From: Kuninori Morimoto Date: Thu, 21 May 2015 03:48:38 +0000 (+0000) Subject: dmaengine: rcar-dmac: fixup spinlock in rcar-dmac X-Git-Tag: v4.9.8~3567^2~79^2^2~23^2 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=d23c9a0a5c237210bccb82a2e9dc0d26e75920ee;p=platform%2Fkernel%2Flinux-rpi3.git dmaengine: rcar-dmac: fixup spinlock in rcar-dmac 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 Signed-off-by: Kuninori Morimoto Tested-by: Keita Kobayashi Acked-by: Vinod Koul Signed-off-by: Mark Brown --- 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; }