Commit b461151f authored by Daniel P. Berrangé's avatar Daniel P. Berrangé Committed by Stefan Hajnoczi
Browse files

block: document semantics of bdrv_co_preadv|pwritev 



Reviewed-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: default avatarEric Blake <eblake@redhat.com>
Signed-off-by: default avatarDaniel P. Berrange <berrange@redhat.com>
Message-id: 20170831105456.9558-1-berrange@redhat.com
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
parent 921a3217

include/block/block_int.h

+31 −0
Original line number Diff line number Diff line
@@ -146,12 +146,43 @@ struct BlockDriver { 


    int coroutine_fn (*bdrv_co_readv)(BlockDriverState *bs,

        int64_t sector_num, int nb_sectors, QEMUIOVector *qiov);



    /**

     * @offset: position in bytes to read at

     * @bytes: number of bytes to read

     * @qiov: the buffers to fill with read data

     * @flags: currently unused, always 0

     *

     * @offset and @bytes will be a multiple of 'request_alignment',

     * but the length of individual @qiov elements does not have to

     * be a multiple.

     *

     * @bytes will always equal the total size of @qiov, and will be

     * no larger than 'max_transfer'.

     *

     * The buffer in @qiov may point directly to guest memory.

     */

    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);

    /**

     * @offset: position in bytes to write at

     * @bytes: number of bytes to write

     * @qiov: the buffers containing data to write

     * @flags: zero or more bits allowed by 'supported_write_flags'

     *

     * @offset and @bytes will be a multiple of 'request_alignment',

     * but the length of individual @qiov elements does not have to

     * be a multiple.

     *

     * @bytes will always equal the total size of @qiov, and will be

     * no larger than 'max_transfer'.

     *

     * The buffer in @qiov may point directly to guest memory.

     */

    int coroutine_fn (*bdrv_co_pwritev)(BlockDriverState *bs,

        uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags);