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authorTudor Ambarus <tudor.ambarus@microchip.com>2020-01-23 14:03:17 +0000
committerVinod Koul <vkoul@kernel.org>2020-02-25 11:27:27 +0530
commit191bd1cad3535a30c2931dc1757e260afe03854b (patch)
tree2c5237475f045f78ac744db8ada45c9be9f46f84 /drivers/dma
parent8592f2c81ebc494017d574fd8b731be44087a2e9 (diff)
downloadlinux-191bd1cad3535a30c2931dc1757e260afe03854b.tar.bz2
dmaengine: at_xdmac: Fix locking in tasklet
Tasklets run with all the interrupts enabled. This means that we should replace all the (already present) spin_lock_irqsave() uses in the tasklet with spin_lock_irq() to protect being interrupted by a IRQ which tries to get the same lock (via calls to device_prep_dma_* for example). spin_lock and spin_lock_bh in tasklets are not enough to protect from IRQs, update these to spin_lock_irq(). at_xdmac_advance_work() can be called with all the interrupts enabled (when called from tasklet), or with interrupts disabled (when called from at_xdmac_issue_pending). Move the locking in the callers to be able to use spin_lock_irq() and spin_lock_irqsave() for these cases. Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com> Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com> Link: https://lore.kernel.org/r/20200123140237.125799-10-tudor.ambarus@microchip.com Signed-off-by: Vinod Koul <vkoul@kernel.org>
Diffstat (limited to 'drivers/dma')
-rw-r--r--drivers/dma/at_xdmac.c23
1 files changed, 12 insertions, 11 deletions
diff --git a/drivers/dma/at_xdmac.c b/drivers/dma/at_xdmac.c
index 31321da69ae6..bb0eaf38b594 100644
--- a/drivers/dma/at_xdmac.c
+++ b/drivers/dma/at_xdmac.c
@@ -1543,9 +1543,6 @@ static void at_xdmac_remove_xfer(struct at_xdmac_chan *atchan,
static void at_xdmac_advance_work(struct at_xdmac_chan *atchan)
{
struct at_xdmac_desc *desc;
- unsigned long flags;
-
- spin_lock_irqsave(&atchan->lock, flags);
/*
* If channel is enabled, do nothing, advance_work will be triggered
@@ -1559,8 +1556,6 @@ static void at_xdmac_advance_work(struct at_xdmac_chan *atchan)
if (!desc->active_xfer)
at_xdmac_start_xfer(atchan, desc);
}
-
- spin_unlock_irqrestore(&atchan->lock, flags);
}
static void at_xdmac_handle_cyclic(struct at_xdmac_chan *atchan)
@@ -1596,7 +1591,7 @@ 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_bh(&atchan->lock);
+ 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);
@@ -1607,7 +1602,7 @@ static void at_xdmac_handle_error(struct at_xdmac_chan *atchan)
struct at_xdmac_desc,
xfer_node);
- spin_unlock_bh(&atchan->lock);
+ spin_unlock_irq(&atchan->lock);
/* Print bad descriptor's details if needed */
dev_dbg(chan2dev(&atchan->chan),
@@ -1640,21 +1635,21 @@ static void at_xdmac_tasklet(unsigned long data)
if (atchan->irq_status & error_mask)
at_xdmac_handle_error(atchan);
- spin_lock(&atchan->lock);
+ 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);
if (!desc->active_xfer) {
dev_err(chan2dev(&atchan->chan), "Xfer not active: exiting");
- spin_unlock(&atchan->lock);
+ spin_unlock_irq(&atchan->lock);
return;
}
txd = &desc->tx_dma_desc;
at_xdmac_remove_xfer(atchan, desc);
- spin_unlock(&atchan->lock);
+ spin_unlock_irq(&atchan->lock);
dma_cookie_complete(txd);
if (txd->flags & DMA_PREP_INTERRUPT)
@@ -1662,7 +1657,9 @@ static void at_xdmac_tasklet(unsigned long data)
dma_run_dependencies(txd);
+ spin_lock_irq(&atchan->lock);
at_xdmac_advance_work(atchan);
+ spin_unlock_irq(&atchan->lock);
}
}
@@ -1723,11 +1720,15 @@ static irqreturn_t at_xdmac_interrupt(int irq, void *dev_id)
static void at_xdmac_issue_pending(struct dma_chan *chan)
{
struct at_xdmac_chan *atchan = to_at_xdmac_chan(chan);
+ unsigned long flags;
dev_dbg(chan2dev(&atchan->chan), "%s\n", __func__);
- if (!at_xdmac_chan_is_cyclic(atchan))
+ if (!at_xdmac_chan_is_cyclic(atchan)) {
+ spin_lock_irqsave(&atchan->lock, flags);
at_xdmac_advance_work(atchan);
+ spin_unlock_irqrestore(&atchan->lock, flags);
+ }
return;
}