aboutsummaryrefslogtreecommitdiff
path: root/mm
diff options
context:
space:
mode:
authorSebastian Andrzej Siewior <bigeasy@linutronix.de>2018-08-21 21:55:31 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-08-22 10:52:46 -0700
commite58dd0de5eadf145895b13451a1fef8ef03946eb (patch)
treef5db856cd6e69abf35e136e8c2666469ac6b51d3 /mm
parentcedc5b6aab493f6b1b1d381dccc0cc082da7d3d8 (diff)
downloadlinux-stericsson-e58dd0de5eadf145895b13451a1fef8ef03946eb.tar.gz
bdi: use refcount_t for reference counting instead atomic_t
refcount_t type and corresponding API should be used instead of atomic_t when the variable is used as a reference counter. This permits avoiding accidental refcounter overflows that might lead to use-after-free situations. Link: http://lkml.kernel.org/r/20180703200141.28415-4-bigeasy@linutronix.de Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Suggested-by: Peter Zijlstra <peterz@infradead.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/backing-dev.c12
1 files changed, 6 insertions, 6 deletions
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 2e5d3df0853d..55a233d75f39 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -438,10 +438,10 @@ retry:
if (new_congested) {
/* !found and storage for new one already allocated, insert */
congested = new_congested;
- new_congested = NULL;
rb_link_node(&congested->rb_node, parent, node);
rb_insert_color(&congested->rb_node, &bdi->cgwb_congested_tree);
- goto found;
+ spin_unlock_irqrestore(&cgwb_lock, flags);
+ return congested;
}
spin_unlock_irqrestore(&cgwb_lock, flags);
@@ -451,13 +451,13 @@ retry:
if (!new_congested)
return NULL;
- atomic_set(&new_congested->refcnt, 0);
+ refcount_set(&new_congested->refcnt, 1);
new_congested->__bdi = bdi;
new_congested->blkcg_id = blkcg_id;
goto retry;
found:
- atomic_inc(&congested->refcnt);
+ refcount_inc(&congested->refcnt);
spin_unlock_irqrestore(&cgwb_lock, flags);
kfree(new_congested);
return congested;
@@ -474,7 +474,7 @@ void wb_congested_put(struct bdi_writeback_congested *congested)
unsigned long flags;
local_irq_save(flags);
- if (!atomic_dec_and_lock(&congested->refcnt, &cgwb_lock)) {
+ if (!refcount_dec_and_lock(&congested->refcnt, &cgwb_lock)) {
local_irq_restore(flags);
return;
}
@@ -804,7 +804,7 @@ static int cgwb_bdi_init(struct backing_dev_info *bdi)
if (!bdi->wb_congested)
return -ENOMEM;
- atomic_set(&bdi->wb_congested->refcnt, 1);
+ refcount_set(&bdi->wb_congested->refcnt, 1);
err = wb_init(&bdi->wb, bdi, 1, GFP_KERNEL);
if (err) {