Commit e77e5619 authored by Tudor Ambarus's avatar Tudor Ambarus Committed by Vinod Koul
Browse files

dmaengine: at_xdmac: Fix race over irq_status 



Tasklets run with interrupts enabled, so we need to protect
atchan->irq_status with spin_lock_irq() otherwise the tasklet can be
interrupted by the IRQ that modifies irq_status. Move the dev_dbg that
prints the irq_status in at_xdmac_handle_cyclic() and lower in
at_xdmac_tasklet() where the IRQ is disabled.

Signed-off-by: default avatarTudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20211215110115.191749-13-tudor.ambarus@microchip.com


Signed-off-by: default avatarVinod Koul <vkoul@kernel.org>
parent a61210ca

drivers/dma/at_xdmac.c

+8 −8
Original line number Diff line number Diff line
@@ -1611,6 +1611,8 @@ static void at_xdmac_handle_cyclic(struct at_xdmac_chan *atchan) 
	struct dma_async_tx_descriptor	*txd;



	spin_lock_irq(&atchan->lock);

	dev_dbg(chan2dev(&atchan->chan), "%s: status=0x%08x\n",

		__func__, atchan->irq_status);

	if (list_empty(&atchan->xfers_list)) {

		spin_unlock_irq(&atchan->lock);

		return;
@@ -1623,6 +1625,7 @@ static void at_xdmac_handle_cyclic(struct at_xdmac_chan *atchan) 
		dmaengine_desc_get_callback_invoke(txd, NULL);

}



/* Called with atchan->lock held. */

static void at_xdmac_handle_error(struct at_xdmac_chan *atchan)

{

	struct at_xdmac		*atxdmac = to_at_xdmac(atchan->chan.device);
@@ -1641,8 +1644,6 @@ static void at_xdmac_handle_error(struct at_xdmac_chan *atchan) 
	if (atchan->irq_status & AT_XDMAC_CIS_ROIS)

		dev_err(chan2dev(&atchan->chan), "request overflow error!!!");



	spin_lock_irq(&atchan->lock);



	/* Channel must be disabled first as it's not done automatically */

	at_xdmac_write(atxdmac, AT_XDMAC_GD, atchan->mask);

	while (at_xdmac_read(atxdmac, AT_XDMAC_GS) & atchan->mask)
@@ -1652,8 +1653,6 @@ static void at_xdmac_handle_error(struct at_xdmac_chan *atchan) 
				    struct at_xdmac_desc,

				    xfer_node);



	spin_unlock_irq(&atchan->lock);



	/* Print bad descriptor's details if needed */

	dev_dbg(chan2dev(&atchan->chan),

		"%s: lld: mbr_sa=%pad, mbr_da=%pad, mbr_ubc=0x%08x\n",
@@ -1670,15 +1669,17 @@ static void at_xdmac_tasklet(struct tasklet_struct *t) 
	struct dma_async_tx_descriptor *txd;

	u32			error_mask;



	dev_dbg(chan2dev(&atchan->chan), "%s: status=0x%08x\n",

		__func__, atchan->irq_status);



	if (at_xdmac_chan_is_cyclic(atchan))

		return at_xdmac_handle_cyclic(atchan);



	error_mask = AT_XDMAC_CIS_RBEIS | AT_XDMAC_CIS_WBEIS |

		AT_XDMAC_CIS_ROIS;



	spin_lock_irq(&atchan->lock);



	dev_dbg(chan2dev(&atchan->chan), "%s: status=0x%08x\n",

		__func__, atchan->irq_status);



	if (!(atchan->irq_status & AT_XDMAC_CIS_LIS) &&

	    !(atchan->irq_status & error_mask))

		return;
@@ -1686,7 +1687,6 @@ static void at_xdmac_tasklet(struct tasklet_struct *t) 
	if (atchan->irq_status & error_mask)

		at_xdmac_handle_error(atchan);



	spin_lock_irq(&atchan->lock);

	desc = list_first_entry(&atchan->xfers_list, struct at_xdmac_desc,

				xfer_node);

	dev_vdbg(chan2dev(&atchan->chan), "%s: desc 0x%p\n", __func__, desc);