Vectored block device API (Avi Kivity)

Most devices that are capable of DMA are also capable of scatter-gather.
With the memory mapping API, this means that the device code needs to be
able to access discontiguous host memory regions.

For block devices, this translates to vectored I/O.  This patch implements
an aynchronous vectored interface for the qemu block devices.  At the moment
all I/O is bounced and submitted through the non-vectored API; in the future
we will convert block devices to natively support vectored I/O wherever
possible.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6397 c046a42c-6fe2-441c-8c8c-71466251a162

1 files changed, 8 insertions, 0 deletions

diff --git a/block.h b/block.h
index c3314a1dbe..9733409018 100644
--- a/block.h
+++ b/block.h
@@ -2,6 +2,7 @@
 #define BLOCK_H
 
 #include "qemu-aio.h"
+#include "qemu-common.h"
 
 /* block.c */
 typedef struct BlockDriver BlockDriver;
@@ -85,6 +86,13 @@ int bdrv_commit(BlockDriverState *bs);
 typedef struct BlockDriverAIOCB BlockDriverAIOCB;
 typedef void BlockDriverCompletionFunc(void *opaque, int ret);
 
+BlockDriverAIOCB *bdrv_aio_readv(BlockDriverState *bs, int64_t sector_num,
+                                 QEMUIOVector *iov, int nb_sectors,
+                                 BlockDriverCompletionFunc *cb, void *opaque);
+BlockDriverAIOCB *bdrv_aio_writev(BlockDriverState *bs, int64_t sector_num,
+                                  QEMUIOVector *iov, int nb_sectors,
+                                  BlockDriverCompletionFunc *cb, void *opaque);
+
 BlockDriverAIOCB *bdrv_aio_read(BlockDriverState *bs, int64_t sector_num,
                                 uint8_t *buf, int nb_sectors,
                                 BlockDriverCompletionFunc *cb, void *opaque);