From 45fc5d72f19903891b817e71a95b5cf82f31ea1e Mon Sep 17 00:00:00 2001 From: Davidlohr Bueso Date: Tue, 17 Dec 2013 10:45:07 +1100 Subject: [PATCH] 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 Cc: Rik van Riel Reviewed-by: Michel Lespinasse Acked-by: Vlastimil Babka Signed-off-by: Andrew Morton --- mm/mlock.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) diff --git a/mm/mlock.c b/mm/mlock.c index d480cd6fc475..aa7de13d9a87 100644 --- a/mm/mlock.c +++ b/mm/mlock.c @@ -689,19 +689,21 @@ SYSCALL_DEFINE2(mlock, unsigned long, start, size_t, len) lru_add_drain_all(); /* flush pagevec */ - down_write(¤t->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(¤t->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(¤t->mm->mmap_sem); if (!error) error = __mm_populate(start, len, 0); @@ -712,11 +714,13 @@ SYSCALL_DEFINE2(munlock, unsigned long, start, size_t, len) { int ret; - down_write(¤t->mm->mmap_sem); len = PAGE_ALIGN(len + (start & ~PAGE_MASK)); start &= PAGE_MASK; + + down_write(¤t->mm->mmap_sem); ret = do_mlock(start, len, 0); up_write(¤t->mm->mmap_sem); + return ret; } @@ -761,12 +765,12 @@ SYSCALL_DEFINE1(mlockall, int, flags) if (flags & MCL_CURRENT) lru_add_drain_all(); /* flush pagevec */ - down_write(¤t->mm->mmap_sem); - lock_limit = rlimit(RLIMIT_MEMLOCK); lock_limit >>= PAGE_SHIFT; ret = -ENOMEM; + down_write(¤t->mm->mmap_sem); + if (!(flags & MCL_CURRENT) || (current->mm->total_vm <= lock_limit) || capable(CAP_IPC_LOCK)) ret = do_mlockall(flags); -- 2.39.5