lib/percpu_ida.c: use _irqsave() instead of local_irq_save() + spin_lock
percpu_ida() decouples disabling interrupts from the locking operations. This breaks some assumptions if the locking operations are replaced like they are under -RT. The same locking can be achieved by avoiding local_irq_save() and using spin_lock_irqsave() instead. percpu_ida_alloc() gains one more preemption point because after unlocking the fastpath and before the pool lock is acquired, the interrupts are briefly enabled. Link: http://lkml.kernel.org/r/20180504153218.7301-1-bigeasy@linutronix.deSigned-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de> Reviewed-by: NAndrew Morton <akpm@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Nicholas Bellinger <nab@linux-iscsi.org> Cc: Shaohua Li <shli@fb.com> Cc: Kent Overstreet <kent.overstreet@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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