From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_RED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2863FC433DB for ; Sat, 13 Mar 2021 05:08:41 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id C906C64FA7 for ; Sat, 13 Mar 2021 05:08:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C906C64FA7 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 6F66E6B00A1; Sat, 13 Mar 2021 00:08:40 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 6CD336B00A2; Sat, 13 Mar 2021 00:08:40 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5E2EB6B00A3; Sat, 13 Mar 2021 00:08:40 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0169.hostedemail.com [216.40.44.169]) by kanga.kvack.org (Postfix) with ESMTP id 400606B00A1 for ; Sat, 13 Mar 2021 00:08:40 -0500 (EST) Received: from smtpin29.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 0D376181D6075 for ; Sat, 13 Mar 2021 05:08:40 +0000 (UTC) X-FDA: 77913670800.29.F3B4C41 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf22.hostedemail.com (Postfix) with ESMTP id B9FBFC0007C7 for ; Sat, 13 Mar 2021 05:08:36 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id 9765464F9E; Sat, 13 Mar 2021 05:08:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1615612118; bh=TaxE/KGyWhstjGhOfVZASTWuhokBSyHjrCxNHx602qk=; h=Date:From:To:Subject:In-Reply-To:From; b=APXjg6ds2UHPXz0cq0YOo3PDAI8q+M2WHFRSFxoFDfHSl3BxYsZqPUEIJVwzBU2b2 fodT7iDZRClponM9vEBAOS7vsZlKl9mSYJtNV6Dr9li+yI5ML0ij0llTQ7LyKRynlO sks5Yo7hD9LMp0HZRrj1mrOWBkzWd7LME03kPQgk= Date: Fri, 12 Mar 2021 21:08:38 -0800 From: Andrew Morton To: akpm@linux-foundation.org, colin.king@canonical.com, joaodias@google.com, linux-mm@kvack.org, minchan@kernel.org, mm-commits@vger.kernel.org, sergey.senozhatsky@gmail.com, stable@vger.kernel.org, torvalds@linux-foundation.org Subject: [patch 28/29] zram: fix return value on writeback_store Message-ID: <20210313050838.RTs56zfiV%akpm@linux-foundation.org> In-Reply-To: <20210312210632.9b7d62973d72a56fb13c7a03@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Stat-Signature: a8idpufc5h4k6fpewmrw34mi9bo69awn X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: B9FBFC0007C7 Received-SPF: none (linux-foundation.org>: No applicable sender policy available) receiver=imf22; identity=mailfrom; envelope-from=""; helo=mail.kernel.org; client-ip=198.145.29.99 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1615612116-618900 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: From: Minchan Kim Subject: zram: fix return value on writeback_store writeback_store's return value is overwritten by submit_bio_wait's return value. Thus, writeback_store will return zero since there was no IO error. In the end, write syscall from userspace will see the zero as return value, which could make the process stall to keep trying the write until it will succeed. Link: https://lkml.kernel.org/r/20210312173949.2197662-1-minchan@kernel.org Fixes: 3b82a051c101("drivers/block/zram/zram_drv.c: fix error return codes not being returned in writeback_store") Signed-off-by: Minchan Kim Cc: Sergey Senozhatsky Cc: Colin Ian King Cc: John Dias Cc: Signed-off-by: Andrew Morton --- drivers/block/zram/zram_drv.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) --- a/drivers/block/zram/zram_drv.c~zram-fix-return-value-on-writeback_store +++ a/drivers/block/zram/zram_drv.c @@ -627,7 +627,7 @@ static ssize_t writeback_store(struct de struct bio_vec bio_vec; struct page *page; ssize_t ret = len; - int mode; + int mode, err; unsigned long blk_idx = 0; if (sysfs_streq(buf, "idle")) @@ -728,12 +728,17 @@ static ssize_t writeback_store(struct de * XXX: A single page IO would be inefficient for write * but it would be not bad as starter. */ - ret = submit_bio_wait(&bio); - if (ret) { + err = submit_bio_wait(&bio); + if (err) { zram_slot_lock(zram, index); zram_clear_flag(zram, index, ZRAM_UNDER_WB); zram_clear_flag(zram, index, ZRAM_IDLE); zram_slot_unlock(zram, index); + /* + * Return last IO error unless every IO were + * not suceeded. + */ + ret = err; continue; } _