Add virtio disk identification support

Add virtio-blk device id (s/n) support via virtio request.

Signed-off-by: john cooper <john.cooper@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 2138a7ae050c10c44bdba1608f441a7811ca1a22..759dee8330ac4fcbcd108e1bdb6b1088d2a8ce4e 100644 (file)
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -70,6 +70,8 @@ static void blk_done(struct virtqueue *vq)
                        vbr->req->sense_len = vbr->in_hdr.sense_len;
                        vbr->req->errors = vbr->in_hdr.errors;
                }
+               if (blk_special_request(vbr->req))
+                       vbr->req->errors = (error != 0);
 
                __blk_end_request_all(vbr->req, error);
                list_del(&vbr->list);
@@ -103,6 +105,11 @@ static bool do_req(struct request_queue *q, struct virtio_blk *vblk,
                vbr->out_hdr.sector = 0;
                vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
                break;
+       case REQ_TYPE_SPECIAL:
+               vbr->out_hdr.type = VIRTIO_BLK_T_GET_ID;
+               vbr->out_hdr.sector = 0;
+               vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
+               break;
        case REQ_TYPE_LINUX_BLOCK:
                if (req->cmd[0] == REQ_LB_OP_FLUSH) {
                        vbr->out_hdr.type = VIRTIO_BLK_T_FLUSH;
@@ -189,6 +196,29 @@ static void virtblk_prepare_flush(struct request_queue *q, struct request *req)
        req->cmd[0] = REQ_LB_OP_FLUSH;
 }
 
+/* return id (s/n) string for *disk to *id_str
+ */
+static int virtblk_get_id(struct gendisk *disk, char *id_str)
+{
+       struct virtio_blk *vblk = disk->private_data;
+       struct request *req;
+       struct bio *bio;
+
+       bio = bio_map_kern(vblk->disk->queue, id_str, VIRTIO_BLK_ID_BYTES,
+                          GFP_KERNEL);
+       if (IS_ERR(bio))
+               return PTR_ERR(bio);
+
+       req = blk_make_request(vblk->disk->queue, bio, GFP_KERNEL);
+       if (IS_ERR(req)) {
+               bio_put(bio);
+               return PTR_ERR(req);
+       }
+
+       req->cmd_type = REQ_TYPE_SPECIAL;
+       return blk_execute_rq(vblk->disk->queue, vblk->disk, req, false);
+}
+
 static int virtblk_ioctl(struct block_device *bdev, fmode_t mode,
                         unsigned cmd, unsigned long data)
 {

diff --git a/include/linux/virtio_blk.h b/include/linux/virtio_blk.h
index e52029e98919bb38401dd1848de418277ba271a9..167720d695ed00bb94b9174381de80f13fd6d009 100644 (file)
--- a/include/linux/virtio_blk.h
+++ b/include/linux/virtio_blk.h
@@ -17,6 +17,8 @@
 #define VIRTIO_BLK_F_FLUSH     9       /* Cache flush command support */
 #define VIRTIO_BLK_F_TOPOLOGY  10      /* Topology information is available */
 
+#define VIRTIO_BLK_ID_BYTES    20      /* ID string length */
+
 struct virtio_blk_config {
        /* The capacity (in 512-byte sectors). */
        __u64 capacity;
@@ -67,6 +69,9 @@ struct virtio_blk_config {
 /* Cache flush command */
 #define VIRTIO_BLK_T_FLUSH     4
 
+/* Get device ID command */
+#define VIRTIO_BLK_T_GET_ID    8
+
 /* Barrier before this op. */
 #define VIRTIO_BLK_T_BARRIER   0x80000000