On Thu, Mar 21, 2024 at 08:14:24AM -0700, Bart Van Assche wrote:
> On 3/21/24 06:16, Ming Lei 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;
> Why "size &&"? It doesn't harm to reject unaligned bios if size == 0 and
> it will reduce the number of if-tests in the hot path.
It doesn't make sense to check the alignment for bio without data.
>
> Why to shift bio->bi_iter.bi_sector left instead of shifting (bs - 1)
> right?
unit of bs is bytes, so .bi_sector needs to be converted to byte first.
Thanks,
Ming
