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dkim=pass header.d=google.com header.s=20210112 header.b=XKGhDGNI; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf15.hostedemail.com: domain of bgeffon@google.com designates 209.85.128.176 as permitted sender) smtp.mailfrom=bgeffon@google.com X-Stat-Signature: 5mh94jr347ksj9riwmajqzw5as48dxkw X-Rspamd-Queue-Id: E44F7A0018 X-Rspamd-Server: rspam09 X-HE-Tag: 1664808488-568777 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Sun, Oct 2, 2022 at 10:59 PM Sergey Senozhatsky wrote: > > 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 Thank you. > > > @@ -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. Fixed in a new patch.