Commit 8d90274b authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds
Browse files

mempolicy: sanitize the usage of get_task_policy() 



Cleanup + preparation. Every user of get_task_policy() calls it
unconditionally, even if it is not going to use the result.

get_task_policy() is cheap but still this does not look clean, plus
the code looks simpler if get_task_policy() is called only when this
is really needed.

Note: I hope this is correct, but it is not clear why vma_policy_mof()
doesn't fall back to get_task_policy() if ->get_policy() returns NULL.

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 f15ca78e

mm/mempolicy.c

+14 −11
Original line number Original line Diff line number Diff line
@@ -1621,14 +1621,11 @@ COMPAT_SYSCALL_DEFINE6(mbind, compat_ulong_t, start, compat_ulong_t, len, 
struct mempolicy *get_vma_policy(struct task_struct *task,

struct mempolicy *get_vma_policy(struct task_struct *task,

		struct vm_area_struct *vma, unsigned long addr)

		struct vm_area_struct *vma, unsigned long addr)

{

{

	struct mempolicy *pol = get_task_policy(task);

	struct mempolicy *pol = NULL;





	if (vma) {

	if (vma) {

		if (vma->vm_ops && vma->vm_ops->get_policy) {

		if (vma->vm_ops && vma->vm_ops->get_policy) {

			struct mempolicy *vpol = vma->vm_ops->get_policy(vma,

			pol = vma->vm_ops->get_policy(vma, addr);

									addr);

			if (vpol)

				pol = vpol;

		} else if (vma->vm_policy) {

		} else if (vma->vm_policy) {

			pol = vma->vm_policy;

			pol = vma->vm_policy;
@@ -1643,12 +1640,15 @@ struct mempolicy *get_vma_policy(struct task_struct *task, 
		}

		}

	}

	}





	if (!pol)

		pol = get_task_policy(task);



	return pol;

	return pol;

}

}





bool vma_policy_mof(struct task_struct *task, struct vm_area_struct *vma)

bool vma_policy_mof(struct task_struct *task, struct vm_area_struct *vma)

{

{

	struct mempolicy *pol = get_task_policy(task);

	struct mempolicy *pol = NULL;





	if (vma) {

	if (vma) {

		if (vma->vm_ops && vma->vm_ops->get_policy) {

		if (vma->vm_ops && vma->vm_ops->get_policy) {
@@ -1660,11 +1660,14 @@ bool vma_policy_mof(struct task_struct *task, struct vm_area_struct *vma) 
			mpol_cond_put(pol);

			mpol_cond_put(pol);





			return ret;

			return ret;

		} else if (vma->vm_policy) {

			pol = vma->vm_policy;

		}

		}



		pol = vma->vm_policy;

	}

	}





	if (!pol)

		pol = get_task_policy(task);



	return pol->flags & MPOL_F_MOF;

	return pol->flags & MPOL_F_MOF;

}

}
@@ -2068,12 +2071,12 @@ retry_cpuset: 
 */

 */

struct page *alloc_pages_current(gfp_t gfp, unsigned order)

struct page *alloc_pages_current(gfp_t gfp, unsigned order)

{

{

	struct mempolicy *pol = get_task_policy(current);

	struct mempolicy *pol = &default_policy;

	struct page *page;

	struct page *page;

	unsigned int cpuset_mems_cookie;

	unsigned int cpuset_mems_cookie;





	if (in_interrupt() || (gfp & __GFP_THISNODE))

	if (!in_interrupt() && !(gfp & __GFP_THISNODE))

		pol = &default_policy;

		pol = get_task_policy(current);





retry_cpuset:

retry_cpuset:

	cpuset_mems_cookie = read_mems_allowed_begin();

	cpuset_mems_cookie = read_mems_allowed_begin();

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