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=-4.0 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_PASS autolearn=unavailable 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 2AEF1C10F00 for ; Thu, 21 Mar 2019 14:22:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E586E218FF for ; Thu, 21 Mar 2019 14:21:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20150623.gappssmtp.com header.i=@kernel-dk.20150623.gappssmtp.com header.b="hxyyP+pS" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728102AbfCUOV7 (ORCPT ); Thu, 21 Mar 2019 10:21:59 -0400 Received: from mail-it1-f196.google.com ([209.85.166.196]:39626 "EHLO mail-it1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728095AbfCUOV7 (ORCPT ); Thu, 21 Mar 2019 10:21:59 -0400 Received: by mail-it1-f196.google.com with SMTP id 139so4314848ita.4 for ; Thu, 21 Mar 2019 07:21:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:from:to:cc:references:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=XgDhbctfX3Arv5rZxySt6y8AH4YckqBWEj3wTbF9LLI=; b=hxyyP+pSce1pi6B/SWx1E/81Qs359gimqlFRDaEwzdgQ7oXeKWeBavUJ9WB6ZN411S WGAA7IBOs9/3fKyS9EVd+AG5zgI/oPl3J6M6b7twKBQn29jZSkpe9cVRsQgOq//nENbk CYyqorm8TKFNJ6tpWHezsiwXs1Tz4i4rkuh1XiWJJCkpsopKn6x3xPuy4aiQHfvBbb0g /xI/n0qhZlTpQUQ41pl8mB0LqnoL3tTZ8fa19UgNaACtlqdFQ7DYECLBoxYsTLgJOst4 I9Tygoq54ANSV6bwL54G1NQ7o/FgUgDjWOvOey8gXaMQ6C7y/G4cMi3Pd2+TYvj3tMIX igLQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:from:to:cc:references:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=XgDhbctfX3Arv5rZxySt6y8AH4YckqBWEj3wTbF9LLI=; b=TAFjDIqOu4dwEkZ/P6QBK6fkZxPMpGI6cCC5nug3kaO+bwGoRZkAUZvbQbYXRSZnBw TYdYEWLq43/LWXp7WtByH8yRpOewwzgEbUssieOYIhFCrvZZub1rwatETxxcm976SpSU X8fM7W69VbGCqpzRSN2+kR8AwU01OCj9wuWdg7BQ5tRat4As3hIW+MUpCkrOyPi+aCzX EfWD99ZisqiEmo9JT0f2Ew0MKth5tN/PLbNYi+RVo9CMhYMwDnmZ12mPPel27YXCafwR jGwqMfz3gIi2FYxci/nO9zep07MwBz4UhazG6GshvgpwSFKiwPqc+Mfd0CormvOLsGVr 8ObQ== X-Gm-Message-State: APjAAAVeGM5CMmP2PfAUPcMVzq+LJ7WNAJ3GMNfLvWhlF5DapBMpYzHZ mqZN4fnHr5McGy6yiL8TK1OdXhER0httPg== X-Google-Smtp-Source: APXvYqwnYLYSPIIkfnqlzWgi79+mGsKpLokjfu0tFyX837vTrSmx4RZNsFgYnk22snHG6i7s85N+WA== X-Received: by 2002:a05:660c:a18:: with SMTP id e24mr2783545itk.129.1553178117386; Thu, 21 Mar 2019 07:21:57 -0700 (PDT) Received: from [192.168.1.158] ([216.160.245.98]) by smtp.gmail.com with ESMTPSA id n4sm347424ioh.52.2019.03.21.07.21.55 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 21 Mar 2019 07:21:56 -0700 (PDT) Subject: Re: [PATCH 1/2] block: bio: ensure newly added bio flags don't override BVEC_POOL_IDX From: Jens Axboe To: Johannes Thumshirn Cc: Hannes Reinecke , Bart Van Assche , Christoph Hellwig , Jan Kara , Linux Block Layer Mailinglist , Linux FSDEVEL Mailinglist References: <20190321123045.32396-1-jthumshirn@suse.de> <20190321123045.32396-2-jthumshirn@suse.de> <78cf685f-2bb4-c494-4677-afa513b47339@fb.com> Message-ID: <17f1ef65-5fcf-0cba-4d37-a43d5e5038b0@kernel.dk> Date: Thu, 21 Mar 2019 08:21:55 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.1 MIME-Version: 1.0 In-Reply-To: <78cf685f-2bb4-c494-4677-afa513b47339@fb.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On 3/21/19 8:15 AM, Jens Axboe wrote: > You also haven't solved the issue of now having an extra bit, 2/2 uses > the last bit which the other patch already took... Here's one way - kill BIO_SEG_VALID. We should just use ->bi_phys_segments to tell if it's valid or not. This patch uses -1 to signify it's not. Totally untested... diff --git a/block/bio.c b/block/bio.c index 71a78d9fb8b7..4bc165e7ca43 100644 --- a/block/bio.c +++ b/block/bio.c @@ -280,6 +280,7 @@ void bio_init(struct bio *bio, struct