From 6aa46d8ff1ee7e9ca0c4a54d75c74108bee22124 Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Sun, 31 Jan 2016 11:28:57 +0100
Subject: virtio: move VirtQueueElement at the beginning of the structs
The next patch will make virtqueue_pop/vring_pop allocate memory for
the VirtQueueElement. In some cases (blk, scsi, gpu) the device wants
to extend VirtQueueElement with device-specific fields and, until now,
the place of the VirtQueueElement within the containing struct didn't
matter. When allocating the entire block in virtqueue_pop/vring_pop,
however, the containing struct must basically be a "subclass" of
VirtQueueElement, with the VirtQueueElement as the first field. Make
that the case for blk and scsi; gpu is already doing it.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
---
include/hw/virtio/virtio-scsi.h | 13 ++++++-------
1 file changed, 6 insertions(+), 7 deletions(-)
(limited to 'include/hw/virtio/virtio-scsi.h')
diff --git a/include/hw/virtio/virtio-scsi.h b/include/hw/virtio/virtio-scsi.h
index 0394eb23de..eb9d25b9fb 100644
--- a/include/hw/virtio/virtio-scsi.h
+++ b/include/hw/virtio/virtio-scsi.h
@@ -112,18 +112,17 @@ typedef struct VirtIOSCSI {
} VirtIOSCSI;
typedef struct VirtIOSCSIReq {
+ /* Note:
+ * - fields up to resp_iov are initialized by virtio_scsi_init_req;
+ * - fields starting at vring are zeroed by virtio_scsi_init_req.
+ * */
+ VirtQueueElement elem;
+
VirtIOSCSI *dev;
VirtQueue *vq;
QEMUSGList qsgl;
QEMUIOVector resp_iov;
- /* Note:
- * - fields before elem are initialized by virtio_scsi_init_req;
- * - elem is uninitialized at the time of allocation.
- * - fields after elem are zeroed by virtio_scsi_init_req.
- * */
-
- VirtQueueElement elem;
/* Set by dataplane code. */
VirtIOSCSIVring *vring;
--
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