Re: [PATCH v2 07/26] block: add missing coroutine_fn annotations

[Paolo Bonzini]

On 5/13/22 23:26, Eric Blake wrote:
> > +int coroutine_fn blk_pwrite_zeroes(BlockBackend *blk, int64_t offset,
> > +                                   int64_t bytes, BdrvRequestFlags flags)
> Tracking down all callers of blk_pwrite_zeroes is not as trivial as in
> the previous patches.  But the very first one I checked:
>   block.c: create_file_fallback_zero_first_sector()
>
> is neither marked coroutine_fn, nor does it have the "if
> (qemu_in_coroutine())" guard.

That one in particular _should_ be coroutine_fn; 
bdrv_co_create_opts_simple is the only caller.  This is probably a 
limitation of the thread-safety annotations that I used to generate this 
patchset: the compiler does limited inter-procedural analysis which for 
us means missing some potential coroutine_fn additions.

But I agree that blk_pwrite_zeros shouldn't be a coroutine_fn, because 
of fuse_fallocate and block_load.  Alberto, this function is another 
candidate for adding a blk_co_pwrite_zeros + a matching 
generated_co_wrapper.

Paolo

>  And block.c is not touched in this
> patch series, per the diffstat in 0/26.  Am I missing something?