linux-kernel - [PATCH] qlogic: qed: fix clang -Wformat warnings

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Message-Id: <20220711232404.2189257-1-justinstitt@google.com>
Date:   Mon, 11 Jul 2022 16:24:04 -0700
From:   Justin Stitt <justinstitt@...gle.com>
To:     Ariel Elior <aelior@...vell.com>,
        Manish Chopra <manishc@...vell.com>,
        "David S . Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>
Cc:     Nathan Chancellor <nathan@...nel.org>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        Tom Rix <trix@...hat.com>, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org, llvm@...ts.linux.dev,
        Justin Stitt <justinstitt@...gle.com>
Subject: [PATCH] qlogic: qed: fix clang -Wformat warnings

When building with Clang we encounter these warnings:
| drivers/net/ethernet/qlogic/qed/qed_dev.c:416:30: error: format
| specifies type 'char' but the argument has type 'u32' (aka 'unsigned
| int') [-Werror,-Wformat] i);
-
| drivers/net/ethernet/qlogic/qed/qed_dev.c:630:13: error: format
| specifies type 'char' but the argument has type 'int' [-Werror,-Wformat]
| p_llh_info->num_ppfid - 1);

For the first warning, `i` is a u32 which is much wider than the format
specifier `%hhd` describes. This results in a loss of bits after 2^7.

The second warning involves implicit integer promotion as the resulting
type of addition cannot be smaller than an int.

example:
``
uint8_t a = 4, b = 7;
int size = sizeof(a + b - 1);
printf("%d\n", size);
// output: 4
```

See more:
(https://wiki.sei.cmu.edu/confluence/display/c/INT02-C.+Understand+integer+conversion+rules)
"Integer types smaller than int are promoted when an operation is
performed on them. If all values of the original type can be represented
as an int, the value of the smaller type is converted to an int;
otherwise, it is converted to an unsigned int."

Link: https://github.com/ClangBuiltLinux/linux/issues/378
Signed-off-by: Justin Stitt <justinstitt@...gle.com>
---
 drivers/net/ethernet/qlogic/qed/qed_dev.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/qlogic/qed/qed_dev.c b/drivers/net/ethernet/qlogic/qed/qed_dev.c
index 672480c9d195..d61cd32ec3b6 100644
--- a/drivers/net/ethernet/qlogic/qed/qed_dev.c
+++ b/drivers/net/ethernet/qlogic/qed/qed_dev.c
@@ -412,7 +412,7 @@ static int qed_llh_alloc(struct qed_dev *cdev)
 			continue;
 
 		p_llh_info->ppfid_array[p_llh_info->num_ppfid] = i;
-		DP_VERBOSE(cdev, QED_MSG_SP, "ppfid_array[%d] = %hhd\n",
+		DP_VERBOSE(cdev, QED_MSG_SP, "ppfid_array[%d] = %u\n",
 			   p_llh_info->num_ppfid, i);
 		p_llh_info->num_ppfid++;
 	}
@@ -626,7 +626,7 @@ static int qed_llh_abs_ppfid(struct qed_dev *cdev, u8 ppfid, u8 *p_abs_ppfid)
 
 	if (ppfid >= p_llh_info->num_ppfid) {
 		DP_NOTICE(cdev,
-			  "ppfid %d is not valid, available indices are 0..%hhd\n",
+			  "ppfid %d is not valid, available indices are 0..%d\n",
 			  ppfid, p_llh_info->num_ppfid - 1);
 		*p_abs_ppfid = 0;
 		return -EINVAL;
-- 
2.37.0.144.g8ac04bfd2-goog