linux-kernel - Re: [PATCH][next] binder: remove redundant variable page

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Date: Sat, 6 Jan 2024 16:29:45 +0000
From: Carlos Llamas <cmllamas@...gle.com>
To: Colin Ian King <colin.i.king@...il.com>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Arve Hjønnevåg <arve@...roid.com>,
	Todd Kjos <tkjos@...roid.com>, Martijn Coenen <maco@...roid.com>,
	Joel Fernandes <joel@...lfernandes.org>,
	Christian Brauner <brauner@...nel.org>,
	Suren Baghdasaryan <surenb@...gle.com>,
	kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH][next] binder: remove redundant variable page_addr

On Sat, Jan 06, 2024 at 03:04:57PM +0000, Colin Ian King wrote:
> From: Colin Ian King <colin.i.king@...el.com>
> 
> Variable page_addr is being assigned a value that is never read. The
> variable is redundant and can be removed.
> 
> Cleans up clang scan build warning:
> warning: Value stored to 'page_addr' is never read [deadcode.DeadStores]
> 
> Signed-off-by: Colin Ian King <colin.i.king@...el.com>
> ---
>  drivers/android/binder_alloc.c | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/drivers/android/binder_alloc.c b/drivers/android/binder_alloc.c
> index ea5e1ba2d0d7..ed4ca6689c75 100644
> --- a/drivers/android/binder_alloc.c
> +++ b/drivers/android/binder_alloc.c
> @@ -925,7 +925,6 @@ void binder_alloc_deferred_release(struct binder_alloc *alloc)
>  		int i;
>  
>  		for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
> -			unsigned long page_addr;
>  			bool on_lru;
>  
>  			if (!alloc->pages[i].page_ptr)
> @@ -933,7 +932,6 @@ void binder_alloc_deferred_release(struct binder_alloc *alloc)
>  
>  			on_lru = list_lru_del_obj(&binder_freelist,
>  					      &alloc->pages[i].lru);
> -			page_addr = alloc->buffer + i * PAGE_SIZE;
>  			binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
>  				     "%s: %d: page %d %s\n",
>  				     __func__, alloc->pid, i,
> -- 
> 2.43.0
> 

Thanks Colin. I was waiting for this warning to hit mainline so that I
could add the following tags to the fix:

  Fixes: 162c79731448 ("binder: avoid user addresses in debug logs")
  Reported-by: kernel test robot <lkp@...el.com>
  Closes: https://lore.kernel.org/oe-kbuild-all/202312060851.cudv98wG-lkp@intel.com/

Feel free to take them for a v2 if you'd like. Either way,
Acked-by: Carlos Llamas <cmllamas@...gle.com>

--
Carlos Llamas