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Date: Wed, 30 Sep 2009 02:48:44 +0930
From: Rusty Russell <rusty@...tcorp.com.au>
To: linux-kernel@...r.kernel.org
Cc: Jens Axboe <axboe@...nel.dk>,
virtualization@...ts.linux-foundation.org,
john cooper <john.cooper@...hat.com>
Subject: [PATCH 3/4] virtio_blk: implement a request-based ID command, VIRTIO_BLK_T_GET_ID
This is fairly simple: we create a request pointing at the 1k kmalloc,
then just change the type so our do_req() knows to mark it as a GET_ID
for the server.
Seems to work here; the only issue is that the error didn't get passed
back from __blk_end_request_all to blk_execute_rq, so we set ->errors
to 1 on error.
Signed-off-by: Rusty Russell <rusty@...tcorp.com.au>
Cc: Jens Axboe <axboe@...nel.dk>
---
drivers/block/virtio_blk.c | 66 +++++++++++++++++++++++++++++++++++----------
include/linux/virtio_blk.h | 4 ++
2 files changed, 56 insertions(+), 14 deletions(-)
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -72,6 +72,8 @@ static void blk_done(struct virtqueue *v
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);
@@ -105,6 +107,11 @@ static bool do_req(struct request_queue
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;
@@ -201,29 +208,59 @@ struct virtio_blk_config_deprecated {
__u8 identify[VIRTIO_BLK_ID_BYTES];
} __attribute__((packed));
-static int virtblk_identify(struct gendisk *disk, void *argp)
+static int virtblk_identify_deprecated(struct virtio_blk *vblk, void *opaque)
+{
+ return virtio_config_buf(vblk->vdev, VIRTIO_BLK_F_IDENTIFY,
+ offsetof(struct virtio_blk_config_deprecated, identify), opaque,
+ VIRTIO_BLK_ID_BYTES);
+}
+
+static int virtblk_get_id(struct virtio_blk *vblk, void *opaque)
+{
+ struct request *req;
+ struct bio *bio;
+
+ bio = bio_map_kern(vblk->disk->queue, opaque, 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);
+ }
+
+ /* This is actually a special request. */
+ req->cmd_type = REQ_TYPE_SPECIAL;
+ return blk_execute_rq(vblk->disk->queue, vblk->disk, req, false);
+}
+
+static int virtblk_identify(struct gendisk *disk, void __user *argp)
{
struct virtio_blk *vblk = disk->private_data;
void *opaque;
- int err = -ENOMEM;
+ int err;
opaque = kmalloc(VIRTIO_BLK_ID_BYTES, GFP_KERNEL);
if (!opaque)
- goto out;
+ return -ENOMEM;
- err = virtio_config_buf(vblk->vdev, VIRTIO_BLK_F_IDENTIFY,
- offsetof(struct virtio_blk_config_deprecated, identify), opaque,
- VIRTIO_BLK_ID_BYTES);
+ /* The modern way. */
+ if (virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_GET_ID))
+ err = virtblk_get_id(vblk, opaque);
+ /* The deprecated way. */
+ else if (virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_IDENTIFY))
+ err = virtblk_identify_deprecated(vblk, opaque);
+ /* No way. */
+ else
+ err = -ENOTTY;
- if (err)
- goto out_kfree;
+ if (!err)
+ if (copy_to_user(argp, opaque, VIRTIO_BLK_ID_BYTES))
+ err = -EFAULT;
- if (copy_to_user(argp, opaque, VIRTIO_BLK_ID_BYTES))
- err = -EFAULT;
-
-out_kfree:
kfree(opaque);
-out:
return err;
}
@@ -460,7 +497,8 @@ static struct virtio_device_id id_table[
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, VIRTIO_BLK_F_IDENTIFY, VIRTIO_BLK_F_FLUSH
+ VIRTIO_BLK_F_SCSI, VIRTIO_BLK_F_IDENTIFY, VIRTIO_BLK_F_FLUSH,
+ VIRTIO_BLK_F_GET_ID
};
/*
diff --git a/include/linux/virtio_blk.h b/include/linux/virtio_blk.h
--- a/include/linux/virtio_blk.h
+++ b/include/linux/virtio_blk.h
@@ -15,6 +15,7 @@
#define VIRTIO_BLK_F_SCSI 7 /* Supports scsi command passthru */
#define VIRTIO_BLK_F_IDENTIFY 8 /* ATA IDENTIFY support (deprecated) */
#define VIRTIO_BLK_F_FLUSH 9 /* Cache flush command support */
+#define VIRTIO_BLK_F_GET_ID 10 /* VIRTIO_BLK_T_GET_ID support */
#define VIRTIO_BLK_ID_BYTES (sizeof(__u16[256])) /* IDENTIFY DATA */
@@ -65,6 +66,9 @@ struct virtio_blk_config {
/* Cache flush command */
#define VIRTIO_BLK_T_FLUSH 4
+/* Get ID command */
+#define VIRTIO_BLK_T_GET_ID 8
+
/* Barrier before this op. */
#define VIRTIO_BLK_T_BARRIER 0x80000000
--
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