From: Kuninori Morimoto kuninori.morimoto.gx@renesas.com
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@jinso.co.jp Signed-off-by: Kuninori Morimoto kuninori.morimoto.gx@renesas.com Tested-by: Keita Kobayashi keita.kobayashi.ym@renesas.com --- drivers/dma/sh/rcar-dmac.c | 55 ++++++++++++++++++++++++++-------------------- 1 file changed, 31 insertions(+), 24 deletions(-)
diff --git a/drivers/dma/sh/rcar-dmac.c b/drivers/dma/sh/rcar-dmac.c index a18d16c..6a5d4b9 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; } @@ -964,12 +969,13 @@ static void rcar_dmac_free_chan_resources(struct dma_chan *chan) struct rcar_dmac *dmac = to_rcar_dmac(chan->device); struct rcar_dmac_desc_page *page, *_page; struct rcar_dmac_desc *desc; + unsigned long flags; LIST_HEAD(list);
/* Protect against ISR */ - spin_lock_irq(&rchan->lock); + spin_lock_irqsave(&rchan->lock, flags); rcar_dmac_chan_halt(rchan); - spin_unlock_irq(&rchan->lock); + spin_unlock_irqrestore(&rchan->lock, flags);
/* Now no new interrupts will occur */
@@ -1351,8 +1357,9 @@ static irqreturn_t rcar_dmac_isr_channel_thread(int irq, void *dev) { struct rcar_dmac_chan *chan = dev; struct rcar_dmac_desc *desc; + unsigned long flags;
- spin_lock_irq(&chan->lock); + spin_lock_irqsave(&chan->lock, flags);
/* For cyclic transfers notify the user after every chunk. */ if (chan->desc.running && chan->desc.running->cyclic) { @@ -1364,9 +1371,9 @@ static irqreturn_t rcar_dmac_isr_channel_thread(int irq, void *dev) callback_param = desc->async_tx.callback_param;
if (callback) { - spin_unlock_irq(&chan->lock); + spin_unlock_irqrestore(&chan->lock, flags); callback(callback_param); - spin_lock_irq(&chan->lock); + spin_lock_irqsave(&chan->lock, flags); } }
@@ -1381,20 +1388,20 @@ static irqreturn_t rcar_dmac_isr_channel_thread(int irq, void *dev) list_del(&desc->node);
if (desc->async_tx.callback) { - spin_unlock_irq(&chan->lock); + spin_unlock_irqrestore(&chan->lock, flags); /* * We own the only reference to this descriptor, we can * safely dereference it without holding the channel * lock. */ desc->async_tx.callback(desc->async_tx.callback_param); - spin_lock_irq(&chan->lock); + spin_lock_irqsave(&chan->lock, flags); }
list_add_tail(&desc->node, &chan->desc.wait); }
- spin_unlock_irq(&chan->lock); + spin_unlock_irqrestore(&chan->lock, flags);
/* Recycle all acked descriptors. */ rcar_dmac_desc_recycle_acked(chan);