Commit 1f1cd705 authored by Davidlohr Bueso's avatar Davidlohr Bueso Committed by Linus Torvalds
Browse files

mm/mlock: prepare params outside critical region 



All mlock related syscalls prepare lock limits, lengths and start
parameters with the mmap_sem held.  Move this logic outside of the
critical region.  For the case of mlock, continue incrementing the
amount already locked by mm->locked_vm with the rwsem taken.

Signed-off-by: default avatarDavidlohr Bueso <davidlohr@hp.com>
Cc: Rik van Riel <riel@redhat.com>
Reviewed-by: default avatarMichel Lespinasse <walken@google.com>
Acked-by: default avatarVlastimil 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 363ee17f

mm/mlock.c

+11 −7
Original line number Diff line number Diff line
@@ -709,19 +709,21 @@ SYSCALL_DEFINE2(mlock, unsigned long, start, size_t, len) 


	lru_add_drain_all();	/* flush pagevec */



	down_write(&current->mm->mmap_sem);

	len = PAGE_ALIGN(len + (start & ~PAGE_MASK));

	start &= PAGE_MASK;



	locked = len >> PAGE_SHIFT;

	locked += current->mm->locked_vm;



	lock_limit = rlimit(RLIMIT_MEMLOCK);

	lock_limit >>= PAGE_SHIFT;

	locked = len >> PAGE_SHIFT;



	down_write(&current->mm->mmap_sem);



	locked += current->mm->locked_vm;



	/* check against resource limits */

	if ((locked <= lock_limit) || capable(CAP_IPC_LOCK))

		error = do_mlock(start, len, 1);



	up_write(&current->mm->mmap_sem);

	if (!error)

		error = __mm_populate(start, len, 0);
@@ -732,11 +734,13 @@ SYSCALL_DEFINE2(munlock, unsigned long, start, size_t, len) 
{

	int ret;



	down_write(&current->mm->mmap_sem);

	len = PAGE_ALIGN(len + (start & ~PAGE_MASK));

	start &= PAGE_MASK;



	down_write(&current->mm->mmap_sem);

	ret = do_mlock(start, len, 0);

	up_write(&current->mm->mmap_sem);



	return ret;

}
@@ -781,12 +785,12 @@ SYSCALL_DEFINE1(mlockall, int, flags) 
	if (flags & MCL_CURRENT)

		lru_add_drain_all();	/* flush pagevec */



	down_write(&current->mm->mmap_sem);



	lock_limit = rlimit(RLIMIT_MEMLOCK);

	lock_limit >>= PAGE_SHIFT;



	ret = -ENOMEM;

	down_write(&current->mm->mmap_sem);



	if (!(flags & MCL_CURRENT) || (current->mm->total_vm <= lock_limit) ||

	    capable(CAP_IPC_LOCK))

		ret = do_mlockall(flags);

CRA Git | Maintained and supported by SUSTech CRA and CCSE