[PATCH] Staging: unisys: Change char * array type as static const

[PATCH] Staging: unisys: Change char * array type as static const

[aybuke ozdemir]

This patch fixes "char * array declaration might be better as static
const" checkpatch.pl warning in visorchipset_main.c
After this exchange that can be accessed pointer, without object
derived from the instance but just just read operation can be done in
pointer.

Signed-off-by: aybuke ozdemir <aybuke.147@gmail.com>
---
 drivers/staging/unisys/visorchipset/visorchipset_main.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/staging/unisys/visorchipset/visorchipset_main.c b/drivers/staging/unisys/visorchipset/visorchipset_main.c
index f606ee9..9f25c7f 100644
--- a/drivers/staging/unisys/visorchipset/visorchipset_main.c
+++ b/drivers/staging/unisys/visorchipset/visorchipset_main.c
@@ -1009,7 +1009,7 @@ device_epilog(u32 busNo, u32 devNo, struct spar_segment_state state, u32 cmd,
 
 	struct visorchipset_device_info *pDevInfo =
 		finddevice(&DevInfoList, busNo, devNo);
-	char *envp[] = {
+	static char const *envp[] = {
 		"SPARSP_DIAGPOOL_PAUSED_STATE = 1",
 		NULL
 	};
@@ -1481,7 +1481,7 @@ int
 visorchipset_chipset_selftest(void)
 {
 	char env_selftest[20];
-	char *envp[] = { env_selftest, NULL };
+	static char const *envp[] = { env_selftest, NULL };
 
 	sprintf(env_selftest, "SPARSP_SELFTEST=%d", 1);
 	kobject_uevent_env(&Visorchipset_platform_device.dev.kobj, KOBJ_CHANGE,
@@ -1637,7 +1637,7 @@ parahotplug_request_kickoff(struct parahotplug_request *req)
 	struct controlvm_message_packet *cmd = &req->msg.cmd;
 	char env_cmd[40], env_id[40], env_state[40], env_bus[40], env_dev[40],
 	    env_func[40];
-	char *envp[] = {
+	static char const *envp[] = {
 		env_cmd, env_id, env_state, env_bus, env_dev, env_func, NULL
 	};
 
-- 
1.9.1

Re: [Outreachy kernel] [PATCH] Staging: unisys: Change char * array type as static const

[Arnd Bergmann]

On Tuesday 24 February 2015 00:12:45 aybuke ozdemir wrote:
> @@ -1481,7 +1481,7 @@ int
>  visorchipset_chipset_selftest(void)
>  {
>         char env_selftest[20];
> -       char *envp[] = { env_selftest, NULL };
> +       static char const *envp[] = { env_selftest, NULL };
>  
>         sprintf(env_selftest, "SPARSP_SELFTEST=%d", 1);
>         kobject_uevent_env(&Visorchipset_platform_device.dev.kobj, KOBJ_CHANGE,

Did you mean 'static const char *const envp[]'?

> @@ -1637,7 +1637,7 @@ parahotplug_request_kickoff(struct parahotplug_request *req)
>         struct controlvm_message_packet *cmd = &req->msg.cmd;
>         char env_cmd[40], env_id[40], env_state[40], env_bus[40], env_dev[40],
>             env_func[40];
> -       char *envp[] = {
> +       static char const *envp[] = {
>                 env_cmd, env_id, env_state, env_bus, env_dev, env_func, NULL
>         };

The actual strings are not const here, and the pointers point to objects
on the stack, so what does this change accomplish?

	Arnd

Re: [Outreachy kernel] [PATCH] Staging: unisys: Change char * array type as static const

[aybüke özdemir]

[-- Attachment #1: Type: text/plain, Size: 199 bytes --]

Hi,

I've only changed the pointer, I made it const. I should use it like you
said(static const char *const). Because I can't do const string.

I'll make changes you said and send it again.

Regards

[-- Attachment #2: Type: text/html, Size: 1518 bytes --]

Re: [Outreachy kernel] [PATCH] Staging: unisys: Change char * array type as static const

[Julia Lawall]

> @@ -1481,7 +1481,7 @@ int
>  visorchipset_chipset_selftest(void)
>  {
>  	char env_selftest[20];
> -	char *envp[] = { env_selftest, NULL };
> +	static const char *const envp[] = { env_selftest, NULL };

This appears to be quite incorrect.  env_selftest is an array with no
initialized information at this point.  Adding the const declarations
should make it impossible to put anything in the array.  It seems unlikely
that the compiler would allow this, unless the array is not used at all.
Furthermore, env_selftest is allocated on the stack, whereas a variable
that is declared as static is initialized only once, when the declaration
is first executed.  On subsequent calls to the function, envp will contain
a pointer to an address that now refers to something completely different.

julia



>  	sprintf(env_selftest, "SPARSP_SELFTEST=%d", 1);
>  	kobject_uevent_env(&Visorchipset_platform_device.dev.kobj, KOBJ_CHANGE,
> @@ -1637,7 +1637,7 @@ parahotplug_request_kickoff(struct parahotplug_request *req)
>  	struct controlvm_message_packet *cmd = &req->msg.cmd;
>  	char env_cmd[40], env_id[40], env_state[40], env_bus[40], env_dev[40],
>  	    env_func[40];
> -	char *envp[] = {
> +	static const char *const envp[] = {
>  		env_cmd, env_id, env_state, env_bus, env_dev, env_func, NULL
>  	};
>
> --
> 1.8.3.2
>
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