[PATCH] net/mana: avoid the use of variable length array

[PATCH] net/mana: avoid the use of variable length array

[longli]

From: Long Li <longli@microsoft.com>

The pathname can be defined as name[MAX_PATH]. This makes the driver
compilable using MSVC.

Signed-off-by: Long Li <longli@microsoft.com>
---
 drivers/net/mana/mana.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/drivers/net/mana/mana.c b/drivers/net/mana/mana.c
index c37c4e3444..d12dff6ce1 100644
--- a/drivers/net/mana/mana.c
+++ b/drivers/net/mana/mana.c
@@ -36,11 +36,8 @@ static rte_spinlock_t mana_shared_data_lock = RTE_SPINLOCK_INITIALIZER;
 
 /* Allocate a buffer on the stack and fill it with a printf format string. */
 #define MANA_MKSTR(name, ...) \
-	int mkstr_size_##name = snprintf(NULL, 0, "" __VA_ARGS__); \
-	char name[mkstr_size_##name + 1]; \
-	\
-	memset(name, 0, mkstr_size_##name + 1); \
-	snprintf(name, sizeof(name), "" __VA_ARGS__)
+	char name[PATH_MAX]; \
+	snprintf(name, PATH_MAX, "" __VA_ARGS__)
 
 int mana_logtype_driver;
 int mana_logtype_init;
-- 
2.34.1

RE: [PATCH] net/mana: avoid the use of variable length array

[Morten Brørup]

> From: longli@linuxonhyperv.com [mailto:longli@linuxonhyperv.com]
> Sent: Wednesday, 5 March 2025 01.38
> 
> From: Long Li <longli@microsoft.com>
> 
> The pathname can be defined as name[MAX_PATH]. This makes the driver
> compilable using MSVC.

The name is PATH_MAX, not MAX_PATH. It's correct in the code.

> 
> Signed-off-by: Long Li <longli@microsoft.com>
> ---
>  drivers/net/mana/mana.c | 7 ++-----
>  1 file changed, 2 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/net/mana/mana.c b/drivers/net/mana/mana.c
> index c37c4e3444..d12dff6ce1 100644
> --- a/drivers/net/mana/mana.c
> +++ b/drivers/net/mana/mana.c
> @@ -36,11 +36,8 @@ static rte_spinlock_t mana_shared_data_lock =
> RTE_SPINLOCK_INITIALIZER;
> 
>  /* Allocate a buffer on the stack and fill it with a printf format
> string. */
>  #define MANA_MKSTR(name, ...) \

The macro is no longer generic, but tied to a path name, so the macro's name and description should be updated accordingly. E.g.:

/* Allocate a path name buffer on the stack and fill it with a printf format string. */
#define MANA_MKPATHSTR(name, ...) \

Don't forget search-replace for uses of the macro. (It's being used 6 times in this file.)

> -	int mkstr_size_##name = snprintf(NULL, 0, "" __VA_ARGS__); \
> -	char name[mkstr_size_##name + 1]; \
> -	\
> -	memset(name, 0, mkstr_size_##name + 1); \
> -	snprintf(name, sizeof(name), "" __VA_ARGS__)
> +	char name[PATH_MAX]; \
> +	snprintf(name, PATH_MAX, "" __VA_ARGS__)
> 
>  int mana_logtype_driver;
>  int mana_logtype_init;
> --
> 2.34.1

With suggested changes,
Acked-by: Morten Brørup <mb@smartsharesystems.com>