bio_vec *table, unsigned short max_vecs) { memset(bio, 0, sizeof(*bio)); + bio->bi_phys_segments = -1; atomic_set(&bio->__bi_remaining, 1); atomic_set(&bio->__bi_cnt, 1); @@ -305,6 +306,7 @@ void bio_reset(struct bio *bio) bio_uninit(bio); memset(bio, 0, BIO_RESET_BYTES); + bio->bi_phys_segments = -1; bio->bi_flags = flags; atomic_set(&bio->__bi_remaining, 1); } @@ -573,7 +575,7 @@ EXPORT_SYMBOL(bio_put); int bio_phys_segments(struct request_queue *q, struct bio *bio) { - if (unlikely(!bio_flagged(bio, BIO_SEG_VALID))) + if (unlikely(bio->bi_phys_segments == -1)) blk_recount_segments(q, bio); return bio->bi_phys_segments; @@ -731,7 +733,7 @@ int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page /* If we may be able to merge these biovecs, force a recount */ if (bio->bi_vcnt > 1 && biovec_phys_mergeable(q, bvec - 1, bvec)) - bio_clear_flag(bio, BIO_SEG_VALID); + bio->bi_phys_segments = -1; done: return len; @@ -1913,10 +1915,8 @@ void bio_trim(struct bio *bio, int offset, int size) if (offset == 0 && size == bio->bi_iter.bi_size) return; - bio_clear_flag(bio, BIO_SEG_VALID); - + bio->bi_phys_segments = -1; bio_advance(bio, offset << 9); - bio->bi_iter.bi_size = size; if (bio_integrity(bio)) diff --git a/block/blk-merge.c b/block/blk-merge.c index 1c9d4f0f96ea..57cea2782a76 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -343,7 +343,6 @@ void blk_queue_split(struct request_queue *q, struct bio **bio) /* physical segments can be figured out during splitting */ res = split ? split : *bio; res->bi_phys_segments = nsegs; - bio_set_flag(res, BIO_SEG_VALID); if (split) { /* there isn't chance to merge the splitted bio */ @@ -440,8 +439,6 @@ void blk_recount_segments(struct request_queue *q, struct bio *bio) bio->bi_next = NULL; bio->bi_phys_segments = __blk_recalc_rq_segments(q, bio); bio->bi_next = nxt; - - bio_set_flag(bio, BIO_SEG_VALID); } static int blk_phys_contig_segment(struct request_queue *q, struct bio *bio, @@ -651,9 +648,9 @@ int ll_back_merge_fn(struct request_queue *q, struct request *req, req_set_nomerge(q, req); return 0; } - if (!bio_flagged(req->biotail, BIO_SEG_VALID)) + if (req->biotail->bi_phys_segments == -1) blk_recount_segments(q, req->biotail); - if (!bio_flagged(bio, BIO_SEG_VALID)) + if (bio->bi_phys_segments == -1) blk_recount_segments(q, bio); return ll_new_hw_segment(q, req, bio); @@ -673,9 +670,9 @@ int ll_front_merge_fn(struct request_queue *q, struct request *req, req_set_nomerge(q, req); return 0; } - if (!bio_flagged(bio, BIO_SEG_VALID)) + if (bio->bi_phys_segments == -1) blk_recount_segments(q, bio); - if (!bio_flagged(req->bio, BIO_SEG_VALID)) + if (req->bio->bi_phys_segments == -1) blk_recount_segments(q, req->bio); return ll_new_hw_segment(q, req, bio); diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index c033bfcb209e..79eb54dcf0f9 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -5247,7 +5247,7 @@ static int raid5_read_one_chunk(struct mddev *mddev, struct bio *raid_bio) rcu_read_unlock(); raid_bio->bi_next = (void*)rdev; bio_set_dev(align_bi, rdev->bdev); - bio_clear_flag(align_bi, BIO_SEG_VALID); + align_bi->bi_phys_segments = -1; if (is_badblock(rdev, align_bi->bi_iter.bi_sector, bio_sectors(align_bi), diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h index d66bf5f32610..472059e92071 100644 --- a/include/linux/blk_types.h +++ b/include/linux/blk_types.h @@ -215,7 +215,6 @@ struct bio { /* * bio flags */ -#define BIO_SEG_VALID 1 /* bi_phys_segments valid */ #define BIO_CLONED 2 /* doesn't own data */ #define BIO_BOUNCED 3 /* bio is a bounce bio */ #define BIO_USER_MAPPED 4 /* contains user pages */ -- Jens Axboe