new scsi-generic abstraction, use SG_IO (Christoph Hellwig)

Okay, I started looking into how to handle scsi-generic I/O in the
new world order.

I think the best is to use the SG_IO ioctl instead of the read/write
interface as that allows us to support scsi passthrough on disk/cdrom
devices, too.  See Hannes patch on the kvm list from August for an
example.

Now that we always do ioctls we don't need another abstraction than
bdrv_ioctl for the synchronous requests for now, and for asynchronous
requests I've added a aio_ioctl abstraction keeping it simple.

Long-term we might want to move the ops to a higher-level abstraction
and let the low-level code fill out the request header, but I'm lazy
enough to leave that to the people trying to support scsi-passthrough
on a non-Linux OS.

Tested lightly by issuing various sg_ commands from sg3-utils in a guest
to a host CDROM device.


Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6895 c046a42c-6fe2-441c-8c8c-71466251a162

1 files changed, 7 insertions, 18 deletions

diff --git a/block.c b/block.c
index 6479072..7230f04 100644
--- a/block.c
+++ b/block.c
@@ -1633,24 +1633,13 @@ int bdrv_ioctl(BlockDriverState *bs, unsigned long int req, void *buf)
     return -ENOTSUP;
 }
 
-int bdrv_sg_send_command(BlockDriverState *bs, void *buf, int count)
-{
-    return bs->drv->bdrv_sg_send_command(bs, buf, count);
-}
-
-int bdrv_sg_recv_response(BlockDriverState *bs, void *buf, int count)
-{
-    return bs->drv->bdrv_sg_recv_response(bs, buf, count);
-}
-
-BlockDriverAIOCB *bdrv_sg_aio_read(BlockDriverState *bs, void *buf, int count,
-                                   BlockDriverCompletionFunc *cb, void *opaque)
+BlockDriverAIOCB *bdrv_aio_ioctl(BlockDriverState *bs,
+        unsigned long int req, void *buf,
+        BlockDriverCompletionFunc *cb, void *opaque)
 {
-    return bs->drv->bdrv_sg_aio_read(bs, buf, count, cb, opaque);
-}
+    BlockDriver *drv = bs->drv;
 
-BlockDriverAIOCB *bdrv_sg_aio_write(BlockDriverState *bs, void *buf, int count,
-                                    BlockDriverCompletionFunc *cb, void *opaque)
-{
-    return bs->drv->bdrv_sg_aio_write(bs, buf, count, cb, opaque);
+    if (drv && drv->bdrv_aio_ioctl)
+        return drv->bdrv_aio_ioctl(bs, req, buf, cb, opaque);
+    return NULL;
 }