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[Qemu-devel] [6397] Vectored block device API (Avi Kivity)
From: |
Anthony Liguori |
Subject: |
[Qemu-devel] [6397] Vectored block device API (Avi Kivity) |
Date: |
Thu, 22 Jan 2009 16:59:24 +0000 |
Revision: 6397
http://svn.sv.gnu.org/viewvc/?view=rev&root=qemu&revision=6397
Author: aliguori
Date: 2009-01-22 16:59:24 +0000 (Thu, 22 Jan 2009)
Log Message:
-----------
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 <address@hidden>
Signed-off-by: Anthony Liguori <address@hidden>
Modified Paths:
--------------
trunk/block.c
trunk/block.h
Modified: trunk/block.c
===================================================================
--- trunk/block.c 2009-01-22 16:59:20 UTC (rev 6396)
+++ trunk/block.c 2009-01-22 16:59:24 UTC (rev 6397)
@@ -1246,6 +1246,69 @@
/**************************************************************/
/* async I/Os */
+typedef struct VectorTranslationState {
+ QEMUIOVector *iov;
+ uint8_t *bounce;
+ int is_write;
+ BlockDriverAIOCB *aiocb;
+ BlockDriverAIOCB *this_aiocb;
+} VectorTranslationState;
+
+static void bdrv_aio_rw_vector_cb(void *opaque, int ret)
+{
+ VectorTranslationState *s = opaque;
+
+ if (!s->is_write) {
+ qemu_iovec_from_buffer(s->iov, s->bounce);
+ }
+ qemu_free(s->bounce);
+ s->this_aiocb->cb(s->this_aiocb->opaque, ret);
+ qemu_aio_release(s->this_aiocb);
+}
+
+static BlockDriverAIOCB *bdrv_aio_rw_vector(BlockDriverState *bs,
+ int64_t sector_num,
+ QEMUIOVector *iov,
+ int nb_sectors,
+ BlockDriverCompletionFunc *cb,
+ void *opaque,
+ int is_write)
+
+{
+ VectorTranslationState *s = qemu_mallocz(sizeof(*s));
+ BlockDriverAIOCB *aiocb = qemu_aio_get(bs, cb, opaque);
+
+ s->this_aiocb = aiocb;
+ s->iov = iov;
+ s->bounce = qemu_memalign(512, nb_sectors * 512);
+ s->is_write = is_write;
+ if (is_write) {
+ qemu_iovec_to_buffer(s->iov, s->bounce);
+ s->aiocb = bdrv_aio_write(bs, sector_num, s->bounce, nb_sectors,
+ bdrv_aio_rw_vector_cb, s);
+ } else {
+ s->aiocb = bdrv_aio_read(bs, sector_num, s->bounce, nb_sectors,
+ bdrv_aio_rw_vector_cb, s);
+ }
+ return aiocb;
+}
+
+BlockDriverAIOCB *bdrv_aio_readv(BlockDriverState *bs, int64_t sector_num,
+ QEMUIOVector *iov, int nb_sectors,
+ BlockDriverCompletionFunc *cb, void *opaque)
+{
+ return bdrv_aio_rw_vector(bs, sector_num, iov, nb_sectors,
+ cb, opaque, 0);
+}
+
+BlockDriverAIOCB *bdrv_aio_writev(BlockDriverState *bs, int64_t sector_num,
+ QEMUIOVector *iov, int nb_sectors,
+ BlockDriverCompletionFunc *cb, void *opaque)
+{
+ return bdrv_aio_rw_vector(bs, sector_num, iov, nb_sectors,
+ cb, opaque, 1);
+}
+
BlockDriverAIOCB *bdrv_aio_read(BlockDriverState *bs, int64_t sector_num,
uint8_t *buf, int nb_sectors,
BlockDriverCompletionFunc *cb, void *opaque)
@@ -1294,6 +1357,11 @@
{
BlockDriver *drv = acb->bs->drv;
+ if (acb->cb == bdrv_aio_rw_vector_cb) {
+ VectorTranslationState *s = acb->opaque;
+ acb = s->aiocb;
+ }
+
drv->bdrv_aio_cancel(acb);
}
Modified: trunk/block.h
===================================================================
--- trunk/block.h 2009-01-22 16:59:20 UTC (rev 6396)
+++ trunk/block.h 2009-01-22 16:59:24 UTC (rev 6397)
@@ -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 @@
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);
- [Qemu-devel] [6397] Vectored block device API (Avi Kivity),
Anthony Liguori <=