[PATCH v13 12/12] dmaengine: imx-sdma: add terminated list for freed descriptor in worker
From: Robin Gong <hidden>
Date: 2020-08-31 07:53:02
Also in:
dmaengine, linux-devicetree, linux-spi, lkml
Subsystem:
dma generic offload engine subsystem, the rest · Maintainers:
Vinod Koul, Linus Torvalds
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 <redacted> Reported-by: Richard Leitner <richard.leitner@skidata.com> --- drivers/dma/imx-sdma.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-)
diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c
index 9bb6270..2fa8733 100644
--- a/drivers/dma/imx-sdma.c
+++ b/drivers/dma/imx-sdma.c@@ -381,6 +381,7 @@ 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; };
@@ -1076,9 +1077,6 @@ 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
@@ -1087,10 +1085,7 @@ 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)
@@ -1104,6 +1099,13 @@ 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); }
@@ -2124,6 +2126,7 @@ 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); /*
--
2.7.4
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