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, 3 insertions, 39 deletions

diff --git a/hw/scsi-generic.c b/hw/scsi-generic.c
index 53e8951..f4c615b 100644
--- a/hw/scsi-generic.c
+++ b/hw/scsi-generic.c
@@ -201,8 +201,6 @@ static int execute_command(BlockDriverState *bdrv,
                            SCSIRequest *r, int direction,
 			   BlockDriverCompletionFunc *complete)
 {
-    int ret;
-
     r->io_header.interface_id = 'S';
     r->io_header.dxfer_direction = direction;
     r->io_header.dxferp = r->buf;
@@ -215,27 +213,7 @@ static int execute_command(BlockDriverState *bdrv,
     r->io_header.usr_ptr = r;
     r->io_header.flags |= SG_FLAG_DIRECT_IO;
 
-    ret = bdrv_sg_send_command(bdrv, &r->io_header, sizeof(r->io_header));
-    if (ret < 0) {
-        BADF("execute_command: write failed ! (%d)\n", errno);
-        return -1;
-    }
-    if (complete == NULL) {
-        int ret;
-        r->aiocb = NULL;
-        while ((ret = bdrv_sg_recv_response(bdrv, &r->io_header,
-                                            sizeof(r->io_header))) < 0 &&
-               ret == -EINTR)
-            ;
-        if (ret < 0) {
-            BADF("execute_command: read failed !\n");
-            return -1;
-        }
-        return 0;
-    }
-
-    r->aiocb = bdrv_sg_aio_read(bdrv, (uint8_t*)&r->io_header,
-                                sizeof(r->io_header), complete, r);
+    r->aiocb = bdrv_aio_ioctl(bdrv, SG_IO, &r->io_header, complete, r);
     if (r->aiocb == NULL) {
         BADF("execute_command: read failed !\n");
         return -1;
@@ -637,14 +615,7 @@ static int get_blocksize(BlockDriverState *bdrv)
     io_header.sbp = sensebuf;
     io_header.timeout = 6000; /* XXX */
 
-    ret = bdrv_sg_send_command(bdrv, &io_header, sizeof(io_header));
-    if (ret < 0)
-        return -1;
-
-    while ((ret = bdrv_sg_recv_response(bdrv, &io_header, sizeof(io_header))) < 0 &&
-           ret == -EINTR)
-        ;
-
+    ret = bdrv_ioctl(bdrv, SG_IO, &io_header);
     if (ret < 0)
         return -1;
 
@@ -675,14 +646,7 @@ static int get_stream_blocksize(BlockDriverState *bdrv)
     io_header.sbp = sensebuf;
     io_header.timeout = 6000; /* XXX */
 
-    ret = bdrv_sg_send_command(bdrv, &io_header, sizeof(io_header));
-    if (ret < 0)
-        return -1;
-
-    while ((ret = bdrv_sg_recv_response(bdrv, &io_header, sizeof(io_header))) < 0 &&
-           ret == -EINTR)
-        ;
-
+    ret = bdrv_ioctl(bdrv, SG_IO, &io_header);
     if (ret < 0)
         return -1;