Hi, I get a lockdep warning in the zynqmp dma driver and I am not entirely sure how to fix it. The code in drivers/dma/xilinx/zynqmp_dma.c looks as follows: 604 static void zynqmp_dma_chan_desc_cleanup(struct zynqmp_dma_chan *chan) 605 { [...] 612 callback = desc->async_tx.callback; 613 callback_param = desc->async_tx.callback_param; 614 if (callback) { 615 spin_unlock(&chan->lock); 616 callback(callback_param); 617 spin_lock(&chan->lock); 618 } [...] 626 } [...] 747 static void zynqmp_dma_do_tasklet(struct tasklet_struct *t) 748 { [...] 753 spin_lock_irqsave(&chan->lock, irqflags); [...] 763 while (count) { 764 zynqmp_dma_complete_descriptor(chan); 765 zynqmp_dma_chan_desc_cleanup(chan); 766 count--; 767 } [...] 773 spin_unlock_irqrestore(&chan->lock, irqflags); 774 } Lockdep reports that in line 617 spin_lock() is called from a non-hardirq context, while the same lock is used from a hardirq context. During runtime, the sequence is as follows: line 753: acquire lock and disable interrupts line 615: release lock without enabling interrupts line 617: re-acquire lock with still disabled interrupts line 773: released lock and re-enable interrupts Is this a false positive of lockdep, because it does not know that the irqs are still disabled in line 617? Is it actually OK to leave interrupts disabled over a spin_unlock() -> spin_lock() sequence or is this a problem? Additionally, the lock is held for the entire tasklet that handles the finished dma transfer. This is conflict to the rule that spin locks should be held only for a short time. Is it necessary to hold the lock that long? I understand that the lock is only used to protect the descriptor lists and it would be better to only get the lock when descriptors are moved between lists. Any guidance would be helpful. Michael -- Pengutronix e.K. | Michael Tretter | Steuerwalder Str. 21 | https://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |