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mm/mempolicy: remove or narrow the lock on current

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It is not necessary to hold the lock of current when setting nodemask of
a new policy.

Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Link: https://lkml.kernel.org/r/20200921040416.86185-1-richard.weiyang@linux.alibaba.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Wei Yang 2020-10-13 16:57:08 -07:00 committed by Linus Torvalds
parent 1100262037
commit 78b132e9ba
1 changed files with 1 additions and 4 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

5
mm/mempolicy.c
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@ -875,13 +875,12 @@ static long do_set_mempolicy(unsigned short mode, unsigned short flags,
goto out; goto out;
} }
task_lock(current);
ret = mpol_set_nodemask(new, nodes, scratch); ret = mpol_set_nodemask(new, nodes, scratch);
if (ret) { if (ret) {
task_unlock(current);
mpol_put(new); mpol_put(new);
goto out; goto out;
} }
task_lock(current);
old = current->mempolicy; old = current->mempolicy;
current->mempolicy = new; current->mempolicy = new;
if (new && new->mode == MPOL_INTERLEAVE) if (new && new->mode == MPOL_INTERLEAVE)
@ -1324,9 +1323,7 @@ static long do_mbind(unsigned long start, unsigned long len,
NODEMASK_SCRATCH(scratch); NODEMASK_SCRATCH(scratch);
if (scratch) { if (scratch) {
mmap_write_lock(mm); mmap_write_lock(mm);
task_lock(current);
err = mpol_set_nodemask(new, nmask, scratch); err = mpol_set_nodemask(new, nmask, scratch);
task_unlock(current);
if (err) if (err)
mmap_write_unlock(mm); mmap_write_unlock(mm);
} else } else