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=-12.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 1D6D4C4363D for ; Wed, 21 Oct 2020 03:21:50 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 2E6BE22253 for ; Wed, 21 Oct 2020 03:21:48 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2E6BE22253 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=h3c.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 0C2EB6B005C; Tue, 20 Oct 2020 23:21:48 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 04A866B0062; Tue, 20 Oct 2020 23:21:47 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E54496B0068; Tue, 20 Oct 2020 23:21:47 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0044.hostedemail.com [216.40.44.44]) by kanga.kvack.org (Postfix) with ESMTP id B4D4D6B005C for ; Tue, 20 Oct 2020 23:21:47 -0400 (EDT) Received: from smtpin09.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 526B4180AD807 for ; Wed, 21 Oct 2020 03:21:47 +0000 (UTC) X-FDA: 77394483054.09.room75_561116227245 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin09.hostedemail.com (Postfix) with ESMTP id 39042180AD802 for ; Wed, 21 Oct 2020 03:21:47 +0000 (UTC) X-HE-Tag: room75_561116227245 X-Filterd-Recvd-Size: 3667 Received: from h3cspam02-ex.h3c.com (smtp.h3c.com [60.191.123.50]) by imf35.hostedemail.com (Postfix) with ESMTP for ; Wed, 21 Oct 2020 03:21:45 +0000 (UTC) Received: from DAG2EX03-BASE.srv.huawei-3com.com ([10.8.0.66]) by h3cspam02-ex.h3c.com with ESMTPS id 09L3LSHn097935 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Wed, 21 Oct 2020 11:21:28 +0800 (GMT-8) (envelope-from tian.xianting@h3c.com) Received: from localhost.localdomain (10.99.212.201) by DAG2EX03-BASE.srv.huawei-3com.com (10.8.0.66) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2106.2; Wed, 21 Oct 2020 11:21:29 +0800 From: Xianting Tian To: CC: , , Xianting Tian Subject: [PATCH] mm: bio_alloc never fails when set GFP_NOIO, GFP_KERNEL Date: Wed, 21 Oct 2020 11:11:28 +0800 Message-ID: <20201021031128.14100-1-tian.xianting@h3c.com> X-Mailer: git-send-email 2.17.1 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.99.212.201] X-ClientProxiedBy: BJSMTP02-EX.srv.huawei-3com.com (10.63.20.133) To DAG2EX03-BASE.srv.huawei-3com.com (10.8.0.66) X-DNSRBL: X-MAIL:h3cspam02-ex.h3c.com 09L3LSHn097935 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: bio_alloc with __GFP_DIRECT_RECLAIM(which is included in GFP_NOIO, GFP_KERNEL) never fails, as stated in the comments of bio_alloc_bioset. So we can remove multiple unneeded null checks of bio_alloc and simplify the code. We have done it in fs/ext4/readpage.c, fs/ext4/page-io.c, fs/direct-io.c, and so forth. Signed-off-by: Xianting Tian --- mm/page_io.c | 31 +++++++++++-------------------- 1 file changed, 11 insertions(+), 20 deletions(-) diff --git a/mm/page_io.c b/mm/page_io.c index e485a6e8a..9215bb356 100644 --- a/mm/page_io.c +++ b/mm/page_io.c @@ -30,18 +30,20 @@ static struct bio *get_swap_bio(gfp_t gfp_flags, struct page *page, bio_end_io_t end_io) { struct bio *bio; + struct block_device *bdev; + /* + * bio_alloc will _always_ be able to allocate a bio if + * __GFP_DIRECT_RECLAIM is set, see comments for bio_alloc_bioset(). + */ bio = bio_alloc(gfp_flags, 1); - if (bio) { - struct block_device *bdev; + bio->bi_iter.bi_sector = map_swap_page(page, &bdev); + bio_set_dev(bio, bdev); + bio->bi_iter.bi_sector <<= PAGE_SHIFT - 9; + bio->bi_end_io = end_io; - bio->bi_iter.bi_sector = map_swap_page(page, &bdev); - bio_set_dev(bio, bdev); - bio->bi_iter.bi_sector <<= PAGE_SHIFT - 9; - bio->bi_end_io = end_io; + bio_add_page(bio, page, thp_size(page), 0); - bio_add_page(bio, page, thp_size(page), 0); - } return bio; } @@ -351,19 +353,13 @@ int __swap_writepage(struct page *page, struct writeback_control *wbc, ret = 0; bio = get_swap_bio(GFP_NOIO, page, end_write_func); - if (bio == NULL) { - set_page_dirty(page); - unlock_page(page); - ret = -ENOMEM; - goto out; - } bio->bi_opf = REQ_OP_WRITE | REQ_SWAP | wbc_to_write_flags(wbc); bio_associate_blkg_from_page(bio, page); count_swpout_vm_event(page); set_page_writeback(page); unlock_page(page); submit_bio(bio); -out: + return ret; } @@ -416,11 +412,6 @@ int swap_readpage(struct page *page, bool synchronous) ret = 0; bio = get_swap_bio(GFP_KERNEL, page, end_swap_bio_read); - if (bio == NULL) { - unlock_page(page); - ret = -ENOMEM; - goto out; - } disk = bio->bi_disk; /* * Keep this task valid during swap readpage because the oom killer may -- 2.17.1