diff options
| author | Ming Lei <tom.leiming@gmail.com> | 2014-01-10 12:41:46 +1100 |
|---|---|---|
| committer | Stephen Rothwell <sfr@canb.auug.org.au> | 2014-01-10 12:41:46 +1100 |
| commit | 97e890b9c839c191a500c3a19bfb4539f65c70be (patch) | |
| tree | 16d2ac676f4bbf4e852b8b4a6f95ec667e39e852 /lib | |
| parent | 55cbfd15fd125aad68b9a958749ae2d3c192db9c (diff) | |
lib/percpu_counter.c: disable local irq when updating percpu couter
__percpu_counter_add() may be called in softirq/hardirq handler (such as,
blk_mq_queue_exit() is typically called in hardirq/softirq handler), so we
need to disable local irq when updating the percpu counter, otherwise
counts may be lost.
The patch fixes problem that 'rmmod null_blk' may hang in blk_cleanup_queue()
because of miscounting of request_queue->mq_usage_counter.
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Shaohua Li <shli@fusionio.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Fan Du <fan.du@windriver.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/percpu_counter.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/lib/percpu_counter.c b/lib/percpu_counter.c index 7473ee3b4ee7..2b87bc19b35f 100644 --- a/lib/percpu_counter.c +++ b/lib/percpu_counter.c @@ -75,19 +75,19 @@ EXPORT_SYMBOL(percpu_counter_set); void __percpu_counter_add(struct percpu_counter *fbc, s64 amount, s32 batch) { s64 count; + unsigned long flags; - preempt_disable(); + raw_local_irq_save(flags); count = __this_cpu_read(*fbc->counters) + amount; if (count >= batch || count <= -batch) { - unsigned long flags; - raw_spin_lock_irqsave(&fbc->lock, flags); + raw_spin_lock(&fbc->lock); fbc->count += count; - raw_spin_unlock_irqrestore(&fbc->lock, flags); + raw_spin_unlock(&fbc->lock); __this_cpu_write(*fbc->counters, 0); } else { __this_cpu_write(*fbc->counters, count); } - preempt_enable(); + raw_local_irq_restore(flags); } EXPORT_SYMBOL(__percpu_counter_add); |