Re: [PATCH 11/14] ublk: Fix the lock context annotations

[Bart Van Assche <bvanassche@acm.org>]

On 3/4/26 3:03 PM, Caleb Sander Mateos wrote:
> On Wed, Mar 4, 2026 at 12:55 PM Bart Van Assche <bvanassche@acm.org> wrote:
>> @@ -3581,6 +3584,7 @@ static void ublk_batch_revert_prep_cmd(struct
>> ublk_batch_io_iter *iter,
>>    static int ublk_batch_prep_io(struct ublk_queue *ubq,
>>                                 const struct ublk_batch_io_data *data,
>>                                 const struct ublk_elem_header *elem)
>> +       __must_hold(&data->ub->mutex)
>>    {
>>           struct ublk_io *io = &ubq->ios[elem->tag];
>>           const struct ublk_batch_io *uc = &data->header;
> 
> Sure, these annotations all look correct. But it's not clear to me how
> you're deciding which functions need an annotation. Is clang just
> unable to see that ub->mutex is held here because the function is
> called indirectly through a function pointer?
Clang performs more strict checking of lock context annotations than
sparse. If a function is annotated with __must_hold(), sparse only uses
the information from that annotation while checking the implementation
of that function. Clang not only checks the implementation but also
checks the caller(s).

Thanks,

Bart.