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-rw-r--r--mm/page_cgroup.c20
1 files changed, 16 insertions, 4 deletions
diff --git a/mm/page_cgroup.c b/mm/page_cgroup.c
index 3dd8853..6c00814 100644
--- a/mm/page_cgroup.c
+++ b/mm/page_cgroup.c
@@ -284,6 +284,7 @@ static DEFINE_MUTEX(swap_cgroup_mutex);
struct swap_cgroup_ctrl {
struct page **map;
unsigned long length;
+ spinlock_t lock;
};
struct swap_cgroup_ctrl swap_cgroup_ctrl[MAX_SWAPFILES];
@@ -353,16 +354,22 @@ unsigned short swap_cgroup_cmpxchg(swp_entry_t ent,
struct swap_cgroup_ctrl *ctrl;
struct page *mappage;
struct swap_cgroup *sc;
+ unsigned long flags;
+ unsigned short retval;
ctrl = &swap_cgroup_ctrl[type];
mappage = ctrl->map[idx];
sc = page_address(mappage);
sc += pos;
- if (cmpxchg(&sc->id, old, new) == old)
- return old;
+ spin_lock_irqsave(&ctrl->lock, flags);
+ retval = sc->id;
+ if (retval == old)
+ sc->id = new;
else
- return 0;
+ retval = 0;
+ spin_unlock_irqrestore(&ctrl->lock, flags);
+ return retval;
}
/**
@@ -383,13 +390,17 @@ unsigned short swap_cgroup_record(swp_entry_t ent, unsigned short id)
struct page *mappage;
struct swap_cgroup *sc;
unsigned short old;
+ unsigned long flags;
ctrl = &swap_cgroup_ctrl[type];
mappage = ctrl->map[idx];
sc = page_address(mappage);
sc += pos;
- old = xchg(&sc->id, id);
+ spin_lock_irqsave(&ctrl->lock, flags);
+ old = sc->id;
+ sc->id = id;
+ spin_unlock_irqrestore(&ctrl->lock, flags);
return old;
}
@@ -441,6 +452,7 @@ int swap_cgroup_swapon(int type, unsigned long max_pages)
mutex_lock(&swap_cgroup_mutex);
ctrl->length = length;
ctrl->map = array;
+ spin_lock_init(&ctrl->lock);
if (swap_cgroup_prepare(type)) {
/* memory shortage */
ctrl->map = NULL;
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