From: Alejandro Colomar <alx.manpages@gmail.com>
Date: Sat, 14 May 2022 14:37:41 GMT
Subject: Re: [PATCH] getpriority: Only getpriority translation the priority values
Message-ID: <0fc70bd3-5883-47e4-1814-6ed6c756a400@gmail.com>
In-Reply-To: <20220510220821.1481801-1-tbodt@google.com>

Hi Theodore,

On 5/11/22 00:08, Theodore Dubois wrote:
> The translation is needed to avoid returning a negative number from a
> successful syscall, and this requirement doesn't apply to setpriority.
> See the implementation of getpriority in kernel/sys.c.
> 
> Signed-off-by: Theodore Dubois <tbodt@google.com>

Patch applied.

BTW, I had to manually edit the patch.
It's the second time I see this (I can't find the other one), your patch 
didn't apply for the following reason: the a/ and b/ prefixes in the 
file paths are missing.  Did you use git-format-patch(1) to produce the 
patch?  Can you reproduce this?

I CCd the git mailing list in case they know what's going on.

Thanks,

Alex

> ---
>   man2/getpriority.2 | 17 ++++-------------
>   1 file changed, 4 insertions(+), 13 deletions(-)
> 
> diff --git man2/getpriority.2 man2/getpriority.2

Should have been:
diff --git a/man2/getpriority.2 b/man2/getpriority.2

> index 3e1be3e6c..24c1b7f11 100644
> --- man2/getpriority.2
> +++ man2/getpriority.2

Should have been:

--- a/man2/getpriority.2
+++ b/man2/getpriority.2


> @@ -206,20 +206,11 @@ All BSD-like systems (SunOS 4.1.3, Ultrix 4.2,
>   manner as Linux 2.6.12 and later.
>   .\"
>   .SS C library/kernel differences
> -Within the kernel, nice values are actually represented
> -using the range 40..1
> -(since negative numbers are error codes) and these are the values
> -employed by the
> -.BR setpriority ()
> -and
> -.BR getpriority ()
> -system calls.
> -The glibc wrapper functions for these system calls handle the
> -translations between the user-land and kernel representations
> -of the nice value according to the formula
> +The getpriority system call returns nice values translated to the range 40..1,
> +since a negative return value would be interpreted as an error.
> +The glibc wrapper function for getpriority translates the value back according to the formula
>   .IR "unice\ =\ 20\ \-\ knice" .
> -(Thus, the kernel's 40..1 range corresponds to the
> -range \-20..19 as seen by user space.)
> +(Thus, the 40..1 range returned by the kernel corresponds to the range \-20..19 as seen by user space.)
>   .SH BUGS
>   According to POSIX, the nice value is a per-process setting.
>   However, under the current Linux/NPTL implementation of POSIX threads,

-- 
Alejandro Colomar
Linux man-pages comaintainer; https://www.kernel.org/doc/man-pages/
http://www.alejandro-colomar.es/