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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>
This commit is contained in:
Tudor Ambarus 2020-01-23 14:03:17 +00:00 committed by Vinod Koul
parent 8592f2c81e
commit 191bd1cad3
1 changed files with 12 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

23
drivers/dma/at_xdmac.c
View File

@ -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) static void at_xdmac_advance_work(struct at_xdmac_chan *atchan)
{ {
struct at_xdmac_desc *desc; 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 * 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) if (!desc->active_xfer)
at_xdmac_start_xfer(atchan, desc); at_xdmac_start_xfer(atchan, desc);
} }
spin_unlock_irqrestore(&atchan->lock, flags);
} }
static void at_xdmac_handle_cyclic(struct at_xdmac_chan *atchan) 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) 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_bh(&atchan->lock); 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);
@ -1607,7 +1602,7 @@ 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_bh(&atchan->lock); 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),
@ -1640,21 +1635,21 @@ static void at_xdmac_tasklet(unsigned long data)
if (atchan->irq_status & error_mask) if (atchan->irq_status & error_mask)
at_xdmac_handle_error(atchan); at_xdmac_handle_error(atchan);
spin_lock(&atchan->lock); spin_lock_irq(&atchan->lock);
desc = list_first_entry(&atchan->xfers_list, desc = list_first_entry(&atchan->xfers_list,
struct at_xdmac_desc, 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);
if (!desc->active_xfer) { if (!desc->active_xfer) {
dev_err(chan2dev(&atchan->chan), "Xfer not active: exiting"); dev_err(chan2dev(&atchan->chan), "Xfer not active: exiting");
spin_unlock(&atchan->lock); spin_unlock_irq(&atchan->lock);
return; return;
} }
txd = &desc->tx_dma_desc; txd = &desc->tx_dma_desc;
at_xdmac_remove_xfer(atchan, desc); at_xdmac_remove_xfer(atchan, desc);
spin_unlock(&atchan->lock); spin_unlock_irq(&atchan->lock);
dma_cookie_complete(txd); dma_cookie_complete(txd);
if (txd->flags & DMA_PREP_INTERRUPT) if (txd->flags & DMA_PREP_INTERRUPT)
@ -1662,7 +1657,9 @@ static void at_xdmac_tasklet(unsigned long data)
dma_run_dependencies(txd); dma_run_dependencies(txd);
spin_lock_irq(&atchan->lock);
at_xdmac_advance_work(atchan); 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) static void at_xdmac_issue_pending(struct dma_chan *chan)
{ {
struct at_xdmac_chan *atchan = to_at_xdmac_chan(chan); struct at_xdmac_chan *atchan = to_at_xdmac_chan(chan);
unsigned long flags;
dev_dbg(chan2dev(&atchan->chan), "%s\n", __func__); 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); at_xdmac_advance_work(atchan);
spin_unlock_irqrestore(&atchan->lock, flags);
}
return; return;
} }