From 3fb06697ae30ea59bf245f967a043e60f2aedb17 Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Mon, 25 Apr 2016 11:25:18 +0200 Subject: [PATCH] block: Introduce .bdrv_co_preadv/pwritev BlockDriver function Many parts of the block layer are already byte granularity. The block driver interface, however, was still missing an interface that allows making use of this. This patch introduces a new BlockDriver interface, which is based on coroutines, vectored, has flags and uses a byte granularity. This is now the preferred interface for new drivers. Signed-off-by: Kevin Wolf Reviewed-by: Eric Blake Reviewed-by: Fam Zheng --- block/io.c | 28 ++++++++++++++++++++++------ include/block/block_int.h | 4 ++++ 2 files changed, 26 insertions(+), 6 deletions(-) diff --git a/block/io.c b/block/io.c index feddb71..70caadd 100644 --- a/block/io.c +++ b/block/io.c @@ -803,8 +803,15 @@ static int coroutine_fn bdrv_driver_preadv(BlockDriverState *bs, QEMUIOVector *qiov, int flags) { BlockDriver *drv = bs->drv; - int64_t sector_num = offset >> BDRV_SECTOR_BITS; - unsigned int nb_sectors = bytes >> BDRV_SECTOR_BITS; + int64_t sector_num; + unsigned int nb_sectors; + + if (drv->bdrv_co_preadv) { + return drv->bdrv_co_preadv(bs, offset, bytes, qiov, flags); + } + + 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); @@ -834,10 +841,18 @@ static int coroutine_fn bdrv_driver_pwritev(BlockDriverState *bs, QEMUIOVector *qiov, int flags) { BlockDriver *drv = bs->drv; - int64_t sector_num = offset >> BDRV_SECTOR_BITS; - unsigned int nb_sectors = bytes >> BDRV_SECTOR_BITS; + int64_t sector_num; + unsigned int nb_sectors; int ret; + if (drv->bdrv_co_pwritev) { + ret = drv->bdrv_co_pwritev(bs, offset, bytes, qiov, flags); + goto emulate_flags; + } + + 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); @@ -857,13 +872,14 @@ static int coroutine_fn bdrv_driver_pwritev(BlockDriverState *bs, acb = bs->drv->bdrv_aio_writev(bs, sector_num, qiov, nb_sectors, bdrv_co_io_em_complete, &co); if (acb == NULL) { - return -EIO; + ret = -EIO; } else { qemu_coroutine_yield(); - return co.ret; + ret = co.ret; } } +emulate_flags: if (ret == 0 && (flags & BDRV_REQ_FUA) && !(drv->supported_write_flags & BDRV_REQ_FUA)) { diff --git a/include/block/block_int.h b/include/block/block_int.h index 804bc1d..565f795 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -153,10 +153,14 @@ struct BlockDriver { int coroutine_fn (*bdrv_co_readv)(BlockDriverState *bs, int64_t sector_num, int nb_sectors, QEMUIOVector *qiov); + int coroutine_fn (*bdrv_co_preadv)(BlockDriverState *bs, + uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags); int coroutine_fn (*bdrv_co_writev)(BlockDriverState *bs, int64_t sector_num, int nb_sectors, QEMUIOVector *qiov); int coroutine_fn (*bdrv_co_writev_flags)(BlockDriverState *bs, int64_t sector_num, int nb_sectors, QEMUIOVector *qiov, int flags); + int coroutine_fn (*bdrv_co_pwritev)(BlockDriverState *bs, + uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags); int supported_write_flags; -- 2.7.4