diff options
| author | Sascha Hauer <s.hauer@pengutronix.de> | 2019-12-16 13:53:21 +0300 |
|---|---|---|
| committer | Vinod Koul <vkoul@kernel.org> | 2019-12-26 07:34:18 +0300 |
| commit | 51fe9cd2bd92d95fc200385187d346e293ceefc9 (patch) | |
| tree | a246a3539224a5adc2cf2f899ac47f93f407acb8 /drivers/dma/mediatek/mtk-uart-apdma.c | |
| parent | 5c8aacbbb3b706a024eefc376b1d542d59de5749 (diff) | |
| download | linux-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.c | 3 |
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; } |