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From: Yang Shi <yang.shi@linux.alibaba.com>
To: akpm@linux-foundation.org
Cc: yang.shi@linux.alibaba.com, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org
Subject: [RFC PATCH 2/8] mm: mmap: pass atomic parameter to do_munmap() call sites
Date: Wed, 21 Mar 2018 05:31:20 +0800	[thread overview]
Message-ID: <1521581486-99134-3-git-send-email-yang.shi@linux.alibaba.com> (raw)
In-Reply-To: <1521581486-99134-1-git-send-email-yang.shi@linux.alibaba.com>

It looks safe to release mmap_sem in the middle for vm_munmap and brk,
so passing "false" to do_munmap() call.
However it sounds not safe to mmap_region() which is called by
SyS_mmap().

Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
---
 mm/mmap.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/mm/mmap.c b/mm/mmap.c
index ad6ae7a..374e4ec 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -225,7 +225,7 @@ static struct vm_area_struct *remove_vma(struct vm_area_struct *vma)
 
 	/* Always allow shrinking brk. */
 	if (brk <= mm->brk) {
-		if (!do_munmap(mm, newbrk, oldbrk-newbrk, &uf))
+		if (!do_munmap(mm, newbrk, oldbrk-newbrk, &uf, false))
 			goto set_brk;
 		goto out;
 	}
@@ -1643,7 +1643,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
 	/* Clear old maps */
 	while (find_vma_links(mm, addr, addr + len, &prev, &rb_link,
 			      &rb_parent)) {
-		if (do_munmap(mm, addr, len, uf))
+		if (do_munmap(mm, addr, len, uf, true))
 			return -ENOMEM;
 	}
 
@@ -2778,7 +2778,7 @@ int vm_munmap(unsigned long start, size_t len)
 	if (down_write_killable(&mm->mmap_sem))
 		return -EINTR;
 
-	ret = do_munmap(mm, start, len, &uf);
+	ret = do_munmap(mm, start, len, &uf, false);
 	up_write(&mm->mmap_sem);
 	userfaultfd_unmap_complete(mm, &uf);
 	return ret;
@@ -2945,7 +2945,7 @@ static int do_brk_flags(unsigned long addr, unsigned long request, unsigned long
 	 */
 	while (find_vma_links(mm, addr, addr + len, &prev, &rb_link,
 			      &rb_parent)) {
-		if (do_munmap(mm, addr, len, uf))
+		if (do_munmap(mm, addr, len, uf, false))
 			return -ENOMEM;
 	}
 
-- 
1.8.3.1

  parent reply	other threads:[~2018-03-20 21:32 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-20 21:31 [RFC PATCH 0/8] Drop mmap_sem during unmapping large map Yang Shi
2018-03-20 21:31 ` [RFC PATCH 1/8] mm: mmap: unmap large mapping by section Yang Shi
2018-03-21 13:08   ` Michal Hocko
2018-03-21 16:31     ` Yang Shi
2018-03-21 17:29       ` Matthew Wilcox
2018-03-21 21:45         ` Yang Shi
2018-03-21 22:15           ` Matthew Wilcox
2018-03-21 22:40             ` Yang Shi
2018-03-21 22:46           ` Matthew Wilcox
2018-03-22 15:32             ` Laurent Dufour
2018-03-22 15:40               ` Matthew Wilcox
2018-03-22 15:54                 ` Laurent Dufour
2018-03-22 16:05                   ` Matthew Wilcox
2018-03-22 16:18                     ` Laurent Dufour
2018-03-22 16:46                       ` Yang Shi
2018-03-23 13:03                         ` Laurent Dufour
2018-03-22 16:51                       ` Matthew Wilcox
2018-03-22 16:49                     ` Yang Shi
2018-03-22 17:34         ` Yang Shi
2018-03-22 18:48           ` Matthew Wilcox
2018-03-24 18:24         ` Jerome Glisse
2018-03-21 13:14   ` Michal Hocko
2018-03-21 16:50     ` Yang Shi
2018-03-21 17:16       ` Yang Shi
2018-03-21 21:23         ` Michal Hocko
2018-03-21 22:36           ` Yang Shi
2018-03-22  9:10             ` Michal Hocko
2018-03-22 16:06               ` Yang Shi
2018-03-22 16:12                 ` Michal Hocko
2018-03-22 16:13                 ` Matthew Wilcox
2018-03-22 16:28                   ` Laurent Dufour
2018-03-22 16:36                     ` David Laight
2018-03-20 21:31 ` Yang Shi [this message]
2018-03-20 21:31 ` [RFC PATCH 3/8] mm: mremap: pass atomic parameter to do_munmap() Yang Shi
2018-03-20 21:31 ` [RFC PATCH 4/8] mm: nommu: add " Yang Shi
2018-03-20 21:31 ` [RFC PATCH 5/8] ipc: shm: pass " Yang Shi
2018-03-20 21:31 ` [RFC PATCH 6/8] fs: proc/vmcore: " Yang Shi
2018-03-20 21:31 ` [RFC PATCH 7/8] x86: mpx: " Yang Shi
2018-03-20 22:35   ` Thomas Gleixner
2018-03-21 16:53     ` Yang Shi
2018-03-20 21:31 ` [RFC PATCH 8/8] x86: vma: " Yang Shi

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