On Wed, Aug 18, 2021 at 03:37:38PM +0800, Guoqing Jiang wrote:
> for (i = 0; i < disks; i++) {
> struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
> +
> + if (test_bit(WriteMostly, &mirror->rdev->flags))
> + write_behind = true;
How does this condition relate to the ones used for actually calling
alloc_behind_master_bio? It looks related, but as someone not familiar
with the code I can't really verify if this is correct, so a comment
explaining it might be useful.
> + /*
> + * When using a bitmap, we may call alloc_behind_master_bio below.
> + * alloc_behind_master_bio allocates a copy of the data payload a page
> + * at a time and thus needs a new bio that can fit the whole payload
> + * this bio in page sized chunks.
> + */
> + if (write_behind && bitmap)
> + max_sectors = min_t(int, max_sectors, BIO_MAX_VECS * PAGE_SECTORS);
Overly long line here.
