From: Robin Gong Date: Wed, 14 Jul 2021 10:20:52 +0000 (+0800) Subject: dmaengine: imx-sdma: add terminated list for freed descriptor in worker X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=4e2b10be1f4fe06c9deaaf2c03a05abcff191791;p=linux.git dmaengine: imx-sdma: add terminated list for freed descriptor in worker Add terminated list for keeping descriptor so that it could be freed in worker without any potential involving next descriptor raised up before this descriptor freed, because vchan_get_all_descriptors get all descriptors including the last terminated descriptor and the next descriptor, hence, the next descriptor maybe freed unexpectly when it's done in worker without this patch. https://www.spinics.net/lists/dmaengine/msg23367.html Signed-off-by: Robin Gong Reported-by: Richard Leitner Reviewed-by: Lucas Stach Signed-off-by: Shawn Guo --- diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c index 9ec1edf73879b..cacc725ca5459 100644 --- a/drivers/dma/imx-sdma.c +++ b/drivers/dma/imx-sdma.c @@ -439,6 +439,7 @@ struct sdma_channel { enum dma_status status; struct imx_dma_data data; struct work_struct terminate_worker; + struct list_head terminated; bool is_ram_script; }; @@ -1107,9 +1108,6 @@ static void sdma_channel_terminate_work(struct work_struct *work) { struct sdma_channel *sdmac = container_of(work, struct sdma_channel, terminate_worker); - unsigned long flags; - LIST_HEAD(head); - /* * According to NXP R&D team a delay of one BD SDMA cost time * (maximum is 1ms) should be added after disable of the channel @@ -1118,10 +1116,7 @@ static void sdma_channel_terminate_work(struct work_struct *work) */ usleep_range(1000, 2000); - spin_lock_irqsave(&sdmac->vc.lock, flags); - vchan_get_all_descriptors(&sdmac->vc, &head); - spin_unlock_irqrestore(&sdmac->vc.lock, flags); - vchan_dma_desc_free_list(&sdmac->vc, &head); + vchan_dma_desc_free_list(&sdmac->vc, &sdmac->terminated); } static int sdma_terminate_all(struct dma_chan *chan) @@ -1135,6 +1130,13 @@ static int sdma_terminate_all(struct dma_chan *chan) if (sdmac->desc) { vchan_terminate_vdesc(&sdmac->desc->vd); + /* + * move out current descriptor into terminated list so that + * it could be free in sdma_channel_terminate_work alone + * later without potential involving next descriptor raised + * up before the last descriptor terminated. + */ + vchan_get_all_descriptors(&sdmac->vc, &sdmac->terminated); sdmac->desc = NULL; schedule_work(&sdmac->terminate_worker); } @@ -2130,6 +2132,7 @@ static int sdma_probe(struct platform_device *pdev) sdmac->channel = i; sdmac->vc.desc_free = sdma_desc_free; + INIT_LIST_HEAD(&sdmac->terminated); INIT_WORK(&sdmac->terminate_worker, sdma_channel_terminate_work); /*