Commit 78b132e9 authored by Wei Yang's avatar Wei Yang Committed by Linus Torvalds
Browse files

mm/mempolicy: remove or narrow the lock on current 



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

Signed-off-by: default avatarWei Yang <richard.weiyang@linux.alibaba.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Link: https://lkml.kernel.org/r/20200921040416.86185-1-richard.weiyang@linux.alibaba.com


Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 11002620

mm/mempolicy.c

+1 −4
Original line number Diff line number Diff line
@@ -875,13 +875,12 @@ static long do_set_mempolicy(unsigned short mode, unsigned short flags, 
		goto out;

	}



	task_lock(current);

	ret = mpol_set_nodemask(new, nodes, scratch);

	if (ret) {

		task_unlock(current);

		mpol_put(new);

		goto out;

	}

	task_lock(current);

	old = current->mempolicy;

	current->mempolicy = new;

	if (new && new->mode == MPOL_INTERLEAVE)
@@ -1324,9 +1323,7 @@ static long do_mbind(unsigned long start, unsigned long len, 
		NODEMASK_SCRATCH(scratch);

		if (scratch) {

			mmap_write_lock(mm);

			task_lock(current);

			err = mpol_set_nodemask(new, nmask, scratch);

			task_unlock(current);

			if (err)

				mmap_write_unlock(mm);

		} else