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DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1705566207; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=pe8IQrETqG5sJ0hFhkc64W1l6+nAKA4aDlhTJnXDWtk=; b=SBJmTn8g80S8xKAdpZWPh/c8KSATg87T78tr6m5D14ECkBeTJqRCJfnqu63LsoU1CU2t5Z BaoXLQyzx9nI+IezmXxYukd1V73FEBZ7GsBUFrrd+FiExJjqTVjDwno93GRTNj7/WVhpRI nSv3+o86VTpwX8+wlHsxW+SIEqRopps= From: Yajun Deng To: akpm@linux-foundation.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Yajun Deng Subject: [PATCH] mm/mmap: simplify vma_merge() Date: Thu, 18 Jan 2024 16:23:12 +0800 Message-Id: <20240118082312.2801992-1-yajun.deng@linux.dev> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Queue-Id: 87EAC4000F X-Rspam-User: X-Rspamd-Server: rspam11 X-Stat-Signature: 3x1dadjqao9esdw6eu63tpcjcybpwkno X-HE-Tag: 1705566209-352276 X-HE-Meta: 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 ffe0GZ3a qFpFIZeN6aysam7rnDHT070qSBY7+A4ao03AJJZ6MmTBnyVsdZv2NFKK6ab3FKmYRwm8SzWYRjz/mXch4sqdL2LVVaZ1w2N5/6+gvA4FOe9a22Ic312gY5b5xkZUe5elAzqHD 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: List-Subscribe: List-Unsubscribe: These vma_merge() callers will pass mm, anon_vma and file, they all from vma. There is no need to pass three parameters at the same time. We will find the current vma in vma_merge(). If we pass the original vma to vma_merge(), the current vma is actually the original vma or NULL. So we didn't need to find the current vma with find_vma_intersection(). Pass vma to vma_merge(), and add a check to make sure the current vma is an existing vma. Signed-off-by: Yajun Deng --- mm/mmap.c | 37 +++++++++++++++++-------------------- 1 file changed, 17 insertions(+), 20 deletions(-) diff --git a/mm/mmap.c b/mm/mmap.c index 49d25172eac8..7e00ae4f39e3 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -860,14 +860,16 @@ can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags, * area is returned, or the function will return NULL */ static struct vm_area_struct -*vma_merge(struct vma_iterator *vmi, struct mm_struct *mm, - struct vm_area_struct *prev, unsigned long addr, unsigned long end, - unsigned long vm_flags, struct anon_vma *anon_vma, struct file *file, - pgoff_t pgoff, struct mempolicy *policy, +*vma_merge(struct vma_iterator *vmi, struct vm_area_struct *prev, + struct vm_area_struct *curr, unsigned long addr, unsigned long end, + unsigned long vm_flags, pgoff_t pgoff, struct mempolicy *policy, struct vm_userfaultfd_ctx vm_userfaultfd_ctx, struct anon_vma_name *anon_name) { - struct vm_area_struct *curr, *next, *res; + struct mm_struct *mm = curr->vm_mm; + struct anon_vma *anon_vma = curr->anon_vma; + struct file *file = curr->vm_file; + struct vm_area_struct *next = NULL, *res; struct vm_area_struct *vma, *adjust, *remove, *remove2; struct vm_area_struct *anon_dup = NULL; struct vma_prepare vp; @@ -889,13 +891,12 @@ static struct vm_area_struct return NULL; /* Does the input range span an existing VMA? (cases 5 - 8) */ - curr = find_vma_intersection(mm, prev ? prev->vm_end : 0, end); + if (prev == curr || addr != curr->vm_start || end > curr->vm_end) + curr = NULL; if (!curr || /* cases 1 - 4 */ end == curr->vm_end) /* cases 6 - 8, adjacent VMA */ - next = vma_lookup(mm, end); - else - next = NULL; /* case 5 */ + next = vma_lookup(mm, end); /* NULL case 5 */ if (prev) { vma_start = prev->vm_start; @@ -919,7 +920,6 @@ static struct vm_area_struct /* Verify some invariant that must be enforced by the caller. */ VM_WARN_ON(prev && addr <= prev->vm_start); - VM_WARN_ON(curr && (addr != curr->vm_start || end > curr->vm_end)); VM_WARN_ON(addr >= end); if (!merge_prev && !merge_next) @@ -2424,9 +2424,8 @@ struct vm_area_struct *vma_modify(struct vma_iterator *vmi, pgoff_t pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT); struct vm_area_struct *merged; - merged = vma_merge(vmi, vma->vm_mm, prev, start, end, vm_flags, - vma->anon_vma, vma->vm_file, pgoff, policy, - uffd_ctx, anon_name); + merged = vma_merge(vmi, prev, vma, start, end, vm_flags, + pgoff, policy, uffd_ctx, anon_name); if (merged) return merged; @@ -2456,9 +2455,8 @@ static struct vm_area_struct struct vm_area_struct *vma, unsigned long start, unsigned long end, pgoff_t pgoff) { - return vma_merge(vmi, vma->vm_mm, prev, start, end, vma->vm_flags, - vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma), - vma->vm_userfaultfd_ctx, anon_vma_name(vma)); + return vma_merge(vmi, prev, vma, start, end, vma->vm_flags, pgoff, + vma_policy(vma), vma->vm_userfaultfd_ctx, anon_vma_name(vma)); } /* @@ -2472,10 +2470,9 @@ struct vm_area_struct *vma_merge_extend(struct vma_iterator *vmi, pgoff_t pgoff = vma->vm_pgoff + vma_pages(vma); /* vma is specified as prev, so case 1 or 2 will apply. */ - return vma_merge(vmi, vma->vm_mm, vma, vma->vm_end, vma->vm_end + delta, - vma->vm_flags, vma->anon_vma, vma->vm_file, pgoff, - vma_policy(vma), vma->vm_userfaultfd_ctx, - anon_vma_name(vma)); + return vma_merge(vmi, vma, vma, vma->vm_end, vma->vm_end + delta, + vma->vm_flags, pgoff, vma_policy(vma), + vma->vm_userfaultfd_ctx, anon_vma_name(vma)); } /* -- 2.25.1