[PATCH] do not limit locked memory when RLIMIT_MEMLOCK is RLIM_INFINITY

[Herbert van den Bergh <Herbert.van.den.Bergh@oracle.com>]

This patch fixes a bug in mm/mlock.c on 32-bit architectures that prevents
a user from locking more than 4GB of shared memory, or allocating more
than 4GB of shared memory in hugepages, when rlim[RLIMIT_MEMLOCK] is
set to RLIM_INFINITY.

Signed-off-by: Herbert van den Bergh <herbert.van.den.bergh@oracle.com>
Acked-by: Chris Mason <chris.mason@oracle.com>

--- linux-2.6.22-rc6/mm/mlock.c.orig    2007-06-26 15:17:22.000000000 -0700
+++ linux-2.6.22-rc6/mm/mlock.c    2007-06-28 11:18:48.000000000 -0700
@@ -244,9 +244,12 @@ int user_shm_lock(size_t size, struct us
 
     locked = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
     lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
+    if (lock_limit == RLIM_INFINITY)
+        allowed = 1;
     lock_limit >>= PAGE_SHIFT;
     spin_lock(&shmlock_user_lock);
-    if (locked + user->locked_shm > lock_limit && !capable(CAP_IPC_LOCK))
+    if (!allowed &&
+        locked + user->locked_shm > lock_limit && !capable(CAP_IPC_LOCK))
         goto out;
     get_uid(user);
     user->locked_shm += locked;

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