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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>
hifive-unleashed-5.1
Davidlohr Bueso 2014-01-21 15:49:16 -08:00 committed by Linus Torvalds
parent 363ee17f0f
commit 1f1cd7054f
1 changed files with 11 additions and 7 deletions
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18
mm/mlock.c
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@ -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);