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dmaengine: at_xdmac: Fix race over irq_status

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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: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20211215110115.191749-13-tudor.ambarus@microchip.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
This commit is contained in:
Tudor Ambarus 2021-12-15 13:01:15 +02:00 committed by Vinod Koul
parent a61210cae8
commit e77e561925
1 changed files with 8 additions and 8 deletions
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16
drivers/dma/at_xdmac.c
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@ -1611,6 +1611,8 @@ static void at_xdmac_handle_cyclic(struct at_xdmac_chan *atchan)
struct dma_async_tx_descriptor *txd; struct dma_async_tx_descriptor *txd;
spin_lock_irq(&atchan->lock); 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)) { if (list_empty(&atchan->xfers_list)) {
spin_unlock_irq(&atchan->lock); spin_unlock_irq(&atchan->lock);
return; return;
@ -1623,6 +1625,7 @@ static void at_xdmac_handle_cyclic(struct at_xdmac_chan *atchan)
dmaengine_desc_get_callback_invoke(txd, NULL); dmaengine_desc_get_callback_invoke(txd, NULL);
} }
/* Called with atchan->lock held. */
static void at_xdmac_handle_error(struct at_xdmac_chan *atchan) static void at_xdmac_handle_error(struct at_xdmac_chan *atchan)
{ {
struct at_xdmac *atxdmac = to_at_xdmac(atchan->chan.device); 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) if (atchan->irq_status & AT_XDMAC_CIS_ROIS)
dev_err(chan2dev(&atchan->chan), "request overflow error!!!"); dev_err(chan2dev(&atchan->chan), "request overflow error!!!");
spin_lock_irq(&atchan->lock);
/* Channel must be disabled first as it's not done automatically */ /* Channel must be disabled first as it's not done automatically */
at_xdmac_write(atxdmac, AT_XDMAC_GD, atchan->mask); at_xdmac_write(atxdmac, AT_XDMAC_GD, atchan->mask);
while (at_xdmac_read(atxdmac, AT_XDMAC_GS) & 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, struct at_xdmac_desc,
xfer_node); xfer_node);
spin_unlock_irq(&atchan->lock);
/* Print bad descriptor's details if needed */ /* Print bad descriptor's details if needed */
dev_dbg(chan2dev(&atchan->chan), dev_dbg(chan2dev(&atchan->chan),
"%s: lld: mbr_sa=%pad, mbr_da=%pad, mbr_ubc=0x%08x\n", "%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; struct dma_async_tx_descriptor *txd;
u32 error_mask; u32 error_mask;
dev_dbg(chan2dev(&atchan->chan), "%s: status=0x%08x\n",
__func__, atchan->irq_status);
if (at_xdmac_chan_is_cyclic(atchan)) if (at_xdmac_chan_is_cyclic(atchan))
return at_xdmac_handle_cyclic(atchan); return at_xdmac_handle_cyclic(atchan);
error_mask = AT_XDMAC_CIS_RBEIS | AT_XDMAC_CIS_WBEIS | error_mask = AT_XDMAC_CIS_RBEIS | AT_XDMAC_CIS_WBEIS |
AT_XDMAC_CIS_ROIS; 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) && if (!(atchan->irq_status & AT_XDMAC_CIS_LIS) &&
!(atchan->irq_status & error_mask)) !(atchan->irq_status & error_mask))
return; return;
@ -1686,7 +1687,6 @@ static void at_xdmac_tasklet(struct tasklet_struct *t)
if (atchan->irq_status & error_mask) if (atchan->irq_status & error_mask)
at_xdmac_handle_error(atchan); at_xdmac_handle_error(atchan);
spin_lock_irq(&atchan->lock);
desc = list_first_entry(&atchan->xfers_list, struct at_xdmac_desc, desc = list_first_entry(&atchan->xfers_list, struct at_xdmac_desc,
xfer_node); xfer_node);
dev_vdbg(chan2dev(&atchan->chan), "%s: desc 0x%p\n", __func__, desc); dev_vdbg(chan2dev(&atchan->chan), "%s: desc 0x%p\n", __func__, desc);