[PATCH v3 2/2] dmaengine: ti: k3-udma: Set rchan/tchan to NULL if a channel request fail
From: Kishon Vijay Abraham I <hidden>
Date: 2021-10-29 15:13:03
Also in:
lkml
Subsystem:
dma generic offload engine subsystem, texas instruments dma drivers, the rest · Maintainers:
Vinod Koul, Peter Ujfalusi, Linus Torvalds
udma_get_*() checks if rchan/tchan/rflow is already allocated by checking if it has a NON NULL value. For the error cases, rchan/tchan/rflow will have error value and udma_get_*() considers this as already allocated (PASS) since the error values are NON NULL. This results in NULL pointer dereference error while de-referencing rchan/tchan/rflow. Reset the value of rchan/tchan/rflow to NULL if a channel request fails. Signed-off-by: Kishon Vijay Abraham I <redacted> --- drivers/dma/ti/k3-udma.c | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-)
diff --git a/drivers/dma/ti/k3-udma.c b/drivers/dma/ti/k3-udma.c
index 14ae28830871..041d8e32d630 100644
--- a/drivers/dma/ti/k3-udma.c
+++ b/drivers/dma/ti/k3-udma.c@@ -1380,6 +1380,7 @@ static int bcdma_get_bchan(struct udma_chan *uc) static int udma_get_tchan(struct udma_chan *uc) { struct udma_dev *ud = uc->ud; + int ret; if (uc->tchan) { dev_dbg(ud->dev, "chan%d: already have tchan%d allocated\n",
@@ -1394,8 +1395,11 @@ static int udma_get_tchan(struct udma_chan *uc) */ uc->tchan = __udma_reserve_tchan(ud, uc->config.channel_tpl, uc->config.mapped_channel_id); - if (IS_ERR(uc->tchan)) - return PTR_ERR(uc->tchan); + if (IS_ERR(uc->tchan)) { + ret = PTR_ERR(uc->tchan); + uc->tchan = NULL; + return ret; + } if (ud->tflow_cnt) { int tflow_id;
@@ -1425,6 +1429,7 @@ static int udma_get_tchan(struct udma_chan *uc) static int udma_get_rchan(struct udma_chan *uc) { struct udma_dev *ud = uc->ud; + int ret; if (uc->rchan) { dev_dbg(ud->dev, "chan%d: already have rchan%d allocated\n",
@@ -1439,8 +1444,13 @@ static int udma_get_rchan(struct udma_chan *uc) */ uc->rchan = __udma_reserve_rchan(ud, uc->config.channel_tpl, uc->config.mapped_channel_id); + if (IS_ERR(uc->rchan)) { + ret = PTR_ERR(uc->rchan); + uc->rchan = NULL; + return ret; + } - return PTR_ERR_OR_ZERO(uc->rchan); + return 0; } static int udma_get_chan_pair(struct udma_chan *uc)
@@ -1494,6 +1504,7 @@ static int udma_get_chan_pair(struct udma_chan *uc) static int udma_get_rflow(struct udma_chan *uc, int flow_id) { struct udma_dev *ud = uc->ud; + int ret; if (!uc->rchan) { dev_err(ud->dev, "chan%d: does not have rchan??\n", uc->id);
@@ -1507,8 +1518,13 @@ static int udma_get_rflow(struct udma_chan *uc, int flow_id) } uc->rflow = __udma_get_rflow(ud, flow_id); + if (IS_ERR(uc->rflow)) { + ret = PTR_ERR(uc->rflow); + uc->rflow = NULL; + return ret; + } - return PTR_ERR_OR_ZERO(uc->rflow); + return 0; } static void bcdma_put_bchan(struct udma_chan *uc)
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2.17.1