Introduce extended variant of bdrv_co_preadv with qiov_offset parameter, to finally get rid of (most of) local_qiov workarounds.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsement...@virtuozzo.com> --- include/block/block_int.h | 6 +++ block/io.c | 87 ++++++++++++++++++++++++++------------- 2 files changed, 64 insertions(+), 29 deletions(-) diff --git a/include/block/block_int.h b/include/block/block_int.h index 94d45c9708..d66929d5ad 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -211,6 +211,9 @@ struct BlockDriver { */ int coroutine_fn (*bdrv_co_preadv)(BlockDriverState *bs, uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags); + int coroutine_fn (*bdrv_co_preadv_part)(BlockDriverState *bs, + uint64_t offset, uint64_t bytes, + QEMUIOVector *qiov, size_t qiov_offset, int flags); int coroutine_fn (*bdrv_co_writev)(BlockDriverState *bs, int64_t sector_num, int nb_sectors, QEMUIOVector *qiov, int flags); /** @@ -921,6 +924,9 @@ extern BlockDriver bdrv_qcow2; int coroutine_fn bdrv_co_preadv(BdrvChild *child, int64_t offset, unsigned int bytes, QEMUIOVector *qiov, BdrvRequestFlags flags); +int coroutine_fn bdrv_co_preadv_part(BdrvChild *child, + int64_t offset, unsigned int bytes, + QEMUIOVector *qiov, size_t qiov_offset, BdrvRequestFlags flags); int coroutine_fn bdrv_co_pwritev(BdrvChild *child, int64_t offset, unsigned int bytes, QEMUIOVector *qiov, BdrvRequestFlags flags); diff --git a/block/io.c b/block/io.c index 396d5364ba..785a2b07f8 100644 --- a/block/io.c +++ b/block/io.c @@ -979,11 +979,14 @@ static void bdrv_co_io_em_complete(void *opaque, int ret) static int coroutine_fn bdrv_driver_preadv(BlockDriverState *bs, uint64_t offset, uint64_t bytes, - QEMUIOVector *qiov, int flags) + QEMUIOVector *qiov, + size_t qiov_offset, int flags) { BlockDriver *drv = bs->drv; int64_t sector_num; unsigned int nb_sectors; + QEMUIOVector local_qiov; + int ret; assert(!(flags & ~BDRV_REQ_MASK)); assert(!(flags & BDRV_REQ_NO_FALLBACK)); @@ -992,8 +995,20 @@ static int coroutine_fn bdrv_driver_preadv(BlockDriverState *bs, return -ENOMEDIUM; } + if (drv->bdrv_co_preadv_part) { + return drv->bdrv_co_preadv_part(bs, offset, bytes, qiov, qiov_offset, + flags); + } + + if (qiov_offset > 0) { + qemu_iovec_init(&local_qiov, qiov->niov); + qemu_iovec_concat(&local_qiov, qiov, qiov_offset, bytes); + qiov = &local_qiov; + } + if (drv->bdrv_co_preadv) { - return drv->bdrv_co_preadv(bs, offset, bytes, qiov, flags); + ret = drv->bdrv_co_preadv(bs, offset, bytes, qiov, flags); + goto out; } if (drv->bdrv_aio_preadv) { @@ -1005,10 +1020,12 @@ static int coroutine_fn bdrv_driver_preadv(BlockDriverState *bs, acb = drv->bdrv_aio_preadv(bs, offset, bytes, qiov, flags, bdrv_co_io_em_complete, &co); if (acb == NULL) { - return -EIO; + ret = -EIO; + goto out; } else { qemu_coroutine_yield(); - return co.ret; + ret = co.ret; + goto out; } } @@ -1020,7 +1037,14 @@ static int coroutine_fn bdrv_driver_preadv(BlockDriverState *bs, assert((bytes >> BDRV_SECTOR_BITS) <= BDRV_REQUEST_MAX_SECTORS); assert(drv->bdrv_co_readv); - return drv->bdrv_co_readv(bs, sector_num, nb_sectors, qiov); + ret = drv->bdrv_co_readv(bs, sector_num, nb_sectors, qiov); + +out: + if (qiov == &local_qiov) { + qemu_iovec_destroy(&local_qiov); + } + + return ret; } static int coroutine_fn bdrv_driver_pwritev(BlockDriverState *bs, @@ -1103,7 +1127,8 @@ bdrv_driver_pwritev_compressed(BlockDriverState *bs, uint64_t offset, } static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child, - int64_t offset, unsigned int bytes, QEMUIOVector *qiov) + int64_t offset, unsigned int bytes, + QEMUIOVector *qiov, size_t qiov_offset) { BlockDriverState *bs = child->bs; @@ -1183,7 +1208,7 @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child, qemu_iovec_init_buf(&local_qiov, bounce_buffer, pnum); ret = bdrv_driver_preadv(bs, cluster_offset, pnum, - &local_qiov, 0); + &local_qiov, 0, 0); if (ret < 0) { goto err; } @@ -1214,15 +1239,15 @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child, goto err; } - qemu_iovec_from_buf(qiov, progress, bounce_buffer + skip_bytes, + qemu_iovec_from_buf(qiov, qiov_offset + progress, + bounce_buffer + skip_bytes, pnum - skip_bytes); } else { /* Read directly into the destination */ - qemu_iovec_init(&local_qiov, qiov->niov); - qemu_iovec_concat(&local_qiov, qiov, progress, pnum - skip_bytes); - ret = bdrv_driver_preadv(bs, offset + progress, local_qiov.size, - &local_qiov, 0); - qemu_iovec_destroy(&local_qiov); + ret = bdrv_driver_preadv(bs, offset + progress, + MAX(pnum - skip_bytes, + qiov->size - qiov_offset - progress), + qiov, qiov_offset + progress, 0); if (ret < 0) { goto err; } @@ -1247,7 +1272,7 @@ err: */ static int coroutine_fn bdrv_aligned_preadv(BdrvChild *child, BdrvTrackedRequest *req, int64_t offset, unsigned int bytes, - int64_t align, QEMUIOVector *qiov, int flags) + int64_t align, QEMUIOVector *qiov, size_t qiov_offset, int flags) { BlockDriverState *bs = child->bs; int64_t total_bytes, max_bytes; @@ -1258,7 +1283,6 @@ static int coroutine_fn bdrv_aligned_preadv(BdrvChild *child, assert(is_power_of_2(align)); assert((offset & (align - 1)) == 0); assert((bytes & (align - 1)) == 0); - assert(!qiov || bytes == qiov->size); assert((bs->open_flags & BDRV_O_NO_IO) == 0); max_transfer = QEMU_ALIGN_DOWN(MIN_NON_ZERO(bs->bl.max_transfer, INT_MAX), align); @@ -1295,7 +1319,8 @@ static int coroutine_fn bdrv_aligned_preadv(BdrvChild *child, } if (!ret || pnum != bytes) { - ret = bdrv_co_do_copy_on_readv(child, offset, bytes, qiov); + ret = bdrv_co_do_copy_on_readv(child, offset, bytes, + qiov, qiov_offset); goto out; } } @@ -1309,7 +1334,7 @@ static int coroutine_fn bdrv_aligned_preadv(BdrvChild *child, max_bytes = ROUND_UP(MAX(0, total_bytes - offset), align); if (bytes <= max_bytes && bytes <= max_transfer) { - ret = bdrv_driver_preadv(bs, offset, bytes, qiov, 0); + ret = bdrv_driver_preadv(bs, offset, bytes, qiov, qiov_offset, 0); goto out; } @@ -1317,17 +1342,12 @@ static int coroutine_fn bdrv_aligned_preadv(BdrvChild *child, int num; if (max_bytes) { - QEMUIOVector local_qiov; - num = MIN(bytes_remaining, MIN(max_bytes, max_transfer)); assert(num); - qemu_iovec_init(&local_qiov, qiov->niov); - qemu_iovec_concat(&local_qiov, qiov, bytes - bytes_remaining, num); ret = bdrv_driver_preadv(bs, offset + bytes - bytes_remaining, - num, &local_qiov, 0); + num, qiov, bytes - bytes_remaining, 0); max_bytes -= num; - qemu_iovec_destroy(&local_qiov); } else { num = bytes_remaining; ret = qemu_iovec_memset(qiov, bytes - bytes_remaining, 0, @@ -1346,8 +1366,9 @@ out: /* * Handle a read request in coroutine context */ -int coroutine_fn bdrv_co_preadv(BdrvChild *child, - int64_t offset, unsigned int bytes, QEMUIOVector *qiov, +int coroutine_fn bdrv_co_preadv_part(BdrvChild *child, + int64_t offset, unsigned int bytes, + QEMUIOVector *qiov, size_t qiov_offset, BdrvRequestFlags flags) { BlockDriverState *bs = child->bs; @@ -1407,6 +1428,7 @@ int coroutine_fn bdrv_co_preadv(BdrvChild *child, tracked_request_begin(&req, bs, offset, bytes, BDRV_TRACKED_READ); ret = bdrv_aligned_preadv(child, &req, offset, bytes, align, use_local_qiov ? &local_qiov : qiov, + use_local_qiov ? 0 : qiov_offset, flags); tracked_request_end(&req); bdrv_dec_in_flight(bs); @@ -1420,6 +1442,13 @@ int coroutine_fn bdrv_co_preadv(BdrvChild *child, return ret; } +int coroutine_fn bdrv_co_preadv(BdrvChild *child, + int64_t offset, unsigned int bytes, QEMUIOVector *qiov, + BdrvRequestFlags flags) +{ + return bdrv_co_preadv_part(child, offset, bytes, qiov, 0, flags); +} + static int coroutine_fn bdrv_co_do_pwrite_zeroes(BlockDriverState *bs, int64_t offset, int bytes, BdrvRequestFlags flags) { @@ -1734,7 +1763,7 @@ static int coroutine_fn bdrv_co_do_zero_pwritev(BdrvChild *child, wait_serialising_requests(req); bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_HEAD); ret = bdrv_aligned_preadv(child, req, offset & ~(align - 1), align, - align, &local_qiov, 0); + align, &local_qiov, 0, 0); if (ret < 0) { goto fail; } @@ -1772,7 +1801,7 @@ static int coroutine_fn bdrv_co_do_zero_pwritev(BdrvChild *child, wait_serialising_requests(req); bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_TAIL); ret = bdrv_aligned_preadv(child, req, offset, align, - align, &local_qiov, 0); + align, &local_qiov, 0, 0); if (ret < 0) { goto fail; } @@ -1839,7 +1868,7 @@ int coroutine_fn bdrv_co_pwritev(BdrvChild *child, bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_HEAD); ret = bdrv_aligned_preadv(child, &req, offset & ~(align - 1), align, - align, &head_qiov, 0); + align, &head_qiov, 0, 0); if (ret < 0) { goto fail; } @@ -1876,7 +1905,7 @@ int coroutine_fn bdrv_co_pwritev(BdrvChild *child, bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_TAIL); ret = bdrv_aligned_preadv(child, &req, (offset + bytes) & ~(align - 1), - align, align, &tail_qiov, 0); + align, align, &tail_qiov, 0, 0); if (ret < 0) { goto fail; } -- 2.18.0