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 287F4C76195 for ; Tue, 21 Mar 2023 21:12:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230005AbjCUVMg (ORCPT ); Tue, 21 Mar 2023 17:12:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52380 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229579AbjCUVMc (ORCPT ); Tue, 21 Mar 2023 17:12:32 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 47329580C5 for ; Tue, 21 Mar 2023 14:12:10 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id E2018B81A37 for ; Tue, 21 Mar 2023 21:12:08 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 77AE8C433EF; Tue, 21 Mar 2023 21:12:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1679433127; bh=s9EREJTplynCZhPvYmx3CjBv9/yLErTLUs+bowMViC8=; h=Date:To:From:Subject:From; b=KBbSrPvgJfkzTsD8XmJ4ZUkXeEeO5irLcKS1bbdV/rzFYkj21avU4Zj3yuITMBAyB Rx/WZnXdFUDEfGvzHIMGfcn/RaqzeDf9JGAvpZftKPU1AtMChUnCqTPuI/MG3BvIde zhkYu+x46YS3eQYgpYrUScIVAhD1ZIEfZuhL3K98= Date: Tue, 21 Mar 2023 14:12:06 -0700 To: mm-commits@vger.kernel.org, willy@infradead.org, vernon2gm@gmail.com, vbabka@suse.cz, liam.howlett@oracle.com, david@redhat.com, lstoakes@gmail.com, akpm@linux-foundation.org From: Andrew Morton Subject: + mm-mmap-vma_merge-init-cleanup-be-explicit-about-the-non-mergeable-case.patch added to mm-unstable branch Message-Id: <20230321211207.77AE8C433EF@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: mm/mmap/vma_merge: init cleanup, be explicit about the non-mergeable case has been added to the -mm mm-unstable branch. Its filename is mm-mmap-vma_merge-init-cleanup-be-explicit-about-the-non-mergeable-case.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-mmap-vma_merge-init-cleanup-be-explicit-about-the-non-mergeable-case.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Lorenzo Stoakes Subject: mm/mmap/vma_merge: init cleanup, be explicit about the non-mergeable case Date: Tue, 21 Mar 2023 20:45:58 +0000 Reorder the initial variables sensibly and set vma_start and vm_pgoff there rather than later so all initial values are set at the same time meaning we don't have to set these later. Rather than setting err = -1 and only resetting if we hit merge cases, explicitly check the non-mergeable case to make it abundantly clear that we only proceed with the rest if something is mergeable, default err to 0 and only update if an error might occur. Move the merge_prev, merge_next cases closer to the logic determining curr, next. This has no functional impact. Link: https://lkml.kernel.org/r/f5e27d1bb9259b7ef7a45099a838e47fbaaad3ab.1679431180.git.lstoakes@gmail.com Signed-off-by: Lorenzo Stoakes Cc: David Hildenbrand Cc: Liam Howlett Cc: Matthew Wilcox (Oracle) Cc: Vernon Yang Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- mm/mmap.c | 55 ++++++++++++++++++++++++---------------------------- 1 file changed, 26 insertions(+), 29 deletions(-) --- a/mm/mmap.c~mm-mmap-vma_merge-init-cleanup-be-explicit-about-the-non-mergeable-case +++ a/mm/mmap.c @@ -909,18 +909,18 @@ struct vm_area_struct *vma_merge(struct struct vm_userfaultfd_ctx vm_userfaultfd_ctx, struct anon_vma_name *anon_name) { - pgoff_t pglen = (end - addr) >> PAGE_SHIFT; - pgoff_t vma_pgoff; struct vm_area_struct *curr, *next, *res; struct vm_area_struct *vma, *adjust, *remove, *remove2; - int err = -1; + struct vma_prepare vp; + int err = 0; bool merge_prev = false; bool merge_next = false; bool vma_expanded = false; - struct vma_prepare vp; + unsigned long vma_start = prev ? prev->vm_start : addr; unsigned long vma_end = end; + pgoff_t vma_pgoff = prev ? prev->vm_pgoff : 0; + pgoff_t pglen = (end - addr) >> PAGE_SHIFT; long adj_start = 0; - unsigned long vma_start = addr; validate_mm(mm); /* @@ -940,6 +940,23 @@ struct vm_area_struct *vma_merge(struct /* Is there a VMA next to a hole (case 1 - 3) or prev (4)? */ next = vma_lookup(mm, end); + /* Can we merge the predecessor? */ + if (prev && addr == prev->vm_end && mpol_equal(vma_policy(prev), policy) + && can_vma_merge_after(prev, vm_flags, anon_vma, file, + pgoff, vm_userfaultfd_ctx, anon_name)) { + merge_prev = true; + vma_prev(vmi); + } + + /* Can we merge the successor? */ + merge_next = next && mpol_equal(policy, vma_policy(next)) && + can_vma_merge_before(next, vm_flags, + anon_vma, file, pgoff+pglen, + vm_userfaultfd_ctx, anon_name); + + if (!merge_prev && !merge_next) + return NULL; /* Not mergeable. */ + /* * By default, we return prev. Cases 3, 4, 8 will instead return next * and cases 3, 8 will also update vma to point at next. @@ -951,26 +968,6 @@ struct vm_area_struct *vma_merge(struct VM_WARN_ON(curr && (addr != curr->vm_start || end > curr->vm_end)); VM_WARN_ON(addr >= end); - if (prev) { - vma_start = prev->vm_start; - vma_pgoff = prev->vm_pgoff; - /* Can we merge the predecessor? */ - if (prev->vm_end == addr && mpol_equal(vma_policy(prev), policy) - && can_vma_merge_after(prev, vm_flags, anon_vma, file, - pgoff, vm_userfaultfd_ctx, anon_name)) { - merge_prev = true; - vma_prev(vmi); - } - } - - /* Can we merge the successor? */ - if (next && mpol_equal(policy, vma_policy(next)) && - can_vma_merge_before(next, vm_flags, - anon_vma, file, pgoff+pglen, - vm_userfaultfd_ctx, anon_name)) { - merge_next = true; - } - remove = remove2 = adjust = NULL; /* Can we merge both the predecessor and the successor? */ if (merge_prev && merge_next && @@ -985,7 +982,7 @@ struct vm_area_struct *vma_merge(struct err = dup_anon_vma(prev, curr); } } else if (merge_prev) { - err = 0; /* case 2 */ + /* case 2 */ if (curr) { err = dup_anon_vma(prev, curr); if (end == curr->vm_end) { /* case 7 */ @@ -995,7 +992,7 @@ struct vm_area_struct *vma_merge(struct adj_start = (end - curr->vm_start); } } - } else if (merge_next) { + } else { /* merge_next */ res = next; if (prev && addr < prev->vm_end) { /* case 4 */ vma_end = addr; @@ -1011,7 +1008,7 @@ struct vm_area_struct *vma_merge(struct vma_start = addr; vma_end = next->vm_end; vma_pgoff = next->vm_pgoff; - err = 0; + if (curr) { /* case 8 */ vma_pgoff = curr->vm_pgoff; remove = curr; @@ -1020,7 +1017,7 @@ struct vm_area_struct *vma_merge(struct } } - /* Cannot merge or error in anon_vma clone */ + /* Error in anon_vma clone. */ if (err) return NULL; _ Patches currently in -mm which might be from lstoakes@gmail.com are mm-prefer-xxx_page-alloc-free-functions-for-order-0-pages.patch mm-refactor-do_fault_around.patch mm-pefer-fault_around_pages-to-fault_around_bytes.patch fs-proc-kcore-avoid-bounce-buffer-for-ktext-data.patch mm-vmalloc-use-rwsem-mutex-for-vmap_area_lock-and-vmap_block-lock.patch fs-proc-kcore-convert-read_kcore-to-read_kcore_iter.patch mm-vmalloc-convert-vread-to-vread_iter.patch maintainers-add-myself-as-vmalloc-reviewer.patch mm-remove-unused-vmf_insert_mixed_prot.patch mm-remove-vmf_insert_pfn_xxx_prot-for-huge-page-table-entries.patch drm-ttm-remove-comment-referencing-now-removed-vmf_insert_mixed_prot.patch mm-mmap-vma_merge-further-improve-prev-next-vma-naming.patch mm-mmap-vma_merge-set-next-to-null-if-not-applicable.patch mm-mmap-vma_merge-extend-invariants-avoid-invalid-res-vma.patch mm-mmap-vma_merge-init-cleanup-be-explicit-about-the-non-mergeable-case.patch