linux-kernel - Re: [PATCH 14/17] tty: srmcons: use 'count' directly in srmcons_do

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Date:   Wed, 22 Nov 2023 07:26:22 +0100
From:   Jiri Slaby <jirislaby@...nel.org>
To:     Richard Henderson <richard.henderson@...aro.org>,
        Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-serial <linux-serial@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Ivan Kokshaysky <ink@...assic.park.msu.ru>,
        Matt Turner <mattst88@...il.com>, linux-alpha@...r.kernel.org
Subject: Re: [PATCH 14/17] tty: srmcons: use 'count' directly in
 srmcons_do_write()

On 21. 11. 23, 18:48, Richard Henderson wrote:
> On 11/21/23 09:21, Ilpo Järvinen wrote:
>> On Tue, 21 Nov 2023, Jiri Slaby (SUSE) wrote:
>>
>>> Similarly to 'buf' in the previous patch, there is no need to have a
>>> separate counter ('remaining') in srmcons_do_write(). 'count' can be
>>> used directly which simplifies the code a bit.
>>>
>>> Note that the type of the current count ('c') is changed from 'long' to
>>> 'size_t' so that:
>>> 1) it is prepared for the upcoming change of 'count's type, and
>>> 2) is unsigned.
>>>
>>> Signed-off-by: Jiri Slaby (SUSE) <jirislaby@...nel.org>
>>> Cc: Richard Henderson <richard.henderson@...aro.org>
>>> Cc: Ivan Kokshaysky <ink@...assic.park.msu.ru>
>>> Cc: Matt Turner <mattst88@...il.com>
>>> Cc: linux-alpha@...r.kernel.org
>>> ---
>>>   arch/alpha/kernel/srmcons.c | 8 ++++----
>>>   1 file changed, 4 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/arch/alpha/kernel/srmcons.c b/arch/alpha/kernel/srmcons.c
>>> index b68c5af083cd..8025e2a882ed 100644
>>> --- a/arch/alpha/kernel/srmcons.c
>>> +++ b/arch/alpha/kernel/srmcons.c
>>> @@ -92,24 +92,24 @@ static int
>>>   srmcons_do_write(struct tty_port *port, const char *buf, int count)
>>>   {
>>>       static char str_cr[1] = "\r";
>>> -    long c, remaining = count;
>>> +    size_t c;
>>>       srmcons_result result;
>>>       int need_cr;
>>> -    while (remaining > 0) {
>>> +    while (count > 0) {
>>>           need_cr = 0;
>>>           /*
>>>            * Break it up into reasonable size chunks to allow a chance
>>>            * for input to get in
>>>            */
>>> -        for (c = 0; c < min_t(long, 128L, remaining) && !need_cr; c++)
>>> +        for (c = 0; c < min_t(size_t, 128U, count) && !need_cr; c++)
>>>               if (buf[c] == '\n')
>>>                   need_cr = 1;
>>>
>>>           while (c > 0) {
>>>               result.as_long = callback_puts(0, buf, c);
>>>               c -= result.bits.c;
>>> -            remaining -= result.bits.c;
>>> +            count -= result.bits.c;
>>>               buf += result.bits.c;
>>>               /*
>>>
>>
>> The patches in the series are in pretty odd order and it was not told
>> anywhere here that the return value is unused by the callers. I'd just
>> reorder the patches.
>>
> 
> Agreed, patch 15 needs to be before patch 14.  With that,

Ah, sure, I reordered the three to have buf and count changes close to 
each other, but didn't realize this.

thanks,
-- 
js
suse labs