Allow block driver to map and unmap a buffer for later I/O, as a performance hint.
Signed-off-by: Fam Zheng <[email protected]> --- block/block-backend.c | 10 ++++++++++ block/io.c | 24 ++++++++++++++++++++++++ include/block/block.h | 2 ++ include/block/block_int.h | 4 ++++ include/sysemu/block-backend.h | 3 +++ 5 files changed, 43 insertions(+) diff --git a/block/block-backend.c b/block/block-backend.c index 0df3457..784b936 100644 --- a/block/block-backend.c +++ b/block/block-backend.c @@ -1974,3 +1974,13 @@ static void blk_root_drained_end(BdrvChild *child) } } } + +void blk_dma_map(BlockBackend *blk, void *host, size_t size) +{ + bdrv_dma_map(blk_bs(blk), host, size); +} + +void blk_dma_unmap(BlockBackend *blk, void *host) +{ + bdrv_dma_unmap(blk_bs(blk), host); +} diff --git a/block/io.c b/block/io.c index 2de7c77..988e4db 100644 --- a/block/io.c +++ b/block/io.c @@ -2537,3 +2537,27 @@ void bdrv_io_unplug(BlockDriverState *bs) bdrv_io_unplug(child->bs); } } + +void bdrv_dma_map(BlockDriverState *bs, void *host, size_t size) +{ + BdrvChild *child; + + if (bs->drv && bs->drv->bdrv_dma_map) { + bs->drv->bdrv_dma_map(bs, host, size); + } + QLIST_FOREACH(child, &bs->children, next) { + bdrv_dma_map(child->bs, host, size); + } +} + +void bdrv_dma_unmap(BlockDriverState *bs, void *host) +{ + BdrvChild *child; + + if (bs->drv && bs->drv->bdrv_dma_unmap) { + bs->drv->bdrv_dma_unmap(bs, host); + } + QLIST_FOREACH(child, &bs->children, next) { + bdrv_dma_unmap(child->bs, host); + } +} diff --git a/include/block/block.h b/include/block/block.h index 4c149ad..f59b50a 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -624,4 +624,6 @@ void bdrv_add_child(BlockDriverState *parent, BlockDriverState *child, Error **errp); void bdrv_del_child(BlockDriverState *parent, BdrvChild *child, Error **errp); +void bdrv_dma_map(BlockDriverState *bs, void *host, size_t size); +void bdrv_dma_unmap(BlockDriverState *bs, void *host); #endif diff --git a/include/block/block_int.h b/include/block/block_int.h index 15fa602..4092669 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -381,6 +381,10 @@ struct BlockDriver { uint64_t parent_perm, uint64_t parent_shared, uint64_t *nperm, uint64_t *nshared); + /* Map and unmap a buffer for I/O, as a performance hint to the + * driver. */ + void (*bdrv_dma_map)(BlockDriverState *bs, void *host, size_t size); + void (*bdrv_dma_unmap)(BlockDriverState *bs, void *host); QLIST_ENTRY(BlockDriver) list; }; diff --git a/include/sysemu/block-backend.h b/include/sysemu/block-backend.h index 1e05281..5f7ccdb 100644 --- a/include/sysemu/block-backend.h +++ b/include/sysemu/block-backend.h @@ -239,4 +239,7 @@ void blk_io_limits_disable(BlockBackend *blk); void blk_io_limits_enable(BlockBackend *blk, const char *group); void blk_io_limits_update_group(BlockBackend *blk, const char *group); +void blk_dma_map(BlockBackend *blk, void *host, size_t size); +void blk_dma_unmap(BlockBackend *blk, void *host); + #endif -- 2.9.4
