linux-kernel - [PATCH 2/4] spi: spi-qcom-qspi: Use GFP_ATOMIC flag while allocating for descriptor

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Message-Id: <1690285689-30233-3-git-send-email-quic_vnivarth@quicinc.com>
Date:   Tue, 25 Jul 2023 17:18:07 +0530
From:   Vijaya Krishna Nivarthi <quic_vnivarth@...cinc.com>
To:     agross@...nel.org, andersson@...nel.org, konrad.dybcio@...aro.org,
        broonie@...nel.org, linux-arm-msm@...r.kernel.org,
        linux-spi@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     quic_msavaliy@...cinc.com, dianders@...omium.org, mka@...omium.org,
        swboyd@...omium.org, quic_vtanuku@...cinc.com,
        dan.carpenter@...aro.org,
        Vijaya Krishna Nivarthi <quic_vnivarth@...cinc.com>
Subject: [PATCH 2/4] spi: spi-qcom-qspi: Use GFP_ATOMIC flag while allocating for descriptor

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@...aro.org>
Closes: https://lore.kernel.org/all/abc223e8-44af-40bb-a0bd-9865b393f435@moroto.mountain/
Signed-off-by: Vijaya Krishna Nivarthi <quic_vnivarth@...cinc.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;
-- 
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