
vbr->out_hdr.type |= VIRTIO_BLK_T_BARRIER;
- sg_set_buf(&vblk->sg[0], &vbr->out_hdr, sizeof(vbr->out_hdr));
- num = blk_rq_map_sg(q, vbr->req, vblk->sg+1);
- sg_set_buf(&vblk->sg[num+1], &vbr->status, sizeof(vbr->status));
+ sg_set_buf(&vblk->sg[out++], &vbr->out_hdr, sizeof(vbr->out_hdr));
- if (rq_data_dir(vbr->req) == WRITE) {
- vbr->out_hdr.type |= VIRTIO_BLK_T_OUT;
- out = 1 + num;
- in = 1;
- } else {
- vbr->out_hdr.type |= VIRTIO_BLK_T_IN;
- out = 1;
- in = 1 + num;
+ /*
+ * 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 (blk_pc_request(vbr->req))
+ 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 (blk_pc_request(vbr->req)) {
+ sg_set_buf(&vblk->sg[num + out + in++], vbr->req->sense, 96);
+ 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));
+
+ if (num) {
+ if (rq_data_dir(vbr->req) == WRITE) {
+ vbr->out_hdr.type |= VIRTIO_BLK_T_OUT;
+ out += num;
+ } else {
+ vbr->out_hdr.type |= VIRTIO_BLK_T_IN;
+ in += num;
+ }
}
if (vblk->vq->vq_ops->add_buf(vblk->vq, vblk->sg, out, in, vbr)) {
@@ -148,8 +175,16 @@
static int virtblk_ioctl(struct block_device *bdev, fmode_t mode,
unsigned cmd, unsigned long data)
{
- return scsi_cmd_ioctl(bdev->bd_disk->queue,
- bdev->bd_disk, mode, cmd,
+ struct gendisk *disk = bdev->bd_disk;
+ struct virtio_blk *vblk = disk->private_data;
+
+ /*
+ * Only allow the generic SCSI ioctls if the host can support it.
+ */
+ if (!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_SCSI))
+ return -ENOIOCTLCMD;
+
+ return scsi_cmd_ioctl(disk->queue, disk, mode, cmd,
(void __user *)data);
}
@@ -356,6 +391,7 @@
static unsigned int features[] = {
VIRTIO_BLK_F_BARRIER, VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX,
VIRTIO_BLK_F_GEOMETRY, VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE,
+ VIRTIO_BLK_F_SCSI,
};
static struct virtio_driver virtio_blk = {
diff --git a/include/linux/virtio_blk.h b/include/linux/virtio_blk.h
index 94c56d2..4dbcbc1 100644
--- a/include/linux/virtio_blk.h
+++ b/include/linux/virtio_blk.h
@@ -15,6 +15,7 @@
#define VIRTIO_BLK_F_GEOMETRY 4 /* Legacy geometry available */
#define VIRTIO_BLK_F_RO 5 /* Disk is read-only */
#define VIRTIO_BLK_F_BLK_SIZE 6 /* Block size of disk is available*/
+#define VIRTIO_BLK_F_SCSI 7 /* Supports scsi command passthru */
struct virtio_blk_config
{
@@ -55,6 +56,13 @@
__u64 sector;
};
+struct virtio_scsi_inhdr {
+ __u32 errors;
+ __u32 data_len;
+ __u32 sense_len;
+ __u32 residual;
+};
+
/* And this is the final byte of the write scatter-gather list. */
#define VIRTIO_BLK_S_OK 0
#define VIRTIO_BLK_S_IOERR 1