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author | Eric Blake <eblake@redhat.com> | 2018-04-24 14:25:01 -0500 |
---|---|---|
committer | Kevin Wolf <kwolf@redhat.com> | 2018-05-15 16:11:41 +0200 |
commit | e31f6864a6d6fa072a5d02e7679d0db6d0c22311 (patch) | |
tree | fe0b54e73ca4a39f4f49884db18392a9867476dd /block/io.c | |
parent | 7803696d8557e02441a2781a19d4008b2f50925c (diff) | |
download | qemu-e31f6864a6d6fa072a5d02e7679d0db6d0c22311.zip qemu-e31f6864a6d6fa072a5d02e7679d0db6d0c22311.tar.gz qemu-e31f6864a6d6fa072a5d02e7679d0db6d0c22311.tar.bz2 |
block: Support byte-based aio callbacks
We are gradually moving away from sector-based interfaces, towards
byte-based. Add new sector-based aio callbacks for read and write,
to match the fact that bdrv_aio_pdiscard is already byte-based.
Ideally, drivers should be converted to use coroutine callbacks
rather than aio; but that is not quite as trivial (and if we were
to do that conversion, the null-aio driver would disappear), so for
the short term, converting the signature but keeping things with
aio is easier. However, we CAN declare that a driver that uses
the byte-based aio interfaces now defaults to byte-based
operations, and must explicitly provide a refresh_limits override
to stick with larger alignments (making the alignment issues more
obvious directly in the drivers touched in the next few patches).
Once all drivers are converted, the sector-based aio callbacks will
be removed; in the meantime, a FIXME comment is added due to a
slight inefficiency that will be touched up as part of that later
cleanup.
Simplify some instances of 'bs->drv' into 'drv' while touching this,
since the local variable already exists to reduce typing.
Signed-off-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'block/io.c')
-rw-r--r-- | block/io.c | 38 |
1 files changed, 29 insertions, 9 deletions
@@ -92,7 +92,8 @@ void bdrv_refresh_limits(BlockDriverState *bs, Error **errp) } /* Default alignment based on whether driver has byte interface */ - bs->bl.request_alignment = drv->bdrv_co_preadv ? 1 : 512; + bs->bl.request_alignment = (drv->bdrv_co_preadv || + drv->bdrv_aio_preadv) ? 1 : 512; /* Take some limits from the children as a default */ if (bs->file) { @@ -924,12 +925,15 @@ static int coroutine_fn bdrv_driver_preadv(BlockDriverState *bs, return drv->bdrv_co_preadv(bs, offset, bytes, qiov, flags); } + /* FIXME - no need to calculate these if .bdrv_aio_preadv exists */ sector_num = offset >> BDRV_SECTOR_BITS; nb_sectors = bytes >> BDRV_SECTOR_BITS; - assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0); - assert((bytes & (BDRV_SECTOR_SIZE - 1)) == 0); - assert((bytes >> BDRV_SECTOR_BITS) <= BDRV_REQUEST_MAX_SECTORS); + if (!drv->bdrv_aio_preadv) { + assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0); + assert((bytes & (BDRV_SECTOR_SIZE - 1)) == 0); + assert((bytes >> BDRV_SECTOR_BITS) <= BDRV_REQUEST_MAX_SECTORS); + } if (drv->bdrv_co_readv) { return drv->bdrv_co_readv(bs, sector_num, nb_sectors, qiov); @@ -939,8 +943,13 @@ static int coroutine_fn bdrv_driver_preadv(BlockDriverState *bs, .coroutine = qemu_coroutine_self(), }; - acb = bs->drv->bdrv_aio_readv(bs, sector_num, qiov, nb_sectors, + if (drv->bdrv_aio_preadv) { + acb = drv->bdrv_aio_preadv(bs, offset, bytes, qiov, flags, + bdrv_co_io_em_complete, &co); + } else { + acb = drv->bdrv_aio_readv(bs, sector_num, qiov, nb_sectors, bdrv_co_io_em_complete, &co); + } if (acb == NULL) { return -EIO; } else { @@ -972,12 +981,15 @@ static int coroutine_fn bdrv_driver_pwritev(BlockDriverState *bs, goto emulate_flags; } + /* FIXME - no need to calculate these if .bdrv_aio_pwritev exists */ sector_num = offset >> BDRV_SECTOR_BITS; nb_sectors = bytes >> BDRV_SECTOR_BITS; - assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0); - assert((bytes & (BDRV_SECTOR_SIZE - 1)) == 0); - assert((bytes >> BDRV_SECTOR_BITS) <= BDRV_REQUEST_MAX_SECTORS); + if (!drv->bdrv_aio_pwritev) { + assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0); + assert((bytes & (BDRV_SECTOR_SIZE - 1)) == 0); + assert((bytes >> BDRV_SECTOR_BITS) <= BDRV_REQUEST_MAX_SECTORS); + } if (drv->bdrv_co_writev_flags) { ret = drv->bdrv_co_writev_flags(bs, sector_num, nb_sectors, qiov, @@ -992,8 +1004,16 @@ static int coroutine_fn bdrv_driver_pwritev(BlockDriverState *bs, .coroutine = qemu_coroutine_self(), }; - acb = bs->drv->bdrv_aio_writev(bs, sector_num, qiov, nb_sectors, + if (drv->bdrv_aio_pwritev) { + acb = drv->bdrv_aio_pwritev(bs, offset, bytes, qiov, + flags & bs->supported_write_flags, + bdrv_co_io_em_complete, &co); + flags &= ~bs->supported_write_flags; + } else { + assert(!bs->supported_write_flags); + acb = drv->bdrv_aio_writev(bs, sector_num, qiov, nb_sectors, bdrv_co_io_em_complete, &co); + } if (acb == NULL) { ret = -EIO; } else { |