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authorDavidlohr Bueso <davidlohr@hp.com>2014-01-21 15:49:16 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2014-01-21 16:19:44 -0800
commit1f1cd7054fe7f45e65dd4963d0a38e5ab7a57cae (patch)
tree3296b8809eca9c4eb6db72a4d00d2c534b6c8db2
parent363ee17f0f405faff74d9aaf93d21d5f41d5102d (diff)
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: Davidlohr Bueso <davidlohr@hp.com> Cc: Rik van Riel <riel@redhat.com> Reviewed-by: Michel Lespinasse <walken@google.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/mlock.c18
1 files changed, 11 insertions, 7 deletions
diff --git a/mm/mlock.c b/mm/mlock.c
index 192e6eebe4f..10819ed4df3 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -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);