Commit 4841211e authored by Eric Blake's avatar Eric Blake
Browse files

block: Add bdrv_get_request_alignment() 



The next patch needs access to a device's minimum permitted
alignment, since NBD wants to advertise this to clients. Add
an accessor function, borrowing from blk_get_max_transfer()
for accessing a backend's block limits.

Signed-off-by: default avatarEric Blake <eblake@redhat.com>
Reviewed-by: default avatarVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20190329042750.14704-6-eblake@redhat.com>
parent 9cf63850

block/block-backend.c

+7 −0
Original line number Diff line number Diff line
@@ -1764,6 +1764,13 @@ int blk_get_flags(BlockBackend *blk) 
    }

}



/* Returns the minimum request alignment, in bytes; guaranteed nonzero */

uint32_t blk_get_request_alignment(BlockBackend *blk)

{

    BlockDriverState *bs = blk_bs(blk);

    return bs ? bs->bl.request_alignment : BDRV_SECTOR_SIZE;

}



/* Returns the maximum transfer length, in bytes; guaranteed nonzero */

uint32_t blk_get_max_transfer(BlockBackend *blk)

{

include/sysemu/block-backend.h

+1 −0
Original line number Diff line number Diff line
@@ -177,6 +177,7 @@ bool blk_is_available(BlockBackend *blk); 
void blk_lock_medium(BlockBackend *blk, bool locked);

void blk_eject(BlockBackend *blk, bool eject_flag);

int blk_get_flags(BlockBackend *blk);

uint32_t blk_get_request_alignment(BlockBackend *blk);

uint32_t blk_get_max_transfer(BlockBackend *blk);

int blk_get_max_iov(BlockBackend *blk);

void blk_set_guest_block_size(BlockBackend *blk, int align);