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 13bb26ae88
("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>
This commit is contained in:
Родитель
5c8aacbbb3
Коммит
51fe9cd2bd
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@ -636,14 +636,10 @@ static int dma_chan_terminate_all(struct dma_chan *dchan)
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vchan_get_all_descriptors(&chan->vc, &head);
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/*
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* As vchan_dma_desc_free_list can access to desc_allocated list
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* we need to call it in vc.lock context.
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*/
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vchan_dma_desc_free_list(&chan->vc, &head);
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spin_unlock_irqrestore(&chan->vc.lock, flags);
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vchan_dma_desc_free_list(&chan->vc, &head);
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dev_vdbg(dchan2dev(dchan), "terminated: %s\n", axi_chan_name(chan));
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return 0;
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@ -430,9 +430,10 @@ static int mtk_uart_apdma_terminate_all(struct dma_chan *chan)
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spin_lock_irqsave(&c->vc.lock, flags);
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vchan_get_all_descriptors(&c->vc, &head);
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vchan_dma_desc_free_list(&c->vc, &head);
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spin_unlock_irqrestore(&c->vc.lock, flags);
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vchan_dma_desc_free_list(&c->vc, &head);
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return 0;
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}
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@ -674,10 +674,11 @@ static int owl_dma_terminate_all(struct dma_chan *chan)
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}
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vchan_get_all_descriptors(&vchan->vc, &head);
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vchan_dma_desc_free_list(&vchan->vc, &head);
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spin_unlock_irqrestore(&vchan->vc.lock, flags);
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vchan_dma_desc_free_list(&vchan->vc, &head);
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return 0;
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}
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@ -519,15 +519,6 @@ static void s3c24xx_dma_start_next_txd(struct s3c24xx_dma_chan *s3cchan)
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s3c24xx_dma_start_next_sg(s3cchan, txd);
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}
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static void s3c24xx_dma_free_txd_list(struct s3c24xx_dma_engine *s3cdma,
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struct s3c24xx_dma_chan *s3cchan)
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{
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LIST_HEAD(head);
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vchan_get_all_descriptors(&s3cchan->vc, &head);
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vchan_dma_desc_free_list(&s3cchan->vc, &head);
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}
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/*
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* Try to allocate a physical channel. When successful, assign it to
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* this virtual channel, and initiate the next descriptor. The
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@ -709,8 +700,9 @@ static int s3c24xx_dma_terminate_all(struct dma_chan *chan)
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{
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struct s3c24xx_dma_chan *s3cchan = to_s3c24xx_dma_chan(chan);
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struct s3c24xx_dma_engine *s3cdma = s3cchan->host;
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LIST_HEAD(head);
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unsigned long flags;
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int ret = 0;
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int ret;
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spin_lock_irqsave(&s3cchan->vc.lock, flags);
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@ -734,7 +726,15 @@ static int s3c24xx_dma_terminate_all(struct dma_chan *chan)
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}
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/* Dequeue jobs not yet fired as well */
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s3c24xx_dma_free_txd_list(s3cdma, s3cchan);
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vchan_get_all_descriptors(&s3cchan->vc, &head);
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spin_unlock_irqrestore(&s3cchan->vc.lock, flags);
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vchan_dma_desc_free_list(&s3cchan->vc, &head);
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return 0;
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unlock:
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spin_unlock_irqrestore(&s3cchan->vc.lock, flags);
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@ -155,9 +155,9 @@ static void sf_pdma_free_chan_resources(struct dma_chan *dchan)
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kfree(chan->desc);
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chan->desc = NULL;
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vchan_get_all_descriptors(&chan->vchan, &head);
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vchan_dma_desc_free_list(&chan->vchan, &head);
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sf_pdma_disclaim_chan(chan);
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spin_unlock_irqrestore(&chan->vchan.lock, flags);
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vchan_dma_desc_free_list(&chan->vchan, &head);
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}
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static size_t sf_pdma_desc_residue(struct sf_pdma_chan *chan,
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@ -220,8 +220,8 @@ static int sf_pdma_terminate_all(struct dma_chan *dchan)
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chan->desc = NULL;
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chan->xfer_err = false;
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vchan_get_all_descriptors(&chan->vchan, &head);
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vchan_dma_desc_free_list(&chan->vchan, &head);
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spin_unlock_irqrestore(&chan->vchan.lock, flags);
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vchan_dma_desc_free_list(&chan->vchan, &head);
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return 0;
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}
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@ -885,12 +885,13 @@ static int sun4i_dma_terminate_all(struct dma_chan *chan)
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}
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spin_lock_irqsave(&vchan->vc.lock, flags);
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vchan_dma_desc_free_list(&vchan->vc, &head);
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/* Clear these so the vchan is usable again */
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vchan->processing = NULL;
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vchan->pchan = NULL;
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spin_unlock_irqrestore(&vchan->vc.lock, flags);
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vchan_dma_desc_free_list(&vchan->vc, &head);
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return 0;
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}
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@ -116,7 +116,11 @@ void vchan_dma_desc_free_list(struct virt_dma_chan *vc, struct list_head *head)
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list_for_each_entry_safe(vd, _vd, head, node) {
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if (dmaengine_desc_test_reuse(&vd->tx)) {
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unsigned long flags;
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spin_lock_irqsave(&vc->lock, flags);
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list_move_tail(&vd->node, &vc->desc_allocated);
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spin_unlock_irqrestore(&vc->lock, flags);
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} else {
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dev_dbg(vc->chan.device->dev, "txd %p: freeing\n", vd);
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list_del(&vd->node);
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