On (22/09/30 15:52), Brian Geffon wrote: > Currently zram will adjust its fops to a version which does not > contain rw_page when a backing device has been assigned. This is > done to prevent upper layers from assuming a synchronous operation > when a page may have been written back. This forces every operation > through bio which has overhead associated with bio_alloc/frees. > > The code can be simplified to always expose a rw_page method and > only in the rare event that a page is written back we instead will > return -EOPNOTSUPP forcing the upper layer to fallback to bio. Reviewed-by: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx> > @@ -1267,6 +1253,9 @@ static int __zram_bvec_read(struct zram *zram, struct page *page, u32 index, > struct bio_vec bvec; > > zram_slot_unlock(zram, index); > + /* If we don't have a bio we came via rw_page, we must fallback to bio */ > + if (!bio) > + return -EOPNOTSUPP; The comment is above 80 cols.
