From 51fe9cd2bd92d95fc200385187d346e293ceefc9 Mon Sep 17 00:00:00 2001 From: Sascha Hauer Date: Mon, 16 Dec 2019 11:53:21 +0100 Subject: 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 Reviewed-by: Peter Ujfalusi Tested-by: Peter Ujfalusi Reviewed-by: Green Wan Tested-by: Green Wan Link: https://lore.kernel.org/r/20191216105328.15198-3-s.hauer@pengutronix.de Signed-off-by: Vinod Koul --- drivers/dma/sf-pdma/sf-pdma.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/dma/sf-pdma') diff --git a/drivers/dma/sf-pdma/sf-pdma.c b/drivers/dma/sf-pdma/sf-pdma.c index 465256fe8b1f..6d0bec947636 100644 --- a/drivers/dma/sf-pdma/sf-pdma.c +++ b/drivers/dma/sf-pdma/sf-pdma.c @@ -155,9 +155,9 @@ static void sf_pdma_free_chan_resources(struct dma_chan *dchan) kfree(chan->desc); chan->desc = NULL; vchan_get_all_descriptors(&chan->vchan, &head); - vchan_dma_desc_free_list(&chan->vchan, &head); sf_pdma_disclaim_chan(chan); spin_unlock_irqrestore(&chan->vchan.lock, flags); + vchan_dma_desc_free_list(&chan->vchan, &head); } static size_t sf_pdma_desc_residue(struct sf_pdma_chan *chan, @@ -220,8 +220,8 @@ static int sf_pdma_terminate_all(struct dma_chan *dchan) chan->desc = NULL; chan->xfer_err = false; vchan_get_all_descriptors(&chan->vchan, &head); - vchan_dma_desc_free_list(&chan->vchan, &head); spin_unlock_irqrestore(&chan->vchan.lock, flags); + vchan_dma_desc_free_list(&chan->vchan, &head); return 0; } -- cgit