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Ming Lei
74e72f894d
__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 call this_cpu_add()(irq safe helper) to update percpu counter, otherwise counts may be lost. This fixes the problem that 'rmmod null_blk' hangs in blk_cleanup_queue() because of miscounting of request_queue->mq_usage_counter. This patch is the v1 of previous one of "lib/percpu_counter.c: disable local irq when updating percpu couter", and takes Andrew's approach which may be more efficient for ARCHs(x86, s390) that have optimized this_cpu_add(). Signed-off-by: Ming Lei <[email protected]> Cc: Paul Gortmaker <[email protected]> Cc: Shaohua Li <[email protected]> Cc: Jens Axboe <[email protected]> Cc: Fan Du <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>