[PATCH] mlock, mlock2, munlock: Tell the compiler we don't derefernce the pointer

[Sam James]

Xi Ruoyao <xry111@xry111.site> writes:

> Since https://gcc.gnu.org/r11-959, the compiler emits
> -Wmaybe-uninitialized if a const pointer to an uninitialized buffer is
> passed.  Tell the compiler we don't dereference the pointer to remove
> the false alarm.
>

Reviewed-by: Sam James <sam@gentoo.org>

> Link: https://gcc.gnu.org/PR118194
> Signed-off-by: Xi Ruoyao <xry111@xry111.site>
> ---
>
> Tested on x86_64-linux.
>
>  misc/sys/mman.h                            | 6 ++++--
>  sysdeps/unix/sysv/linux/bits/mman-shared.h | 3 ++-
>  2 files changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/misc/sys/mman.h b/misc/sys/mman.h
> index c68a85d140..ae8cee3311 100644
> --- a/misc/sys/mman.h
> +++ b/misc/sys/mman.h
> @@ -100,10 +100,12 @@ extern int posix_madvise (void *__addr, size_t __len, int __advice) __THROW;
>  
>  /* Guarantee all whole pages mapped by the range [ADDR,ADDR+LEN) to
>     be memory resident.  */
> -extern int mlock (const void *__addr, size_t __len) __THROW;
> +extern int mlock (const void *__addr, size_t __len) __THROW
> +    __attr_access ((__none__, 1));
>  
>  /* Unlock whole pages previously mapped by the range [ADDR,ADDR+LEN).  */
> -extern int munlock (const void *__addr, size_t __len) __THROW;
> +extern int munlock (const void *__addr, size_t __len) __THROW
> +    __attr_access ((__none__, 1));
>  
>  /* Cause all currently mapped pages of the process to be memory resident
>     until unlocked by a call to the `munlockall', until the process exits,
> diff --git a/sysdeps/unix/sysv/linux/bits/mman-shared.h b/sysdeps/unix/sysv/linux/bits/mman-shared.h
> index 7a9874204d..d601bd0e8f 100644
> --- a/sysdeps/unix/sysv/linux/bits/mman-shared.h
> +++ b/sysdeps/unix/sysv/linux/bits/mman-shared.h
> @@ -56,7 +56,8 @@ int memfd_create (const char *__name, unsigned int __flags) __THROW;
>  
>  /* Lock pages from ADDR (inclusive) to ADDR + LENGTH (exclusive) into
>     memory.  FLAGS is a combination of the MLOCK_* flags above.  */
> -int mlock2 (const void *__addr, size_t __length, unsigned int __flags) __THROW;
> +int mlock2 (const void *__addr, size_t __length, unsigned int __flags) __THROW
> +    __attr_access ((__none__, 1));
>  
>  /* Allocate a new protection key, with the PKEY_DISABLE_* bits
>     specified in ACCESS_RESTRICTIONS.  The protection key mask for the