[Qemu-devel] [PATCH 1/2] [block]: Make find_image_format() return 'raw' BlockDriver for SG_IO devices

["Nicholas A. Bellinger" <nab@linux-iscsi.org>]

From: Nicholas Bellinger <nab@linux-iscsi.org>

This patch adds a special BlockDriverState->sg check in block.c:find_image_format()
after bdrv_file_open() -> block/raw-posix.c:hdev_open() has been called to determine
if we are dealing with a Linux host scsi-generic device.

The patch then returns the BlockDriver * from bdrv_find_format("raw"), skipping the
subsequent bdrv_read() and rest of find_image_format().

Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>
---
 block.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/block.c b/block.c
index 48305b7..f419ee6 100644
--- a/block.c
+++ b/block.c
@@ -332,6 +332,11 @@ static BlockDriver *find_image_format(const char *filename)
     ret = bdrv_file_open(&bs, filename, 0);
     if (ret < 0)
         return NULL;
+
+    /* Return the raw BlockDriver * to scsi-generic devices */
+    if (bs->sg)
+        return bdrv_find_format("raw");
+
     ret = bdrv_pread(bs, 0, buf, sizeof(buf));
     bdrv_delete(bs);
     if (ret < 0) {
-- 
1.5.6.5