Am 04.11.2022 um 09:44 hat Paolo Bonzini geschrieben: > On 11/4/22 08:35, Emanuele Giuseppe Esposito wrote: > > But isn't it a bug also not to mark a function _only_ called by > > coroutine_fn? My point is that if this function is an implementation of > > a BlockDriver callback marked as coroutine_fn (like in patch 6 with > > vmdk), then it would make sense. > > If a function implements a coroutine_fn callback but does not suspend, then > it makes sense to mark it coroutine_fn. > > In general it's not a bug. In most cases it would only be a coincidence > that the function is called from a coroutine_fn. For example consider > bdrv_round_to_clusters(). Marking it coroutine_fn signals that it may > suspend now (it doesn't) or in the future. However it's only doing some > math based on the result of bdrv_get_info(), so it is extremely unlikely > that this will happen. > > In this case... oh wait. block_copy_is_cluster_allocated is calling > bdrv_is_allocated, and block_copy_reset_unallocated calls > block_copy_is_cluster_allocated. bdrv_is_allocated is a mixed > coroutine/non-coroutine function, and in this case it is useful to document > that bdrv_is_allocated will suspend. The patch is correct, only the commit > message is wrong.
Ah, right, now I remember that this is what I had discussed with Emanuele. I knew that there was a reason for it... What we probably should really do is a bdrv_co_is_allocated() that doesn't go through the mixed function, but directly calls bdrv_co_common_block_status_above(). bdrv_is_allocated() is only a smaller wrapper anyway, so it wouldn't duplicate much code. I seem to remember that Emanuele had a few more bdrv_is_allocated() calls that actually took the coroutine path and could use the same new function. Kevin
