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Lockdep reports it too on an Allwinner T113, where the lock > is also taken inside the HARDIRQ-safe vc->lock: > > [ 299.389380] WARNING: possible irq lock inversion dependency detected > [ 299.411196] c7109568 (&sdc->lock){+.-.}-{3:3}, at: sun6i_dma_terminate_all+0x40/0x2c4 > [ 299.419137] but this lock was taken by another, HARDIRQ-safe lock in the past: > [ 299.426398] (&vc->lock){-.-.}-{3:3} > > Use spin_lock_irqsave() in both places, as > sun6i_dma_free_chan_resources() already does. > > Fixes: 555859308723 ("dmaengine: sun6i: Add driver for the Allwinner A31 DMA controller") > Cc: stable@vger.kernel.org > Signed-off-by: Chengfeng Ye > [tien: rebased, added the lockdep report from a T113, Fixes and Cc stable] > Signed-off-by: Nguyen Minh Tien > --- Reviewed-by: Frank Li > I ran into this on a MangoPi MQ-Dual (Allwinner T113-S3): with lockdep > on, stopping dmatest set off the report above in > sun6i_dma_terminate_all(), and a small test module set it off in > sun6i_dma_pause(). While looking for a fix I found Chengfeng's v2 from > 2023. It never got a review and no longer applies, so I rebased it on > dmaengine next and added the lockdep report, a Fixes tag and Cc stable. > Chengfeng, I hope you don't mind me picking it up. > > With it, lockdep stays quiet on both paths on 7.3-rc4, and dmatest on > four channels passes while another channel is paused, resumed and > terminated in a loop. > > v2: https://lore.kernel.org/20230726051727.64088-1-dg573847474@gmail.com > > drivers/dma/sun6i-dma.c | 9 +++++---- > 1 file changed, 5 insertions(+), 4 deletions(-) > > diff --git a/drivers/dma/sun6i-dma.c b/drivers/dma/sun6i-dma.c > index 5ad9d01cf..aee32363c 100644 > --- a/drivers/dma/sun6i-dma.c > +++ b/drivers/dma/sun6i-dma.c > @@ -887,6 +887,7 @@ static int sun6i_dma_pause(struct dma_chan *chan) > struct sun6i_dma_dev *sdev = to_sun6i_dma_dev(chan->device); > struct sun6i_vchan *vchan = to_sun6i_vchan(chan); > struct sun6i_pchan *pchan = vchan->phy; > + unsigned long flags; > > dev_dbg(dmaengine_chan_dev(chan), "vchan %p: pause\n", &vchan->vc); > > @@ -894,9 +895,9 @@ static int sun6i_dma_pause(struct dma_chan *chan) > writel(DMA_CHAN_PAUSE_PAUSE, > pchan->base + DMA_CHAN_PAUSE); > } else { > - spin_lock(&sdev->lock); > + spin_lock_irqsave(&sdev->lock, flags); > list_del_init(&vchan->node); > - spin_unlock(&sdev->lock); > + spin_unlock_irqrestore(&sdev->lock, flags); > } > > return 0; > @@ -935,9 +936,9 @@ static int sun6i_dma_terminate_all(struct dma_chan *chan) > unsigned long flags; > LIST_HEAD(head); > > - spin_lock(&sdev->lock); > + spin_lock_irqsave(&sdev->lock, flags); > list_del_init(&vchan->node); > - spin_unlock(&sdev->lock); > + spin_unlock_irqrestore(&sdev->lock, flags); > > spin_lock_irqsave(&vchan->vc.lock, flags); > > > base-commit: 0a8dda0a15d3926422d286567f945a05328a4ac6 > -- > 2.34.1 >