diff options
| author | Kevin Wolf <kwolf@redhat.com> | 2016-06-03 16:45:44 +0200 |
|---|---|---|
| committer | Kevin Wolf <kwolf@redhat.com> | 2016-06-16 15:19:55 +0200 |
| commit | 23b0d9fb1dd39d85fc2e0cabba5cbe005126e7b5 (patch) | |
| tree | 424f841e03dcfd51cbc20dbad1a43c7e92b376da | |
| parent | 9d52aa3c38484703c05e791bac1ff588588a217c (diff) | |
| download | qemu-23b0d9fb1dd39d85fc2e0cabba5cbe005126e7b5.tar.gz qemu-23b0d9fb1dd39d85fc2e0cabba5cbe005126e7b5.tar.bz2 qemu-23b0d9fb1dd39d85fc2e0cabba5cbe005126e7b5.zip | |
block: Don't enforce 512 byte minimum alignment
If block drivers say that they can do an alignment < 512 bytes, let's
just suppose they mean it. raw-posix used to be an offender with respect
to this, but it can actually deal with byte-aligned requests now.
The default is still 512 bytes for any drivers that only implement
sector-based interfaces, but it is 1 now for drivers that implement
.bdrv_co_preadv.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
| -rw-r--r-- | block.c | 2 | ||||
| -rw-r--r-- | block/io.c | 8 |
2 files changed, 4 insertions, 6 deletions
@@ -937,7 +937,7 @@ static int bdrv_open_common(BlockDriverState *bs, BdrvChild *file, goto fail_opts; } - bs->request_alignment = 512; + bs->request_alignment = drv->bdrv_co_preadv ? 1 : 512; bs->zero_beyond_eof = true; bs->read_only = !(bs->open_flags & BDRV_O_RDWR); diff --git a/block/io.c b/block/io.c index b261cc6327..b3ff9bec38 100644 --- a/block/io.c +++ b/block/io.c @@ -1052,8 +1052,7 @@ int coroutine_fn bdrv_co_preadv(BlockDriverState *bs, BlockDriver *drv = bs->drv; BdrvTrackedRequest req; - /* TODO Lift BDRV_SECTOR_SIZE restriction in BlockDriver interface */ - uint64_t align = MAX(BDRV_SECTOR_SIZE, bs->request_alignment); + uint64_t align = bs->request_alignment; uint8_t *head_buf = NULL; uint8_t *tail_buf = NULL; QEMUIOVector local_qiov; @@ -1305,7 +1304,7 @@ static int coroutine_fn bdrv_co_do_zero_pwritev(BlockDriverState *bs, uint8_t *buf = NULL; QEMUIOVector local_qiov; struct iovec iov; - uint64_t align = MAX(BDRV_SECTOR_SIZE, bs->request_alignment); + uint64_t align = bs->request_alignment; unsigned int head_padding_bytes, tail_padding_bytes; int ret = 0; @@ -1392,8 +1391,7 @@ int coroutine_fn bdrv_co_pwritev(BlockDriverState *bs, BdrvRequestFlags flags) { BdrvTrackedRequest req; - /* TODO Lift BDRV_SECTOR_SIZE restriction in BlockDriver interface */ - uint64_t align = MAX(BDRV_SECTOR_SIZE, bs->request_alignment); + uint64_t align = bs->request_alignment; uint8_t *head_buf = NULL; uint8_t *tail_buf = NULL; QEMUIOVector local_qiov; |