From: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jirislaby@kernel.org>, Petr Mladek <pmladek@suse.com>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Steven Rostedt <rostedt@goodmis.org>,
John Ogness <john.ogness@linutronix.de>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] tty: use printk_safe context at tty_msg()
Date: Tue, 6 Apr 2021 20:16:43 +0900 [thread overview]
Message-ID: <4898f140-d7ed-14d3-e24f-8f51fc6bc003@i-love.sakura.ne.jp> (raw)
In-Reply-To: <YGwJZWwQCNQwlVLK@kroah.com>
On 2021/04/06 16:10, Greg Kroah-Hartman wrote:
> On Tue, Apr 06, 2021 at 02:31:43PM +0900, Tetsuo Handa wrote:
>> On 2021/04/06 13:51, Jiri Slaby wrote:
>>> On 03. 04. 21, 6:14, Tetsuo Handa wrote:
>>>> --- a/include/linux/tty.h
>>>> +++ b/include/linux/tty.h
>>>> @@ -14,6 +14,7 @@
>>>> #include <uapi/linux/tty.h>
>>>> #include <linux/rwsem.h>
>>>> #include <linux/llist.h>
>>>> +#include <../../kernel/printk/internal.h>
>>>
>>> Including printk's internal header in linux/tty.h doesn't look correct to me.
>>>
>>
>> This is because this patch wants __printk_safe_enter()/__printk_safe_exit()
>> without #ifdef'ing CONFIG_PRINTK.
>
> Then those functions need to be "properly" exported, not placed only in
> an "internal.h" file that obviously should not be included from anywhere
> like this.
>
>> Peter and Sergey, what should we do?
>> Can we move printk_safe_enter_irqsave()/printk_safe_exit_irqrestore() to include/linux/printk.h ?
>
> Are you sure that is the only way to resolve this?
Publishing printk_safe_enter_irqsave() etc. was once proposed at
https://lkml.kernel.org/r/20181016050428.17966-3-sergey.senozhatsky@gmail.com and
Peter Zijlstra did not like such change. But we reconfirmed that "tty_port lock must
switch to printk_safe" at https://lkml.kernel.org/r/20190219013254.GA20023@jagdpanzerIV .
Two years has elapsed since a completely new printk implementation which would not
use printk_safe context was proposed, but printk_safe context is still remaining.
Therefore, we might need to tolerate, with a warning that printk_safe_enter_irqsave()
etc. are not intended for general use, use of printk_safe context for tty_msg() and
tty_buffer_alloc().
next prev parent reply other threads:[~2021-04-06 11:17 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-03 4:14 [PATCH] tty: use printk_safe context at tty_msg() Tetsuo Handa
2021-04-03 6:52 ` kernel test robot
2021-04-03 10:11 ` [PATCH] printk: Make multiple inclusion of kernel/printk/internal.h safe Tetsuo Handa
2021-04-06 4:51 ` [PATCH] tty: use printk_safe context at tty_msg() Jiri Slaby
2021-04-06 5:31 ` Tetsuo Handa
2021-04-06 7:10 ` Greg Kroah-Hartman
2021-04-06 11:16 ` Tetsuo Handa [this message]
2021-04-06 13:42 ` Greg Kroah-Hartman
2021-04-06 15:10 ` Petr Mladek
2021-04-06 16:22 ` Tetsuo Handa
2021-04-06 19:10 ` Greg Kroah-Hartman
2021-04-07 9:20 ` Petr Mladek
2021-04-07 13:26 ` [PATCH v2] tty: use printk_deferred() " Tetsuo Handa
2021-04-07 13:48 ` Greg Kroah-Hartman
2021-04-07 14:24 ` Tetsuo Handa
2021-04-12 10:39 ` How to handle concurrent access to /dev/ttyprintk ? Tetsuo Handa
2021-04-12 10:44 ` Greg Kroah-Hartman
2021-04-12 11:25 ` Tetsuo Handa
2021-04-12 12:04 ` Greg Kroah-Hartman
2021-04-14 0:45 ` Tetsuo Handa
2021-04-14 11:11 ` Tetsuo Handa
2021-04-14 16:15 ` Samo Pogačnik
2021-04-15 0:22 ` [PATCH] ttyprintk: Add TTY hangup callback Tetsuo Handa
2021-04-18 11:16 ` Samo Pogačnik
2021-04-22 10:02 ` Greg Kroah-Hartman
2021-04-23 4:22 ` Jiri Slaby
2021-04-23 9:55 ` Samo Pogačnik
2021-04-23 10:12 ` Tetsuo Handa
2021-04-23 19:47 ` Samo Pogačnik
2021-04-24 1:16 ` Tetsuo Handa
2021-04-24 9:57 ` Samo Pogačnik
2021-04-26 10:00 ` Petr Mladek
2021-04-26 16:42 ` Samo Pogačnik
2021-04-27 10:08 ` Petr Mladek
2021-04-27 11:31 ` Samo Pogačnik
2021-04-23 10:28 ` Jiri Slaby
2021-04-23 12:23 ` [PATCH] ttyprintk: Add TTY port shutdown callback Samo Pogačnik
2021-04-12 12:41 ` How to handle concurrent access to /dev/ttyprintk ? Samo Pogačnik
2021-04-13 9:41 ` Petr Mladek
2021-04-13 11:10 ` Samo Pogačnik
2021-04-13 14:32 ` Petr Mladek
2021-04-13 15:22 ` Samo Pogačnik
2021-04-14 17:36 ` Petr Mladek
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