linux-kernel - [PATCH] hwrng: optee: Initialize some structs using memset instead of braces

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Message-Id: <20190219032240.22935-1-natechancellor@gmail.com>
Date:   Mon, 18 Feb 2019 20:22:40 -0700
From:   Nathan Chancellor <natechancellor@...il.com>
To:     Sumit Garg <sumit.garg@...aro.org>,
        Jens Wiklander <jens.wiklander@...aro.org>
Cc:     Matt Mackall <mpm@...enic.com>,
        Herbert Xu <herbert@...dor.apana.org.au>,
        linux-crypto@...r.kernel.org, linux-kernel@...r.kernel.org,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        Daniel Thompson <daniel.thompson@...aro.org>,
        Nathan Chancellor <natechancellor@...il.com>
Subject: [PATCH] hwrng: optee: Initialize some structs using memset instead of braces

Clang warns:

drivers/char/hw_random/optee-rng.c:80:31: warning: suggest braces around
initialization of subobject [-Wmissing-braces]
        struct tee_param param[4] = {0};
                                     ^
                                     {}
drivers/char/hw_random/optee-rng.c:177:31: warning: suggest braces
around initialization of subobject [-Wmissing-braces]
        struct tee_param param[4] = {0};
                                     ^
                                     {}
drivers/char/hw_random/optee-rng.c:212:48: warning: suggest braces
around initialization of subobject [-Wmissing-braces]
        struct tee_ioctl_open_session_arg sess_arg = {0};
                                                      ^
                                                      {}
3 warnings generated.

One way to fix these warnings is to add additional braces like Clang
suggests; however, there has been a bit of push back from some
maintainers, who just prefer memset as it is unambiguous, doesn't
depend on a particular compiler version, and properly initializes all
subobjects [1][2]. Do that here so there are no more warnings.

[1]: https://lore.kernel.org/lkml/022e41c0-8465-dc7a-a45c-64187ecd9684@amd.com/
[2]: https://lore.kernel.org/lkml/20181128.215241.702406654469517539.davem@davemloft.net/

Fixes: 5fe8b1cc6a03 ("hwrng: add OP-TEE based rng driver")
Link: https://github.com/ClangBuiltLinux/linux/issues/369
Signed-off-by: Nathan Chancellor <natechancellor@...il.com>
---
 drivers/char/hw_random/optee-rng.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/drivers/char/hw_random/optee-rng.c b/drivers/char/hw_random/optee-rng.c
index 2b9fc8ac5500..46f4bcd28c41 100644
--- a/drivers/char/hw_random/optee-rng.c
+++ b/drivers/char/hw_random/optee-rng.c
@@ -76,8 +76,11 @@ static size_t get_optee_rng_data(struct optee_rng_private *pvt_data,
 	u32 ret = 0;
 	u8 *rng_data = NULL;
 	size_t rng_size = 0;
-	struct tee_ioctl_invoke_arg inv_arg = {0};
-	struct tee_param param[4] = {0};
+	struct tee_ioctl_invoke_arg inv_arg;
+	struct tee_param param[4];
+
+	memset(&inv_arg, 0, sizeof(inv_arg));
+	memset(&param, 0, sizeof(param));
 
 	/* Invoke TA_CMD_GET_ENTROPY function of Trusted App */
 	inv_arg.func = TA_CMD_GET_ENTROPY;
@@ -173,8 +176,11 @@ static struct optee_rng_private pvt_data = {
 static int get_optee_rng_info(struct device *dev)
 {
 	u32 ret = 0;
-	struct tee_ioctl_invoke_arg inv_arg = {0};
-	struct tee_param param[4] = {0};
+	struct tee_ioctl_invoke_arg inv_arg;
+	struct tee_param param[4];
+
+	memset(&inv_arg, 0, sizeof(inv_arg));
+	memset(&param, 0, sizeof(param));
 
 	/* Invoke TA_CMD_GET_RNG_INFO function of Trusted App */
 	inv_arg.func = TA_CMD_GET_RNG_INFO;
@@ -209,7 +215,9 @@ static int optee_rng_probe(struct device *dev)
 {
 	struct tee_client_device *rng_device = to_tee_client_device(dev);
 	int ret = 0, err = -ENODEV;
-	struct tee_ioctl_open_session_arg sess_arg = {0};
+	struct tee_ioctl_open_session_arg sess_arg;
+
+	memset(&sess_arg, 0, sizeof(sess_arg));
 
 	/* Open context with TEE driver */
 	pvt_data.ctx = tee_client_open_context(NULL, optee_ctx_match, NULL,
-- 
2.21.0.rc1