[PATCH v2] scsi: qla4xxx: Don't call dma_free_coherent when buf is NULL

[Nathan Chancellor]

When building with -Wsometimes-uninitialized, Clang warns:

drivers/scsi/qla4xxx/ql4_os.c:5915:7: warning: variable 'buf_dma' is
used uninitialized whenever 'if' condition is false
[-Wsometimes-uninitialized]

Don't call dma_free_coherent when buf is NULL, meaning that we never
called dma_alloc_coherent and initialized buf_dma.

Fixes: 2a991c215978 ("[SCSI] qla4xxx: Boot from SAN support for open-iscsi")
Link: https://github.com/ClangBuiltLinux/linux/issues/391
Signed-off-by: Nathan Chancellor <natechancellor@xxxxxxxxx>
---

v1 -> v2:

* Check that buf is not NULL, which matches how dma_free_coherent is
  called in the rest of the tree. This still fixes the warning.

 drivers/scsi/qla4xxx/ql4_os.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/qla4xxx/ql4_os.c b/drivers/scsi/qla4xxx/ql4_os.c
index 16a18d5d856f..9f56dafc3cda 100644
--- a/drivers/scsi/qla4xxx/ql4_os.c
+++ b/drivers/scsi/qla4xxx/ql4_os.c
@@ -5982,7 +5982,8 @@ static int get_fw_boot_info(struct scsi_qla_host *ha, uint16_t ddb_index[])
 			  ddb_index[1]));
 
 exit_boot_info_free:
-	dma_free_coherent(&ha->pdev->dev, size, buf, buf_dma);
+	if (buf)
+		dma_free_coherent(&ha->pdev->dev, size, buf, buf_dma);
 exit_boot_info:
 	ha->pri_ddb_idx = ddb_index[0];
 	ha->sec_ddb_idx = ddb_index[1];
-- 
2.21.0