While allocating for DMA descriptor, GFP_KERNEL flag is being used and
this allocation happens within critical section with spinlock acquired.
This generates a static checker warning.

Use GFP_ATOMIC to prevent sleeping; and since this increases chances of
allocation failure, add handling accordingly.

Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/all/abc223e8-44af-40bb-a0bd-9865b393f435@moroto.mountain/
Signed-off-by: Vijaya Krishna Nivarthi <quic_vnivarth@quicinc.com>
---
 drivers/spi/spi-qcom-qspi.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/spi/spi-qcom-qspi.c b/drivers/spi/spi-qcom-qspi.c
index b995542..b938908 100644
--- a/drivers/spi/spi-qcom-qspi.c
+++ b/drivers/spi/spi-qcom-qspi.c
@@ -308,9 +308,11 @@ static int qcom_qspi_alloc_desc(struct qcom_qspi *ctrl, dma_addr_t dma_ptr,
 	dma_addr_t dma_cmd_desc;
 
 	/* allocate for dma cmd descriptor */
-	virt_cmd_desc = dma_pool_alloc(ctrl->dma_cmd_pool, GFP_KERNEL | __GFP_ZERO, &dma_cmd_desc);
-	if (!virt_cmd_desc)
-		return -ENOMEM;
+	virt_cmd_desc = dma_pool_alloc(ctrl->dma_cmd_pool, GFP_ATOMIC | __GFP_ZERO, &dma_cmd_desc);
+	if (!virt_cmd_desc) {
+		dev_warn_once(ctrl->dev, "Couldn't find memory for descriptor\n");
+		return -EAGAIN;
+	}
 
 	ctrl->virt_cmd_desc[ctrl->n_cmd_desc] = virt_cmd_desc;
 	ctrl->dma_cmd_desc[ctrl->n_cmd_desc] = dma_cmd_desc;
-- 
Qualcomm INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, hosted by the Linux Foundation.

Hi,

On Tue, Jul 25, 2023 at 4:48 AM Vijaya Krishna Nivarthi
<quic_vnivarth@quicinc.com> wrote:
>
> While allocating for DMA descriptor, GFP_KERNEL flag is being used and
> this allocation happens within critical section with spinlock acquired.
> This generates a static checker warning.
>
> Use GFP_ATOMIC to prevent sleeping; and since this increases chances of
> allocation failure, add handling accordingly.
>
> Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
> Closes: https://lore.kernel.org/all/abc223e8-44af-40bb-a0bd-9865b393f435@moroto.mountain/
> Signed-off-by: Vijaya Krishna Nivarthi <quic_vnivarth@quicinc.com>
> ---
>  drivers/spi/spi-qcom-qspi.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)

Fixes: b5762d95607e ("spi: spi-qcom-qspi: Add DMA mode support")
Reviewed-by: Douglas Anderson <dianders@chromium.org>