[PATCH] scsi: myrs: check return value of dma_alloc_coherent() instead of using dma_mapping_error()

[Peter Kosyh]

dma_alloc_coherent() may leave third parameter uninitialized. So
it is not safe to use dma_mapping_error() without checking return
value of dma_alloc_coherent().

Check the return value of dma_alloc_coherent() to detect
an error.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Signed-off-by: Peter Kosyh <pkosyh@xxxxxxxxx>
---
 drivers/scsi/myrs.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/myrs.c b/drivers/scsi/myrs.c
index 7eb8c39da366..1811c1a6385b 100644
--- a/drivers/scsi/myrs.c
+++ b/drivers/scsi/myrs.c
@@ -498,14 +498,14 @@ static bool myrs_enable_mmio_mbox(struct myrs_hba *cs,
 	/* Temporary dma mapping, used only in the scope of this function */
 	mbox = dma_alloc_coherent(&pdev->dev, sizeof(union myrs_cmd_mbox),
 				  &mbox_addr, GFP_KERNEL);
-	if (dma_mapping_error(&pdev->dev, mbox_addr))
+	if (!mbox)
 		return false;
 
 	/* These are the base addresses for the command memory mailbox array */
 	cs->cmd_mbox_size = MYRS_MAX_CMD_MBOX * sizeof(union myrs_cmd_mbox);
 	cmd_mbox = dma_alloc_coherent(&pdev->dev, cs->cmd_mbox_size,
 				      &cs->cmd_mbox_addr, GFP_KERNEL);
-	if (dma_mapping_error(&pdev->dev, cs->cmd_mbox_addr)) {
+	if (!cmd_mbox) {
 		dev_err(&pdev->dev, "Failed to map command mailbox\n");
 		goto out_free;
 	}
-- 
2.38.1