From: Kuninori Morimoto <kuninori.morimoto.gx@xxxxxxxxxxx>
Current rcar-dmac driver is using spin_lock_irq() / spin_unlock_irq()
in some functions. But, some other driver might call DMAEngine API
during interrupt disabled. In such case, rcar-dmac side spin_unlock_irq()
forcefully allows all interrupts. Therefore, other driver receives
unexpected interruption, and its exclusive access control will be broken.
This patch replaces spin_lock_irq() to spin_lock_irqsave(),
and spin_unlock_irq() to spin_unlock_irqrestore().
Reported-by: Cao Minh Hiep <cm-hiep@xxxxxxxxxxx>
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@xxxxxxxxxxx>
Tested-by: Keita Kobayashi <keita.kobayashi.ym@xxxxxxxxxxx>
---
v1 -> v2
- .device_free_chan_resources() doesn't use spin_lock_irqsave()
- rcar_dmac_isr_channel_thread() doesn't use spin_lock_irqsave()
drivers/dma/sh/rcar-dmac.c | 37 +++++++++++++++++++++----------------
1 file changed, 21 insertions(+), 16 deletions(-)
diff --git a/drivers/dma/sh/rcar-dmac.c b/drivers/dma/sh/rcar-dmac.c
index a18d16c..e0302c7 100644
--- a/drivers/dma/sh/rcar-dmac.c
+++ b/drivers/dma/sh/rcar-dmac.c
@@ -465,6 +465,7 @@ static dma_cookie_t rcar_dmac_tx_submit(struct dma_async_tx_descriptor *tx)
static int rcar_dmac_desc_alloc(struct rcar_dmac_chan *chan, gfp_t gfp)
{
struct rcar_dmac_desc_page *page;
+ unsigned long flags;
LIST_HEAD(list);
unsigned int i;
@@ -482,10 +483,10 @@ static int rcar_dmac_desc_alloc(struct rcar_dmac_chan *chan, gfp_t gfp)
list_add_tail(&desc->node, &list);
}
- spin_lock_irq(&chan->lock);
+ spin_lock_irqsave(&chan->lock, flags);
list_splice_tail(&list, &chan->desc.free);
list_add_tail(&page->node, &chan->desc.pages);
- spin_unlock_irq(&chan->lock);
+ spin_unlock_irqrestore(&chan->lock, flags);
return 0;
}
@@ -516,6 +517,7 @@ static void rcar_dmac_desc_put(struct rcar_dmac_chan *chan,
static void rcar_dmac_desc_recycle_acked(struct rcar_dmac_chan *chan)
{
struct rcar_dmac_desc *desc, *_desc;
+ unsigned long flags;
LIST_HEAD(list);
/*
@@ -524,9 +526,9 @@ static void rcar_dmac_desc_recycle_acked(struct rcar_dmac_chan *chan)
* list_for_each_entry_safe, isn't safe if we release the channel lock
* around the rcar_dmac_desc_put() call.
*/
- spin_lock_irq(&chan->lock);
+ spin_lock_irqsave(&chan->lock, flags);
list_splice_init(&chan->desc.wait, &list);
- spin_unlock_irq(&chan->lock);
+ spin_unlock_irqrestore(&chan->lock, flags);
list_for_each_entry_safe(desc, _desc, &list, node) {
if (async_tx_test_ack(&desc->async_tx)) {
@@ -539,9 +541,9 @@ static void rcar_dmac_desc_recycle_acked(struct rcar_dmac_chan *chan)
return;
/* Put the remaining descriptors back in the wait list. */
- spin_lock_irq(&chan->lock);
+ spin_lock_irqsave(&chan->lock, flags);
list_splice(&list, &chan->desc.wait);
- spin_unlock_irq(&chan->lock);
+ spin_unlock_irqrestore(&chan->lock, flags);
}
/*
@@ -556,12 +558,13 @@ static void rcar_dmac_desc_recycle_acked(struct rcar_dmac_chan *chan)
static struct rcar_dmac_desc *rcar_dmac_desc_get(struct rcar_dmac_chan *chan)
{
struct rcar_dmac_desc *desc;
+ unsigned long flags;
int ret;
/* Recycle acked descriptors before attempting allocation. */
rcar_dmac_desc_recycle_acked(chan);
- spin_lock_irq(&chan->lock);
+ spin_lock_irqsave(&chan->lock, flags);
while (list_empty(&chan->desc.free)) {
/*
@@ -570,17 +573,17 @@ static struct rcar_dmac_desc *rcar_dmac_desc_get(struct rcar_dmac_chan *chan)
* allocated descriptors. If the allocation fails return an
* error.
*/
- spin_unlock_irq(&chan->lock);
+ spin_unlock_irqrestore(&chan->lock, flags);
ret = rcar_dmac_desc_alloc(chan, GFP_NOWAIT);
if (ret < 0)
return NULL;
- spin_lock_irq(&chan->lock);
+ spin_lock_irqsave(&chan->lock, flags);
}
desc = list_first_entry(&chan->desc.free, struct rcar_dmac_desc, node);
list_del(&desc->node);
- spin_unlock_irq(&chan->lock);
+ spin_unlock_irqrestore(&chan->lock, flags);
return desc;
}
@@ -593,6 +596,7 @@ static struct rcar_dmac_desc *rcar_dmac_desc_get(struct rcar_dmac_chan *chan)
static int rcar_dmac_xfer_chunk_alloc(struct rcar_dmac_chan *chan, gfp_t gfp)
{
struct rcar_dmac_desc_page *page;
+ unsigned long flags;
LIST_HEAD(list);
unsigned int i;
@@ -606,10 +610,10 @@ static int rcar_dmac_xfer_chunk_alloc(struct rcar_dmac_chan *chan, gfp_t gfp)
list_add_tail(&chunk->node, &list);
}
- spin_lock_irq(&chan->lock);
+ spin_lock_irqsave(&chan->lock, flags);
list_splice_tail(&list, &chan->desc.chunks_free);
list_add_tail(&page->node, &chan->desc.pages);
- spin_unlock_irq(&chan->lock);
+ spin_unlock_irqrestore(&chan->lock, flags);
return 0;
}
@@ -627,9 +631,10 @@ static struct rcar_dmac_xfer_chunk *
rcar_dmac_xfer_chunk_get(struct rcar_dmac_chan *chan)
{
struct rcar_dmac_xfer_chunk *chunk;
+ unsigned long flags;
int ret;
- spin_lock_irq(&chan->lock);
+ spin_lock_irqsave(&chan->lock, flags);
while (list_empty(&chan->desc.chunks_free)) {
/*
@@ -638,18 +643,18 @@ rcar_dmac_xfer_chunk_get(struct rcar_dmac_chan *chan)
* allocated descriptors. If the allocation fails return an
* error.
*/
- spin_unlock_irq(&chan->lock);
+ spin_unlock_irqrestore(&chan->lock, flags);
ret = rcar_dmac_xfer_chunk_alloc(chan, GFP_NOWAIT);
if (ret < 0)
return NULL;
- spin_lock_irq(&chan->lock);
+ spin_lock_irqsave(&chan->lock, flags);
}
chunk = list_first_entry(&chan->desc.chunks_free,
struct rcar_dmac_xfer_chunk, node);
list_del(&chunk->node);
- spin_unlock_irq(&chan->lock);
+ spin_unlock_irqrestore(&chan->lock, flags);
return chunk;
}
--
1.9.1
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