mm: fix atomic_t overflow in vm

The atomic_t type is 32bit but a 64bit system can have more than 2^32
pages of virtual address space available.  Without this we overflow on
ludicrously large mappings

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 6 insertions, 6 deletions

diff --git a/mm/mmap.c b/mm/mmap.c
index fac6633..669499e 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -80,7 +80,7 @@ EXPORT_SYMBOL(vm_get_page_prot);
 int sysctl_overcommit_memory = OVERCOMMIT_GUESS;  /* heuristic overcommit */
 int sysctl_overcommit_ratio = 50;	/* default is 50% */
 int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT;
-atomic_t vm_committed_space = ATOMIC_INIT(0);
+atomic_long_t vm_committed_space = ATOMIC_LONG_INIT(0);
 
 /*
  * Check that a process has enough memory to allocate a new virtual
@@ -177,7 +177,7 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
 	 * cast `allowed' as a signed long because vm_committed_space
 	 * sometimes has a negative value
 	 */
-	if (atomic_read(&vm_committed_space) < (long)allowed)
+	if (atomic_long_read(&vm_committed_space) < (long)allowed)
 		return 0;
 error:
 	vm_unacct_memory(pages);
diff --git a/mm/nommu.c b/mm/nommu.c
index ef8c62c..dca93fc 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -39,7 +39,7 @@ struct page *mem_map;
 unsigned long max_mapnr;
 unsigned long num_physpages;
 unsigned long askedalloc, realalloc;
-atomic_t vm_committed_space = ATOMIC_INIT(0);
+atomic_long_t vm_committed_space = ATOMIC_LONG_INIT(0);
 int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */
 int sysctl_overcommit_ratio = 50; /* default is 50% */
 int sysctl_max_map_count = DEFAULT_MAX_MAP_COUNT;
@@ -1410,7 +1410,7 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
 	 * cast `allowed' as a signed long because vm_committed_space
 	 * sometimes has a negative value
 	 */
-	if (atomic_read(&vm_committed_space) < (long)allowed)
+	if (atomic_long_read(&vm_committed_space) < (long)allowed)
 		return 0;
 error:
 	vm_unacct_memory(pages);
diff --git a/mm/swap.c b/mm/swap.c
index 91e1944..45c9f25 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -503,7 +503,7 @@ void vm_acct_memory(long pages)
 	local = &__get_cpu_var(committed_space);
 	*local += pages;
 	if (*local > ACCT_THRESHOLD || *local < -ACCT_THRESHOLD) {
-		atomic_add(*local, &vm_committed_space);
+		atomic_long_add(*local, &vm_committed_space);
 		*local = 0;
 	}
 	preempt_enable();
@@ -520,7 +520,7 @@ static int cpu_swap_callback(struct notifier_block *nfb,
 
 	committed = &per_cpu(committed_space, (long)hcpu);
 	if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) {
-		atomic_add(*committed, &vm_committed_space);
+		atomic_long_add(*committed, &vm_committed_space);
 		*committed = 0;
 		drain_cpu_pagevecs((long)hcpu);
 	}