dmaengine: fsl-edma: check channel acquisition before use

dma_get_slave_channel() can return NULL when acquiring a channel fails,
for example if fsl_edma_alloc_chan_resources() cannot request an IRQ.
fsl_edma3_xlate() dereferences that return value to update privatecnt.

Acquire and check the channel before publishing its source ID and
request parameters. A NULL-only check after the existing source-ID
assignment would leave the failed request marked as in use, causing
fsl_edma_srcid_in_use() to reject a subsequent request for that source.
The channel resource-allocation callback does not consume these request
parameters, so set them only after acquisition succeeds. The existing
scoped mutex release and successful-channel return are preserved.

Detected by static analysis and reviewed with AI-assisted source auditing.

Assisted-by: LLM
Signed-off-by: Slavin Liu <bolin.liu@seu.edu.cn>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20260911060902.94153-1-bolin.liu@seu.edu.cn
Signed-off-by: Vinod Koul <vkoul@kernel.org>

0 files changed, 0 insertions, 0 deletions