linux-kernel - [PATCH v2 5/6] dmaengine: ti: k3-udma: Use the channel direction in pause/resume functions

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Date:   Fri, 14 Feb 2020 11:14:40 +0200
From:   Peter Ujfalusi <peter.ujfalusi@...com>
To:     <vkoul@...nel.org>
CC:     <dmaengine@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <dan.j.williams@...el.com>, <grygorii.strashko@...com>,
        <vigneshr@...com>
Subject: [PATCH v2 5/6] dmaengine: ti: k3-udma: Use the channel direction in pause/resume functions

It should be possible to pause, resume and check the pause state of a
channel even if we do not have active transfer.

udma_is_chan_paused() can trigger NULL pointer reference in it's current
form when the status is checked while uc->desc is NULL.

Fixes: 25dcb5dd7b7ce ("dmaengine: ti: New driver for K3 UDMA")
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@...com>
---
 drivers/dma/ti/k3-udma.c | 12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)

diff --git a/drivers/dma/ti/k3-udma.c b/drivers/dma/ti/k3-udma.c
index 1dba47c662c4..9b4e1e5fa849 100644
--- a/drivers/dma/ti/k3-udma.c
+++ b/drivers/dma/ti/k3-udma.c
@@ -513,7 +513,7 @@ static bool udma_is_chan_paused(struct udma_chan *uc)
 {
 	u32 val, pause_mask;
 
-	switch (uc->desc->dir) {
+	switch (uc->config.dir) {
 	case DMA_DEV_TO_MEM:
 		val = udma_rchanrt_read(uc->rchan,
 					UDMA_RCHAN_RT_PEER_RT_EN_REG);
@@ -2835,11 +2835,8 @@ static int udma_pause(struct dma_chan *chan)
 {
 	struct udma_chan *uc = to_udma_chan(chan);
 
-	if (!uc->desc)
-		return -EINVAL;
-
 	/* pause the channel */
-	switch (uc->desc->dir) {
+	switch (uc->config.dir) {
 	case DMA_DEV_TO_MEM:
 		udma_rchanrt_update_bits(uc->rchan,
 					 UDMA_RCHAN_RT_PEER_RT_EN_REG,
@@ -2868,11 +2865,8 @@ static int udma_resume(struct dma_chan *chan)
 {
 	struct udma_chan *uc = to_udma_chan(chan);
 
-	if (!uc->desc)
-		return -EINVAL;
-
 	/* resume the channel */
-	switch (uc->desc->dir) {
+	switch (uc->config.dir) {
 	case DMA_DEV_TO_MEM:
 		udma_rchanrt_update_bits(uc->rchan,
 					 UDMA_RCHAN_RT_PEER_RT_EN_REG,
-- 
Peter

Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki