dmaengine: idxd: use spin_lock_irqsave before wait_event_lock_irq
[ Upstream commit c0409dd3 ] In idxd_cmd_exec(), wait_event_lock_irq() explicitly calls spin_unlock_irq()/spin_lock_irq(). If the interrupt is on before entering wait_event_lock_irq(), it will become off status after wait_event_lock_irq() is called. Later, wait_for_completion() may go to sleep but irq is disabled. The scenario is warned in might_sleep(). Fix it by using spin_lock_irqsave() instead of the primitive spin_lock() to save the irq status before entering wait_event_lock_irq() and using spin_unlock_irqrestore() instead of the primitive spin_unlock() to restore the irq status before entering wait_for_completion(). Before the change: idxd_cmd_exec() { interrupt is on spin_lock() // interrupt is on wait_event_lock_irq() spin_unlock_irq() // interrupt is enabled ... spin_lock_irq() // interrupt is disabled spin_unlock() // interrupt is still disabled wait_for_completion() // report "BUG: sleeping function // called from invalid context... // in_atomic() irqs_disabled()" } After applying spin_lock_irqsave(): idxd_cmd_exec() { interrupt is on spin_lock_irqsave() // save the on state // interrupt is disabled wait_event_lock_irq() spin_unlock_irq() // interrupt is enabled ... spin_lock_irq() // interrupt is disabled spin_unlock_irqrestore() // interrupt is restored to on wait_for_completion() // No Call trace } Fixes: f9f4082d ("dmaengine: idxd: remove interrupt disable for cmd_lock") Signed-off-by: Rex Zhang <rex.zhang@intel.com> Signed-off-by: Lijun Pan <lijun.pan@intel.com> Reviewed-by: Dave Jiang <dave.jiang@intel.com> Reviewed-by: Fenghua Yu <fenghua.yu@intel.com> Link: https://lore.kernel.org/r/20230916060619.3744220-1-rex.zhang@intel.com Signed-off-by: Vinod Koul <vkoul@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
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