Re: block: fail unaligned bio from submit_bio_noacct()

[Mikulas Patocka <mpatocka@redhat.com>]

On Fri, 22 Mar 2024, Ming Lei wrote:

> On Thu, Mar 21, 2024 at 06:01:41PM +0100, Mikulas Patocka wrote:
> > 
> > 
> > > > +static bool bio_check_alignment(struct bio *bio, struct request_queue *q)
> > > > +{
> > > > +	unsigned int bs = q->limits.logical_block_size;
> > > > +	unsigned int size = bio->bi_iter.bi_size;
> > > > +
> > > > +	if (size & (bs - 1))
> > > > +		return false;
> > > > +
> > > > +	if (size && ((bio->bi_iter.bi_sector << SECTOR_SHIFT) & (bs - 1)))
> > > > +		return false;
> > > > +
> > > > +	return true;
> > > > +}
> > 
> > I would change it to
> > 
> > if (unlikely(((bi_iter.bi_sector | bio_sectors(bio)) & ((queue_logical_block_size(q) >> 9) - 1)) != 0))
> > 	return false;
> 
> What if bio->bi_iter.bi_size isn't aligned with 512? The above check
> can't find that at all.

Could it happen that bi_size is not aligned to 512? I haven't seen such a 
bio yet. If you have seen it, say where was it created.

Mikulas