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authorKuninori Morimoto <kuninori.morimoto.gx@renesas.com>2016-05-30 03:41:48 +0300
committerVinod Koul <vinod.koul@intel.com>2016-05-30 06:42:00 +0300
commit3565fe53334cd3f0d59ff5db0872de9370775a19 (patch)
tree45e7a4b53ca4017f657a4feee539f93e8969d7f6 /drivers/dma/sh
parent1a695a905c18548062509178b98bc91e67510864 (diff)
downloadlinux-3565fe53334cd3f0d59ff5db0872de9370775a19.tar.xz
dmaengine: rcar-dmac: use list_add() on rcar_dmac_desc_put()
For each descriptor, in addition to the memory used by the descriptors structure itself, the driver allocates a list of chunks as well as a buffer for hardware descriptors. Descriptors themselves are preallocated, and allocation of the chunks and buffer is performed the first time the descriptor is used. The memory isn't freed when the transfer is completed, as the chunks and buffer will be needed again when the descriptor is reused internally, so the driver keeps the memory around. If only a few descriptors are used concurrently, the current list_add_tail() implementation will result in all preallocated descriptors being used before going back to the first one, and will thus allocate chunks and a buffer for all preallocated descriptors. Using list_add() will put the complete descriptor at the head of the list of available descriptors, so the next transfer will be more likely to reuse a descriptor that already has associated memory instead of one that has never been used before. Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Diffstat (limited to 'drivers/dma/sh')
-rw-r--r--drivers/dma/sh/rcar-dmac.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/dma/sh/rcar-dmac.c b/drivers/dma/sh/rcar-dmac.c
index dfb17926297b..433e98260414 100644
--- a/drivers/dma/sh/rcar-dmac.c
+++ b/drivers/dma/sh/rcar-dmac.c
@@ -510,7 +510,7 @@ static void rcar_dmac_desc_put(struct rcar_dmac_chan *chan,
spin_lock_irqsave(&chan->lock, flags);
list_splice_tail_init(&desc->chunks, &chan->desc.chunks_free);
- list_add_tail(&desc->node, &chan->desc.free);
+ list_add(&desc->node, &chan->desc.free);
spin_unlock_irqrestore(&chan->lock, flags);
}