If we want to do bio-based I/O in virtio-blk we have to implement reading
the serial attribute ourselves. Do that and also prepare struct virtblk_req
for dealing with different types of requests.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Index: linux-2.6/drivers/block/virtio_blk.c
===================================================================
--- linux-2.6.orig/drivers/block/virtio_blk.c 2011-10-03 20:32:12.997713070 +0200
+++ linux-2.6/drivers/block/virtio_blk.c 2011-10-03 20:37:28.836714193 +0200
@@ -38,12 +38,42 @@ struct virtio_blk
struct virtblk_req
{
- struct request *req;
+ void *private;
struct virtio_blk_outhdr out_hdr;
struct virtio_scsi_inhdr in_hdr;
+ u8 kind;
+#define VIRTIO_BLK_REQUEST 0x00
+#define VIRTIO_BLK_INTERNAL 0x01
u8 status;
};
+static inline int virtblk_result(struct virtblk_req *vbr)
+{
+ switch (vbr->status) {
+ case VIRTIO_BLK_S_OK:
+ return 0;
+ case VIRTIO_BLK_S_UNSUPP:
+ return -ENOTTY;
+ default:
+ return -EIO;
+ }
+}
+
+static void virtblk_request_done(struct virtio_blk *vblk,
+ struct virtblk_req *vbr)
+{
+ struct request *req = vbr->private;
+
+ if (req->cmd_type == REQ_TYPE_BLOCK_PC) {
+ req->resid_len = vbr->in_hdr.residual;
+ req->sense_len = vbr->in_hdr.sense_len;
+ req->errors = vbr->in_hdr.errors;
+ }
+
+ __blk_end_request_all(req, virtblk_result(vbr));
+ mempool_free(vbr, vblk->pool);
+}
+
static void blk_done(struct virtqueue *vq)
{
struct virtio_blk *vblk = vq->vdev->priv;
@@ -53,35 +83,16 @@ static void blk_done(struct virtqueue *v
spin_lock_irqsave(&vblk->lock, flags);
while ((vbr = virtqueue_get_buf(vblk->vq, &len)) != NULL) {
- int error;
-
- switch (vbr->status) {
- case VIRTIO_BLK_S_OK:
- error = 0;
- break;
- case VIRTIO_BLK_S_UNSUPP:
- error = -ENOTTY;
- break;
- default:
- error = -EIO;
- break;
- }
-
- switch (vbr->req->cmd_type) {
- case REQ_TYPE_BLOCK_PC:
- vbr->req->resid_len = vbr->in_hdr.residual;
- vbr->req->sense_len = vbr->in_hdr.sense_len;
- vbr->req->errors = vbr->in_hdr.errors;
+ switch (vbr->kind) {
+ case VIRTIO_BLK_REQUEST:
+ virtblk_request_done(vblk, vbr);
break;
- case REQ_TYPE_SPECIAL:
- vbr->req->errors = (error != 0);
+ case VIRTIO_BLK_INTERNAL:
+ complete(vbr->private);
break;
default:
- break;
+ BUG();
}
-
- __blk_end_request_all(vbr->req, error);
- mempool_free(vbr, vblk->pool);
}
/* In case queue is stopped waiting for more buffers. */
blk_start_queue(vblk->disk->queue);
@@ -99,28 +110,24 @@ static bool do_req(struct request_queue
/* When another request finishes we'll try again. */
return false;
- vbr->req = req;
+ vbr->private = req;
+ vbr->kind = VIRTIO_BLK_REQUEST;
if (req->cmd_flags & REQ_FLUSH) {
vbr->out_hdr.type = VIRTIO_BLK_T_FLUSH;
vbr->out_hdr.sector = 0;
- vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
+ vbr->out_hdr.ioprio = req_get_ioprio(req);
} else {
switch (req->cmd_type) {
case REQ_TYPE_FS:
vbr->out_hdr.type = 0;
- vbr->out_hdr.sector = blk_rq_pos(vbr->req);
- vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
+ vbr->out_hdr.sector = blk_rq_pos(req);
+ vbr->out_hdr.ioprio = req_get_ioprio(req);
break;
case REQ_TYPE_BLOCK_PC:
vbr->out_hdr.type = VIRTIO_BLK_T_SCSI_CMD;
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);
+ vbr->out_hdr.ioprio = req_get_ioprio(req);
break;
default:
/* We don't put anything else in the queue. */
@@ -136,13 +143,14 @@ static bool do_req(struct request_queue
* 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);
+ if (req->cmd_type == REQ_TYPE_BLOCK_PC)
+ sg_set_buf(&vblk->sg[out++], req->cmd, req->cmd_len);
- num = blk_rq_map_sg(q, vbr->req, vblk->sg + out);
+ num = blk_rq_map_sg(q, 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);
+ if (req->cmd_type == REQ_TYPE_BLOCK_PC) {
+ sg_set_buf(&vblk->sg[num + out + in++], req->sense,
+ SCSI_SENSE_BUFFERSIZE);
sg_set_buf(&vblk->sg[num + out + in++], &vbr->in_hdr,
sizeof(vbr->in_hdr));
}
@@ -151,7 +159,7 @@ static bool do_req(struct request_queue
sizeof(vbr->status));
if (num) {
- if (rq_data_dir(vbr->req) == WRITE) {
+ if (rq_data_dir(req) == WRITE) {
vbr->out_hdr.type |= VIRTIO_BLK_T_OUT;
out += num;
} else {
@@ -196,26 +204,39 @@ static void do_virtblk_request(struct re
static int virtblk_get_id(struct gendisk *disk, char *id_str)
{
struct virtio_blk *vblk = disk->private_data;
- struct request *req;
- struct bio *bio;
- int err;
-
- 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;
- err = blk_execute_rq(vblk->disk->queue, vblk->disk, req, false);
- blk_put_request(req);
+ struct virtblk_req *vbr;
+ DECLARE_COMPLETION_ONSTACK(done);
+ int error;
- return err;
+ vbr = kmalloc(sizeof(*vbr), GFP_KERNEL);
+ if (!vbr)
+ return -ENOMEM;
+ vbr->private = &done;
+ vbr->kind = VIRTIO_BLK_INTERNAL;
+
+ vbr->out_hdr.type = VIRTIO_BLK_T_GET_ID | VIRTIO_BLK_T_IN;
+ vbr->out_hdr.sector = 0;
+ vbr->out_hdr.ioprio = 0;
+
+ sg_set_buf(&vblk->sg[0], &vbr->out_hdr, sizeof(vbr->out_hdr));
+ sg_set_buf(&vblk->sg[1], id_str, VIRTIO_BLK_ID_BYTES);
+ sg_set_buf(&vblk->sg[2], &vbr->status, sizeof(vbr->status));
+
+ spin_lock_irq(&vblk->lock);
+ if (virtqueue_add_buf(vblk->vq, vblk->sg, 1, 2, vbr) < 0) {
+ spin_unlock_irq(&vblk->lock);
+ /* XXX: eventuall wait for free space */
+ error = -EBUSY;
+ goto out_free;
+ }
+ virtqueue_kick(vblk->vq);
+ spin_unlock_irq(&vblk->lock);
+
+ wait_for_completion(&done);
+ error = virtblk_result(vbr);
+out_free:
+ kfree(vbr);
+ return error;
}
static int virtblk_ioctl(struct block_device *bdev, fmode_t mode,
--
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