mm: add new mmget() helper
Apart from adding the helper function itself, the rest of the kernel is
converted mechanically using:
git grep -l 'atomic_inc.*mm_users' | xargs sed -i 's/atomic_inc(&\(.*\)->mm_users);/mmget\(\1\);/'
git grep -l 'atomic_inc.*mm_users' | xargs sed -i 's/atomic_inc(&\(.*\)\.mm_users);/mmget\(\&\1\);/'
This is needed for a later patch that hooks into the helper, but might
be a worthwhile cleanup on its own.
(Michal Hocko provided most of the kerneldoc comment.)
Link: http://lkml.kernel.org/r/20161218123229.22952-2-vegard.nossum@oracle.com
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 2cac12c..7a0713b 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1671,7 +1671,7 @@ int try_to_unuse(unsigned int type, bool frontswap,
* that.
*/
start_mm = &init_mm;
- atomic_inc(&init_mm.mm_users);
+ mmget(&init_mm);
/*
* Keep on scanning until all entries have gone. Usually,
@@ -1720,7 +1720,7 @@ int try_to_unuse(unsigned int type, bool frontswap,
if (atomic_read(&start_mm->mm_users) == 1) {
mmput(start_mm);
start_mm = &init_mm;
- atomic_inc(&init_mm.mm_users);
+ mmget(&init_mm);
}
/*
@@ -1757,8 +1757,8 @@ int try_to_unuse(unsigned int type, bool frontswap,
struct mm_struct *prev_mm = start_mm;
struct mm_struct *mm;
- atomic_inc(&new_start_mm->mm_users);
- atomic_inc(&prev_mm->mm_users);
+ mmget(new_start_mm);
+ mmget(prev_mm);
spin_lock(&mmlist_lock);
while (swap_count(*swap_map) && !retval &&
(p = p->next) != &start_mm->mmlist) {
@@ -1781,7 +1781,7 @@ int try_to_unuse(unsigned int type, bool frontswap,
if (set_start_mm && *swap_map < swcount) {
mmput(new_start_mm);
- atomic_inc(&mm->mm_users);
+ mmget(mm);
new_start_mm = mm;
set_start_mm = 0;
}