On Mon, Jul 01, 2019 at 12:16:44PM +0800, Ming Lei wrote: > 'bio->bi_iter.bi_size' is 'unsigned int', which at most hold 4G - 1 > bytes. > > Before 07173c3ec276 ("block: enable multipage bvecs"), one bio can > include very limited pages, and usually at most 256, so the fs bio > size won't be bigger than 1M bytes most of times. > > Since we support multi-page bvec, in theory one fs bio really can > be added > 1M pages, especially in case of hugepage, or big writeback > in case of huge dirty pages. Then there is chance in which .bi_size > is overflowed. > > Fixes this issue by adding bio_will_full() which checks if the added > segment may overflow .bi_size. Can you please just add the argument to bio_full? bio_will_full sounds rather odd. Maybe also add a kerneldoc comment to the new bio_full to explain it. Otherwise this looks fine to me.