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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 90DD6C001E0 for ; Mon, 31 Jul 2023 17:15:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233903AbjGaRP4 (ORCPT ); Mon, 31 Jul 2023 13:15:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41346 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232855AbjGaRPR (ORCPT ); Mon, 31 Jul 2023 13:15:17 -0400 Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EB127BD for ; Mon, 31 Jul 2023 10:12:51 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id 3f1490d57ef6-c5fc972760eso5244527276.1 for ; Mon, 31 Jul 2023 10:12:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1690823571; x=1691428371; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=nlUlu5Mhd5cq+/dnIWytp1wDOwye9pYqWME5wT1VG2E=; b=sHGO4YkHIV7FKB9rSFdsUdceu+sd5n7SB4rQ2unW3pD+BVqkwNJbz+SITG2pysaMgl gKtSzBeA+OBMePojGafJ+11doCnzqSxZKPCriFEkRtJWp27lsz7elqgKl6T8eOE/f8yK w7zw6fW868PqBeRY5qLJOdGEIjLR+7606TSSgtlwLhhrV02LXp2unR5jYo2ZCHxqOD6/ aTLQZWV2NWG8NNR6Zbwdm5er8wOMF1YxeMP3rfPV2nuC2GAZIApB/MNhrk0KohkTdxbo aZdUz3A18SoWVWors7K7+klRf0vOn2JYaGIHOGPalUyPxopNDj0TFe/WRuIA3D+NB8/C cl3g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690823571; x=1691428371; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=nlUlu5Mhd5cq+/dnIWytp1wDOwye9pYqWME5wT1VG2E=; b=Usjq+mLQ18JK9kAVMn3M4OCCBJyn46dxIA2XwO3wSTrxSU6V86j7ATBFF8kQSGhiHk ZmAQCZ3TGH5lXpphjU0Bcbl2+M36DIXLsvvSyQE2NaxPiNb6WuC7yPEtnX5e7vv2VzQe ztYt0va8PlzOeD/d2Go9s6qGBMW4TZSviixsRv5u9qTgdwI2sydVqSKwGJLOvI8ZKi3h dqtf+NARpQFCCrYK8/ErqADVBcprbSfZiLsBqV6v59rRArNN+8i1hYIspq2cWMkbil8i 6iTPaiSf/fMBjWNK/L9QSXavC8WqCCut728D5dKhPVzSlzFl9PO71Td3PBGvk3YCqJ8/ +BFA== X-Gm-Message-State: ABy/qLbhAfDieGX+iJiJYuWs95wJVfcIgCMF01YQvJeuuucCulfLDPDo FEpNdcZar2oSwKeMUHpVGlAWUUZD/2Y= X-Google-Smtp-Source: APBJJlE2nxuBMZTc6tsHHVP/zDZfM1zO/qPtnEy+bfYdI+vtC/H0IUdghcKWYcF/n32JcSPB9GeJlvFqcvY= X-Received: from surenb-desktop.mtv.corp.google.com ([2620:15c:211:201:d4d3:7e41:cb80:21ea]) (user=surenb job=sendgmr) by 2002:a05:6902:1616:b0:d12:d6e4:a08e with SMTP id bw22-20020a056902161600b00d12d6e4a08emr70507ybb.5.1690823571188; Mon, 31 Jul 2023 10:12:51 -0700 (PDT) Date: Mon, 31 Jul 2023 10:12:32 -0700 In-Reply-To: <20230731171233.1098105-1-surenb@google.com> Mime-Version: 1.0 References: <20230731171233.1098105-1-surenb@google.com> X-Mailer: git-send-email 2.41.0.487.g6d72f3e995-goog Message-ID: <20230731171233.1098105-7-surenb@google.com> Subject: [PATCH 6/6] mm: move vma locking out of vma_prepare From: Suren Baghdasaryan To: akpm@linux-foundation.org Cc: torvalds@linux-foundation.org, jannh@google.com, willy@infradead.org, liam.howlett@oracle.com, david@redhat.com, peterx@redhat.com, ldufour@linux.ibm.com, vbabka@suse.cz, michel@lespinasse.org, jglisse@google.com, mhocko@suse.com, hannes@cmpxchg.org, dave@stgolabs.net, hughd@google.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, stable@vger.kernel.org, Suren Baghdasaryan , Linus Torvalds Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org vma_prepare() is currently the central place where vmas are being locked before vma_complete() applies changes to them. While this is convenient, it also obscures vma locking and makes it hard to follow the locking rules. Move vma locking out of vma_prepare() and take vma locks explicitly at the locations where vmas are being modified. Suggested-by: Linus Torvalds Signed-off-by: Suren Baghdasaryan --- mm/mmap.c | 26 ++++++++++++++++---------- 1 file