Messages in this thread | | | Date | Wed, 31 Jan 2024 09:32:20 +0800 | Subject | Re: [PATCH] dmaengine: virt-dma : fix vchan error on multi-thread | From | Jie Hai <> |
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Hi, Vkoul,
Kindly ping...
Thanks, Jie Hai On 2023/7/20 19:42, Jie Hai wrote: > List desc_allocated was introduced for the case of a transfer > submitted multiple times. But elegating descriptors on the list > causes other problems. > > For example, in the multi-thread scenario, which tasks are > continuously created and submitted by each thread. If one of > the threads calls dmaengine_terminate_all, for dirvers using > vchan_get_all_descriptors, all descriptors will be freed. If > there's another thread submitting a transfer A by > vchan_tx_submit, the following results may be generated: > 1. desc A is freeing -> visit wrong address of node prep/next. > 2. desc A is freed -> visit invalid address of A. > > In the above case, calltrace is generated and the system is > suspended. This can be tested by dmatest. > > This patch removes desc_allocated from vchan_get_all_descriptors, > and add new function 'vchan_get_all_allocated_descs' to get all > descriptors ever allocated. > > And apply vchan_get_all_allocated_descs to free chan resource and > vchan_get_all_descriptors to terminate all transfers, respectively. > This avoids freeing up descriptors in use by other threads. > > Signed-off-by: Jie Hai <haijie1@huawei.com> > --- > drivers/dma/fsl-edma-common.c | 2 +- > drivers/dma/fsl-qdma.c | 2 +- > drivers/dma/sf-pdma/sf-pdma.c | 2 +- > drivers/dma/virt-dma.h | 20 ++++++++++++++++++-- > 4 files changed, 21 insertions(+), 5 deletions(-) > > diff --git a/drivers/dma/fsl-edma-common.c b/drivers/dma/fsl-edma-common.c > index a06a1575a2a5..c6d2e54ab85d 100644 > --- a/drivers/dma/fsl-edma-common.c > +++ b/drivers/dma/fsl-edma-common.c > @@ -674,7 +674,7 @@ void fsl_edma_free_chan_resources(struct dma_chan *chan) > if (edma->drvdata->dmamuxs) > fsl_edma_chan_mux(fsl_chan, 0, false); > fsl_chan->edesc = NULL; > - vchan_get_all_descriptors(&fsl_chan->vchan, &head); > + vchan_get_all_allocated_descs(&fsl_chan->vchan, &head); > fsl_edma_unprep_slave_dma(fsl_chan); > spin_unlock_irqrestore(&fsl_chan->vchan.lock, flags); > > diff --git a/drivers/dma/fsl-qdma.c b/drivers/dma/fsl-qdma.c > index eddb2688f234..5ffd7ba92058 100644 > --- a/drivers/dma/fsl-qdma.c > +++ b/drivers/dma/fsl-qdma.c > @@ -311,7 +311,7 @@ static void fsl_qdma_free_chan_resources(struct dma_chan *chan) > LIST_HEAD(head); > > spin_lock_irqsave(&fsl_chan->vchan.lock, flags); > - vchan_get_all_descriptors(&fsl_chan->vchan, &head); > + vchan_get_all_allocated_descs(&fsl_chan->vchan, &head); > spin_unlock_irqrestore(&fsl_chan->vchan.lock, flags); > > vchan_dma_desc_free_list(&fsl_chan->vchan, &head); > diff --git a/drivers/dma/sf-pdma/sf-pdma.c b/drivers/dma/sf-pdma/sf-pdma.c > index d1c6956af452..f35dc68e1a7c 100644 > --- a/drivers/dma/sf-pdma/sf-pdma.c > +++ b/drivers/dma/sf-pdma/sf-pdma.c > @@ -144,7 +144,7 @@ static void sf_pdma_free_chan_resources(struct dma_chan *dchan) > sf_pdma_disable_request(chan); > kfree(chan->desc); > chan->desc = NULL; > - vchan_get_all_descriptors(&chan->vchan, &head); > + vchan_get_all_allocated_descs(&chan->vchan, &head); > sf_pdma_disclaim_chan(chan); > spin_unlock_irqrestore(&chan->vchan.lock, flags); > vchan_dma_desc_free_list(&chan->vchan, &head); > diff --git a/drivers/dma/virt-dma.h b/drivers/dma/virt-dma.h > index e9f5250fbe4d..65b4f3bdecf7 100644 > --- a/drivers/dma/virt-dma.h > +++ b/drivers/dma/virt-dma.h > @@ -177,13 +177,29 @@ static inline struct virt_dma_desc *vchan_next_desc(struct virt_dma_chan *vc) > static inline void vchan_get_all_descriptors(struct virt_dma_chan *vc, > struct list_head *head) > { > - list_splice_tail_init(&vc->desc_allocated, head); > list_splice_tail_init(&vc->desc_submitted, head); > list_splice_tail_init(&vc->desc_issued, head); > list_splice_tail_init(&vc->desc_completed, head); > list_splice_tail_init(&vc->desc_terminated, head); > } > > +/** > + * vchan_get_all_allocated_descs - obtain all descriptors > + * @vc: virtual channel to get descriptors from > + * @head: list of descriptors found > + * > + * vc.lock must be held by caller > + * > + * Removes all descriptors from internal lists, and provides a list of all > + * descriptors found > + */ > +static inline void vchan_get_all_allocated_descs(struct virt_dma_chan *vc, > + struct list_head *head) > +{ > + list_splice_tail_init(&vc->desc_allocated, head); > + vchan_get_all_descriptors(vc, head); > +} > + > static inline void vchan_free_chan_resources(struct virt_dma_chan *vc) > { > struct virt_dma_desc *vd; > @@ -191,7 +207,7 @@ static inline void vchan_free_chan_resources(struct virt_dma_chan *vc) > LIST_HEAD(head); > > spin_lock_irqsave(&vc->lock, flags); > - vchan_get_all_descriptors(vc, &head); > + vchan_get_all_allocated_descs(vc, &head); > list_for_each_entry(vd, &head, node) > dmaengine_desc_clear_reuse(&vd->tx); > spin_unlock_irqrestore(&vc->lock, flags);
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