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authorSascha Hauer <s.hauer@pengutronix.de>2019-12-16 13:53:21 +0300
committerVinod Koul <vkoul@kernel.org>2019-12-26 07:34:18 +0300
commit51fe9cd2bd92d95fc200385187d346e293ceefc9 (patch)
treea246a3539224a5adc2cf2f899ac47f93f407acb8 /drivers/dma/mediatek/mtk-uart-apdma.c
parent5c8aacbbb3b706a024eefc376b1d542d59de5749 (diff)
downloadlinux-51fe9cd2bd92d95fc200385187d346e293ceefc9.tar.xz
dmaengine: virt-dma: Add missing locking
Originally freeing descriptors was split into a locked and an unlocked part. The locked part in vchan_get_all_descriptors() collected all descriptors on a separate list_head. This was done to allow iterating over that new list in vchan_dma_desc_free_list() without a lock held. This became broken in 13bb26ae8850 ("dmaengine: virt-dma: don't always free descriptor upon completion"). With this commit vchan_dma_desc_free_list() no longer exclusively operates on the separate list, but starts to put descriptors which can be reused back on &vc->desc_allocated. This list operation should have been locked, but wasn't. In the mean time drivers started to call vchan_dma_desc_free_list() with their lock held so that we now have the situation that vchan_dma_desc_free_list() is called locked from some drivers and unlocked from others. To clean this up we have to do two things: 1. Add missing locking in vchan_dma_desc_free_list() 2. Make sure drivers call vchan_dma_desc_free_list() unlocked This needs to be done atomically, so in this patch the locking is added and all drivers are fixed. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Reviewed-by: Peter Ujfalusi <peter.ujfalusi@ti.com> Tested-by: Peter Ujfalusi <peter.ujfalusi@ti.com> Reviewed-by: Green Wan <green.wan@sifive.com> Tested-by: Green Wan <green.wan@sifive.com> Link: https://lore.kernel.org/r/20191216105328.15198-3-s.hauer@pengutronix.de Signed-off-by: Vinod Koul <vkoul@kernel.org>
Diffstat (limited to 'drivers/dma/mediatek/mtk-uart-apdma.c')
-rw-r--r--drivers/dma/mediatek/mtk-uart-apdma.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/dma/mediatek/mtk-uart-apdma.c b/drivers/dma/mediatek/mtk-uart-apdma.c
index c20e6bd4e298..29f1223b285a 100644
--- a/drivers/dma/mediatek/mtk-uart-apdma.c
+++ b/drivers/dma/mediatek/mtk-uart-apdma.c
@@ -430,9 +430,10 @@ static int mtk_uart_apdma_terminate_all(struct dma_chan *chan)
spin_lock_irqsave(&c->vc.lock, flags);
vchan_get_all_descriptors(&c->vc, &head);
- vchan_dma_desc_free_list(&c->vc, &head);
spin_unlock_irqrestore(&c->vc.lock, flags);
+ vchan_dma_desc_free_list(&c->vc, &head);
+
return 0;
}