scsi-generic: check the return value of bdrv_aio_ioctl in execute_command

This fixes the bug introduced by this commit ad54ae80c73f.
The bdrv_aio_ioctl() still could return null and we should return an error
in that case.

Cc: qemu-stable@nongnu.org
Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/hw/scsi/scsi-generic.c b/hw/scsi/scsi-generic.c
index 19bd36cd541b400b549b2ae701dae2abb29e5f7e..8f195bec00a089d8faf9a08b3abdef65eb03932c 100644 (file)
--- a/hw/scsi/scsi-generic.c
+++ b/hw/scsi/scsi-generic.c
@@ -174,6 +174,9 @@ static int execute_command(BlockDriverState *bdrv,
     r->io_header.flags |= SG_FLAG_DIRECT_IO;
 
     r->req.aiocb = bdrv_aio_ioctl(bdrv, SG_IO, &r->io_header, complete, r);
+    if (r->req.aiocb == NULL) {
+        return -EIO;
+    }
 
     return 0;
 }