[PATCH] futex: remove unused empty compat_exit_robust_list()

[PATCH] futex: remove unused empty compat_exit_robust_list()

[Lukas Bulwahn]

Commit ba31c1a48538 ("futex: Move futex exit handling into futex code")
introduced compat_exit_robust_list() with a full-fledged implementation for
CONFIG_COMPAT, and an empty-body function for !CONFIG_COMPAT.
However, compat_exit_robust_list() is only used in futex_mm_release() under
ifdef CONFIG_COMPAT.

Hence for !CONFIG_COMPAT, make CC=clang W=1 warns:

  kernel/futex.c:314:20:
    warning: unused function 'compat_exit_robust_list' [-Wunused-function]

There is no need to declare the unused empty function for !CONFIG_COMPAT.
Simply, remove it to address the -Wunused-function warning.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
---
applies cleanly on current master and next-20201113

Thomas, please pick this minor non-urgent clean-up patch.

 kernel/futex.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/kernel/futex.c b/kernel/futex.c
index 00259c7e288e..c47d1015d759 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -310,8 +310,6 @@ static inline bool should_fail_futex(bool fshared)
 
 #ifdef CONFIG_COMPAT
 static void compat_exit_robust_list(struct task_struct *curr);
-#else
-static inline void compat_exit_robust_list(struct task_struct *curr) { }
 #endif
 
 /*
-- 
2.17.1

Re: [PATCH] futex: remove unused empty compat_exit_robust_list()

[Nathan Chancellor]

On Fri, Nov 13, 2020 at 06:20:12PM +0100, Lukas Bulwahn wrote:
> Commit ba31c1a48538 ("futex: Move futex exit handling into futex code")
> introduced compat_exit_robust_list() with a full-fledged implementation for
> CONFIG_COMPAT, and an empty-body function for !CONFIG_COMPAT.
> However, compat_exit_robust_list() is only used in futex_mm_release() under
> ifdef CONFIG_COMPAT.
> 
> Hence for !CONFIG_COMPAT, make CC=clang W=1 warns:
> 
>   kernel/futex.c:314:20:
>     warning: unused function 'compat_exit_robust_list' [-Wunused-function]
> 
> There is no need to declare the unused empty function for !CONFIG_COMPAT.
> Simply, remove it to address the -Wunused-function warning.
> 
> Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>

Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>

> ---
> applies cleanly on current master and next-20201113
> 
> Thomas, please pick this minor non-urgent clean-up patch.
> 
>  kernel/futex.c | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/kernel/futex.c b/kernel/futex.c
> index 00259c7e288e..c47d1015d759 100644
> --- a/kernel/futex.c
> +++ b/kernel/futex.c
> @@ -310,8 +310,6 @@ static inline bool should_fail_futex(bool fshared)
>  
>  #ifdef CONFIG_COMPAT
>  static void compat_exit_robust_list(struct task_struct *curr);
> -#else
> -static inline void compat_exit_robust_list(struct task_struct *curr) { }
>  #endif
>  
>  /*
> -- 
> 2.17.1
> 

Re: [PATCH] futex: remove unused empty compat_exit_robust_list()

[Thomas Gleixner]

Lukas,

On Fri, Nov 13 2020 at 18:20, Lukas Bulwahn wrote:
> Commit ba31c1a48538 ("futex: Move futex exit handling into futex code")
> introduced compat_exit_robust_list() with a full-fledged implementation for
> CONFIG_COMPAT, and an empty-body function for !CONFIG_COMPAT.
> However, compat_exit_robust_list() is only used in futex_mm_release() under
> ifdef CONFIG_COMPAT.
>
> Hence for !CONFIG_COMPAT, make CC=clang W=1 warns:
>
>   kernel/futex.c:314:20:
>     warning: unused function 'compat_exit_robust_list' [-Wunused-function]
>
> There is no need to declare the unused empty function for !CONFIG_COMPAT.
> Simply, remove it to address the -Wunused-function warning.

While I agree with the removal, I disagree with the reasoning.

The real argument is that the stub function is useless. Addressing the
warning is a side effect of the removal, nothing else.

Thanks,

        tglx

[tip: locking/core] futex: Remove unused empty compat_exit_robust_list()

[tip-bot2 for Lukas Bulwahn]

The following commit has been merged into the locking/core branch of tip:

Commit-ID:     932f8c64d38bb08f69c8c26a2216ba0c36c6daa8
Gitweb:        https://git.kernel.org/tip/932f8c64d38bb08f69c8c26a2216ba0c36c6daa8
Author:        Lukas Bulwahn <lukas.bulwahn@gmail.com>
AuthorDate:    Fri, 13 Nov 2020 18:20:12 +01:00
Committer:     Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Sat, 14 Nov 2020 01:15:35 +01:00

futex: Remove unused empty compat_exit_robust_list()

Commit ba31c1a48538 ("futex: Move futex exit handling into futex code")
introduced compat_exit_robust_list() with a full-fledged implementation for
CONFIG_COMPAT, and an empty-body function for !CONFIG_COMPAT.

However, compat_exit_robust_list() is only used in futex_mm_release() under
#ifdef CONFIG_COMPAT.

Hence for !CONFIG_COMPAT, make CC=clang W=1 warns:

  kernel/futex.c:314:20:
    warning: unused function 'compat_exit_robust_list' [-Wunused-function]

There is no need to declare the unused empty function for !CONFIG_COMPAT.

Simply remove it.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Link: https://lore.kernel.org/r/20201113172012.27221-1-lukas.bulwahn@gmail.com

---
 kernel/futex.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/kernel/futex.c b/kernel/futex.c
index ac32887..aee6ce2 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -310,8 +310,6 @@ static inline bool should_fail_futex(bool fshared)
 
 #ifdef CONFIG_COMPAT
 static void compat_exit_robust_list(struct task_struct *curr);
-#else
-static inline void compat_exit_robust_list(struct task_struct *curr) { }
 #endif
 
 /*