[PATCH] fs: Fix can_lseek_backward()

[Michael Grzeschik]

Hi Andrey,

On Wed, Nov 15, 2017 at 02:27:53PM -0800, Andrey Smirnov wrote:
> To quote corresponding man page:
> 
> "... Upon successful completion, lseek() returns the resulting offset
> location as measured in bytes from the beginning of the file."

Ack! I was reading that chapter beforehand but somehow did oversee it
and thought we receive the offset to the last position instead.

Thanks,
Michael

> Which for lseek(fd, 0, SEEK_SET) would be 0, so returning 'ret' as
> final step of the function would mean it'd never return anything but 0
> as well. Change the code to explicitly return '1' to fix the problem.
> 
> Fixes: 7c3f8d366 ("uimage: fix: add can_lseek_backward and use in uimage_open")
> Cc: Michael Grzeschik <m.grzeschik at pengutronix.de>
> Signed-off-by: Andrey Smirnov <andrew.smirnov at gmail.com>
> ---
> 
> Sascha:
> 
> This change should probably also go to master, since without enabling
> TFTP would break 'bootm' for uImages (at least it does on my setup)
> 
> Thanks,
> Andrey Smirnov
> 
>  include/fs.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/include/fs.h b/include/fs.h
> index f8a3b8bda..5c5fff870 100644
> --- a/include/fs.h
> +++ b/include/fs.h
> @@ -117,7 +117,7 @@ static inline int can_lseek_backward(int fd)
>  	if (ret < 0)
>  		return 0;
>  
> -	return ret;
> +	return 1;
>  }
>  
>  #define drv_to_fs_driver(d) container_of(d, struct fs_driver_d, drv)
> -- 
> 2.13.6
> 
> 

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