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| author | Stefan Hajnoczi | 2022-10-13 20:58:59 +0200 |
|---|---|---|
| committer | Stefan Hajnoczi | 2022-10-26 20:56:42 +0200 |
| commit | 4f384011c5a37f80dc6cadefffac61ffb1c3aa1e (patch) | |
| tree | d720ec42488e83afa07d95c45ee33c3f0a15d6fa /include/block | |
| parent | numa: call ->ram_block_removed() in ram_block_notifer_remove() (diff) | |
| download | qemu-4f384011c5a37f80dc6cadefffac61ffb1c3aa1e.tar.gz qemu-4f384011c5a37f80dc6cadefffac61ffb1c3aa1e.tar.xz qemu-4f384011c5a37f80dc6cadefffac61ffb1c3aa1e.zip | |
block: pass size to bdrv_unregister_buf()
The only implementor of bdrv_register_buf() is block/nvme.c, where the
size is not needed when unregistering a buffer. This is because
util/vfio-helpers.c can look up mappings by address.
Future block drivers that implement bdrv_register_buf() may not be able
to do their job given only the buffer address. Add a size argument to
bdrv_unregister_buf().
Also document the assumptions about
bdrv_register_buf()/bdrv_unregister_buf() calls. The same <host, size>
values that were given to bdrv_register_buf() must be given to
bdrv_unregister_buf().
gcc 11.2.1 emits a spurious warning that img_bench()'s buf_size local
variable might be uninitialized, so it's necessary to silence the
compiler.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Message-id: 20221013185908.1297568-5-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'include/block')
| -rw-r--r-- | include/block/block-global-state.h | 5 | ||||
| -rw-r--r-- | include/block/block_int-common.h | 2 |
2 files changed, 5 insertions, 2 deletions
diff --git a/include/block/block-global-state.h b/include/block/block-global-state.h index 21265e3966..7901f35863 100644 --- a/include/block/block-global-state.h +++ b/include/block/block-global-state.h @@ -243,9 +243,12 @@ void bdrv_del_child(BlockDriverState *parent, BdrvChild *child, Error **errp); * Register/unregister a buffer for I/O. For example, VFIO drivers are * interested to know the memory areas that would later be used for I/O, so * that they can prepare IOMMU mapping etc., to get better performance. + * + * Buffers must not overlap and they must be unregistered with the same <host, + * size> values that they were registered with. */ void bdrv_register_buf(BlockDriverState *bs, void *host, size_t size); -void bdrv_unregister_buf(BlockDriverState *bs, void *host); +void bdrv_unregister_buf(BlockDriverState *bs, void *host, size_t size); void bdrv_cancel_in_flight(BlockDriverState *bs); diff --git a/include/block/block_int-common.h b/include/block/block_int-common.h index 8947abab76..b7a7cbd3a5 100644 --- a/include/block/block_int-common.h +++ b/include/block/block_int-common.h @@ -435,7 +435,7 @@ struct BlockDriver { * DMA mapping for hot buffers. */ void (*bdrv_register_buf)(BlockDriverState *bs, void *host, size_t size); - void (*bdrv_unregister_buf)(BlockDriverState *bs, void *host); + void (*bdrv_unregister_buf)(BlockDriverState *bs, void *host, size_t size); /* * This field is modified only under the BQL, and is part of |