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implement qemu_blockalign (Stefano Stabellini)

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this patch adds a buffer_alignment field to BlockDriverState and
implements a qemu_blockalign function that uses that field to allocate a
memory aligned buffer to be used by the block driver.
buffer_alignment is initialized to 512 but each block driver can set
a different value (at the moment none of them do).
This patch modifies ide.c, block-qcow.c, block-qcow2.c and block.c to
use qemu_blockalign instead of qemu_memalign.
There is only one place left that still uses qemu_memalign to allocate
buffers used by block drivers that is posix-aio-compat:handle_aiocb_rw
because it is not possible to get the BlockDriverState from that
function. However I think it is not important because posix-aio-compat
already deals with driver specific code so it is supposed to know its
own needs.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@7229 c046a42c-6fe2-441c-8c8c-71466251a162
This commit is contained in:
aliguori 2009-04-22 20:20:00 +00:00
parent 94909d9fd9
commit e268ca5232
6 changed files with 18 additions and 6 deletions
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9
block.c
View file

@ -362,6 +362,8 @@ int bdrv_open2(BlockDriverState *bs, const char *filename, int flags,
bs->is_temporary = 0;
bs->encrypted = 0;
bs->valid_key = 0;
/* buffer_alignment defaulted to 512, drivers can change this value */
bs->buffer_alignment = 512;
if (flags & BDRV_O_SNAPSHOT) {
BlockDriverState *bs1;
@ -1390,7 +1392,7 @@ static BlockDriverAIOCB *bdrv_aio_rw_vector(BlockDriverState *bs,
acb = qemu_aio_get(bs, cb, opaque);
acb->is_write = is_write;
acb->qiov = qiov;
acb->bounce = qemu_memalign(512, qiov->size);
acb->bounce = qemu_blockalign(bs, qiov->size);
if (!acb->bh)
acb->bh = qemu_bh_new(bdrv_aio_bh_cb, acb);
@ -1640,3 +1642,8 @@ BlockDriverAIOCB *bdrv_aio_ioctl(BlockDriverState *bs,
return drv->bdrv_aio_ioctl(bs, req, buf, cb, opaque);
return NULL;
}
void *qemu_blockalign(BlockDriverState *bs, size_t size)
{
return qemu_memalign((bs && bs->buffer_alignment) ? bs->buffer_alignment : 512, size);
}