implement qemu_blockalign (Stefano Stabellini)

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

1 files changed, 5 insertions, 0 deletions

diff --git a/block_int.h b/block_int.h
index e10b9069f2..9d119404cf 100644
--- a/block_int.h
+++ b/block_int.h
@@ -145,6 +145,9 @@ struct BlockDriverState {
     /* Whether the disk can expand beyond total_sectors */
     int growable;
 
+    /* the memory alignment required for the buffers handled by this driver */
+    int buffer_alignment;
+
     /* NOTE: the following infos are only hints for real hardware
        drivers. They are not used by the block driver */
     int cyls, heads, secs, translation;
@@ -173,6 +176,8 @@ void *qemu_aio_get_pool(AIOPool *pool, BlockDriverState *bs,
                         BlockDriverCompletionFunc *cb, void *opaque);
 void qemu_aio_release(void *p);
 
+void *qemu_blockalign(BlockDriverState *bs, size_t size);
+
 extern BlockDriverState *bdrv_first;
 
 #endif /* BLOCK_INT_H */