block: Add blk_by_dev()

This finds a BlockBackend given the device model that is attached to it.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
This commit is contained in:
Kevin Wolf 2016-09-20 13:38:40 +02:00
parent 6bed028056
commit 1c89e1fa2f
2 changed files with 20 additions and 0 deletions

View File

@ -559,6 +559,25 @@ void *blk_get_attached_dev(BlockBackend *blk)
return blk->dev; return blk->dev;
} }
/*
* Return the BlockBackend which has the device model @dev attached if it
* exists, else null.
*
* @dev must not be null.
*/
BlockBackend *blk_by_dev(void *dev)
{
BlockBackend *blk = NULL;
assert(dev != NULL);
while ((blk = blk_all_next(blk)) != NULL) {
if (blk->dev == dev) {
return blk;
}
}
return NULL;
}
/* /*
* Set @blk's device model callbacks to @ops. * Set @blk's device model callbacks to @ops.
* @opaque is the opaque argument to pass to the callbacks. * @opaque is the opaque argument to pass to the callbacks.

View File

@ -111,6 +111,7 @@ int blk_attach_dev(BlockBackend *blk, void *dev);
void blk_attach_dev_nofail(BlockBackend *blk, void *dev); void blk_attach_dev_nofail(BlockBackend *blk, void *dev);
void blk_detach_dev(BlockBackend *blk, void *dev); void blk_detach_dev(BlockBackend *blk, void *dev);
void *blk_get_attached_dev(BlockBackend *blk); void *blk_get_attached_dev(BlockBackend *blk);
BlockBackend *blk_by_dev(void *dev);
void blk_set_dev_ops(BlockBackend *blk, const BlockDevOps *ops, void *opaque); void blk_set_dev_ops(BlockBackend *blk, const BlockDevOps *ops, void *opaque);
int blk_pread_unthrottled(BlockBackend *blk, int64_t offset, uint8_t *buf, int blk_pread_unthrottled(BlockBackend *blk, int64_t offset, uint8_t *buf,
int count); int count);