changed, 16 insertions(+), 10 deletions(-) diff --git a/mm/mmap.c b/mm/mmap.c index 850a39dee075..e59d83cb1d7a 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -476,16 +476,6 @@ static inline void init_vma_prep(struct vma_prepare *vp, */ static inline void vma_prepare(struct vma_prepare *vp) { - vma_start_write(vp->vma); - if (vp->adj_next) - vma_start_write(vp->adj_next); - if (vp->insert) - vma_start_write(vp->insert); - if (vp->remove) - vma_start_write(vp->remove); - if (vp->remove2) - vma_start_write(vp->remove2); - if (vp->file) { uprobe_munmap(vp->vma, vp->vma->vm_start, vp->vma->vm_end); @@ -650,6 +640,7 @@ int vma_expand(struct vma_iterator *vmi, struct vm_area_struct *vma, bool remove_next = false; struct vma_prepare vp; + vma_start_write(vma); if (next && (vma != next) && (end == next->vm_end)) { int ret; @@ -657,6 +648,7 @@ int vma_expand(struct vma_iterator *vmi, struct vm_area_struct *vma, ret = dup_anon_vma(vma, next); if (ret) return ret; + vma_start_write(next); } init_multi_vma_prep(&vp, vma, NULL, remove_next ? next : NULL, NULL); @@ -708,6 +700,8 @@ int vma_shrink(struct vma_iterator *vmi, struct vm_area_struct *vma, if (vma_iter_prealloc(vmi)) return -ENOMEM; + vma_start_write(vma); + init_vma_prep(&vp, vma); vma_prepare(&vp); vma_adjust_trans_huge(vma, start, end, 0); @@ -946,10 +940,12 @@ struct vm_area_struct *vma_merge(struct vma_iterator *vmi, struct mm_struct *mm, /* Can we merge both the predecessor and the successor? */ if (merge_prev && merge_next && is_mergeable_anon_vma(prev->anon_vma, next->anon_vma, NULL)) { + vma_start_write(next); remove = next; /* case 1 */ vma_end = next->vm_end; err = dup_anon_vma(prev, next); if (curr) { /* case 6 */ + vma_start_write(curr); remove = curr; remove2 = next; if (!next->anon_vma) @@ -958,6 +954,7 @@ struct vm_area_struct *vma_merge(struct vma_iterator *vmi, struct mm_struct *mm, } else if (merge_prev) { /* case 2 */ if (curr) { err = dup_anon_vma(prev, curr); + vma_start_write(curr); if (end == curr->vm_end) { /* case 7 */ remove = curr; } else { /* case 5 */ @@ -969,6 +966,7 @@ struct vm_area_struct *vma_merge(struct vma_iterator *vmi, struct mm_struct *mm, res = next; if (prev && addr < prev->vm_end) { /* case 4 */ vma_end = addr; + vma_start_write(next); adjust = next; adj_start = -(prev->vm_end - addr); err = dup_anon_vma(next, prev); @@ -983,6 +981,7 @@ struct vm_area_struct *vma_merge(struct vma_iterator *vmi, struct mm_struct *mm, vma_pgoff = next->vm_pgoff - pglen; if (curr) { /* case 8 */ vma_pgoff = curr->vm_pgoff; + vma_start_write(curr); remove = curr; err = dup_anon_vma(next, curr); } @@ -996,6 +995,8 @@ struct vm_area_struct *vma_merge(struct vma_iterator *vmi, struct mm_struct *mm, if (vma_iter_prealloc(vmi)) return NULL; + vma_start_write(vma); + init_multi_vma_prep(&vp, vma, adjust, remove, remove2); VM_WARN_ON(vp.anon_vma && adjust && adjust->anon_vma && vp.anon_vma != adjust->anon_vma); @@ -2373,6 +2374,9 @@ int __split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma, if (new->vm_ops && new->vm_ops->open) new->vm_ops->open(new); + vma_start_write(vma); + vma_start_write(new); + init_vma_prep(&vp, vma); vp.insert = new; vma_prepare(&vp); @@ -3078,6 +3082,8 @@ static int do_brk_flags(struct vma_iterator *vmi, struct vm_area_struct *vma, if (vma_iter_prealloc(vmi)) goto unacct_fail; + vma_start_write(vma); + init_vma_prep(&vp, vma); vma_prepare(&vp); vma_adjust_trans_huge(vma, vma->vm_start, addr + len, 0); -- 2.41.0.487.g6d72f3e995-goog