On 1/16/23 10:51 AM, Christoph Hellwig wrote:
> On Mon, Jan 16, 2023 at 09:01:37AM -0700, Jens Axboe wrote:
>> This depends on: 613b14884b85 ("block: handle bio_split_to_limits() NULL return")
>
> Can we sort the NUL vs ERR_PTR thing there first?
Which thing?
>> + /*
>> + * We're doing more than a bio worth of IO (> 256 pages), and we
>> + * cannot guarantee that one of the sub bios will not fail getting
>> + * issued FOR NOWAIT as error results are coalesced across all of
>> + * them. Be safe and ask for a retry of this from blocking context.
>> + */
>> + if (iocb->ki_flags & IOCB_NOWAIT)
>> + return -EAGAIN;
>> return __blkdev_direct_IO(iocb, iter, bio_max_segs(nr_pages));
>
> If the I/O is too a huge page we could easily end up with a single
> bio here.
True - we can push the decision making further down potentially, but
honestly not sure it's worth the effort.
--
Jens Axboe
