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Commit 2c7c3a7d authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds
Browse files

mempolicy: kill do_set_mempolicy()->down_write(&mm->mmap_sem) 



Remove down_write(&mm->mmap_sem) in do_set_mempolicy(). This logic
was never correct and it is no longer needed, see the previous patch.

Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 498f2371

mm/mempolicy.c

+1 −14
Original line number Diff line number Diff line
@@ -802,7 +802,6 @@ static long do_set_mempolicy(unsigned short mode, unsigned short flags, 
			     nodemask_t *nodes)

{

	struct mempolicy *new, *old;

	struct mm_struct *mm = current->mm;

	NODEMASK_SCRATCH(scratch);

	int ret;
@@ -814,20 +813,11 @@ static long do_set_mempolicy(unsigned short mode, unsigned short flags, 
		ret = PTR_ERR(new);

		goto out;

	}

	/*

	 * prevent changing our mempolicy while show_numa_maps()

	 * is using it.

	 * Note:  do_set_mempolicy() can be called at init time

	 * with no 'mm'.

	 */

	if (mm)

		down_write(&mm->mmap_sem);



	task_lock(current);

	ret = mpol_set_nodemask(new, nodes, scratch);

	if (ret) {

		task_unlock(current);

		if (mm)

			up_write(&mm->mmap_sem);

		mpol_put(new);

		goto out;

	}
@@ -837,9 +827,6 @@ static long do_set_mempolicy(unsigned short mode, unsigned short flags, 
	    nodes_weight(new->v.nodes))

		current->il_next = first_node(new->v.nodes);

	task_unlock(current);

	if (mm)

		up_write(&mm->mmap_sem);



	mpol_put(old);

	ret = 0;

out: