linux-kernel - [PATCH] i2c: amd_mp2: handle num is 0 input for i2c_amd

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Date:   Fri,  4 Sep 2020 11:06:47 -0700
From:   trix@...hat.com
To:     syniurge@...il.com, nehal-bakulchandra.shah@....com,
        shyam-sundar.s-k@....com, natechancellor@...il.com,
        ndesaulniers@...gle.com
Cc:     linux-i2c@...r.kernel.org, linux-kernel@...r.kernel.org,
        clang-built-linux@...glegroups.com, Tom Rix <trix@...hat.com>
Subject: [PATCH] i2c: amd_mp2: handle num is 0 input for i2c_amd_xfer

From: Tom Rix <trix@...hat.com>

clang static analyzer reports this problem

i2c-amd-mp2-plat.c:174:9: warning: Branch condition evaluates
  to a garbage value
        return err ? err : num;
               ^~~

err is not initialized, it depends on the being set in the
transfer loop which will not happen if num is 0.  Surveying
other master_xfer() implementations show all handle a 0 num.

Because returning 0 is expected, initialize err to 0.

Signed-off-by: Tom Rix <trix@...hat.com>
---
 drivers/i2c/busses/i2c-amd-mp2-plat.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/i2c/busses/i2c-amd-mp2-plat.c b/drivers/i2c/busses/i2c-amd-mp2-plat.c
index 17df9e8845b6..506433bc0ff2 100644
--- a/drivers/i2c/busses/i2c-amd-mp2-plat.c
+++ b/drivers/i2c/busses/i2c-amd-mp2-plat.c
@@ -155,7 +155,7 @@ static int i2c_amd_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
 	struct amd_i2c_dev *i2c_dev = i2c_get_adapdata(adap);
 	int i;
 	struct i2c_msg *pmsg;
-	int err;
+	int err = 0;
 
 	/* the adapter might have been deleted while waiting for the bus lock */
 	if (unlikely(!i2c_dev->common.mp2_dev))
-- 
2.18.1