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Commit 363ee17f authored by Davidlohr Bueso's avatar Davidlohr Bueso Committed by Linus Torvalds
Browse files

mm/mmap.c: add mlock_future_check() helper 



Both do_brk and do_mmap_pgoff verify that we are actually capable of
locking future pages if the corresponding VM_LOCKED flags are used.
Encapsulate this logic into a single mlock_future_check() helper
function.

Signed-off-by: default avatarDavidlohr Bueso <davidlohr@hp.com>
Cc: Rik van Riel <riel@redhat.com>
Reviewed-by: default avatarMichel Lespinasse <walken@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 49f0ce5f

mm/mmap.c

+23 −22
Original line number Diff line number Diff line
@@ -1191,6 +1191,24 @@ static inline unsigned long round_hint_to_min(unsigned long hint) 
	return hint;

}



static inline int mlock_future_check(struct mm_struct *mm,

				     unsigned long flags,

				     unsigned long len)

{

	unsigned long locked, lock_limit;



	/*  mlock MCL_FUTURE? */

	if (flags & VM_LOCKED) {

		locked = len >> PAGE_SHIFT;

		locked += mm->locked_vm;

		lock_limit = rlimit(RLIMIT_MEMLOCK);

		lock_limit >>= PAGE_SHIFT;

		if (locked > lock_limit && !capable(CAP_IPC_LOCK))

			return -EAGAIN;

	}

	return 0;

}



/*

 * The caller must hold down_write(&current->mm->mmap_sem).

 */
@@ -1252,16 +1270,8 @@ unsigned long do_mmap_pgoff(struct file *file, unsigned long addr, 
		if (!can_do_mlock())

			return -EPERM;



	/* mlock MCL_FUTURE? */

	if (vm_flags & VM_LOCKED) {

		unsigned long locked, lock_limit;

		locked = len >> PAGE_SHIFT;

		locked += mm->locked_vm;

		lock_limit = rlimit(RLIMIT_MEMLOCK);

		lock_limit >>= PAGE_SHIFT;

		if (locked > lock_limit && !capable(CAP_IPC_LOCK))

	if (mlock_future_check(mm, vm_flags, len))

		return -EAGAIN;

	}



	if (file) {

		struct inode *inode = file_inode(file);
@@ -2592,18 +2602,9 @@ static unsigned long do_brk(unsigned long addr, unsigned long len) 
	if (error & ~PAGE_MASK)

		return error;



	/*

	 * mlock MCL_FUTURE?

	 */

	if (mm->def_flags & VM_LOCKED) {

		unsigned long locked, lock_limit;

		locked = len >> PAGE_SHIFT;

		locked += mm->locked_vm;

		lock_limit = rlimit(RLIMIT_MEMLOCK);

		lock_limit >>= PAGE_SHIFT;

		if (locked > lock_limit && !capable(CAP_IPC_LOCK))

			return -EAGAIN;

	}

	error = mlock_future_check(mm, mm->def_flags, len);

	if (error)

		return error;



	/*

	 * mm->mmap_sem is required to protect against another thread