From: Helge Deller <deller@gmx.de>
To: Petr Mladek <pmladek@suse.com>, John Ogness <john.ogness@linutronix.de>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>,
Steven Rostedt <rostedt@goodmis.org>,
Thomas Gleixner <tglx@linutronix.de>,
linux-kernel@vger.kernel.org,
"James E.J. Bottomley" <James.Bottomley@hansenpartnership.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-parisc@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH printk 11/18] printk: Convert console_drivers list to hlist
Date: Fri, 30 Sep 2022 18:53:54 +0200 [thread overview]
Message-ID: <db7bdf7a-597f-398e-9877-01e898733664@gmx.de> (raw)
In-Reply-To: <Yzb7Oh2Y8feej+Eh@alley>
On 9/30/22 16:20, Petr Mladek wrote:
> On Sat 2022-09-24 02:10:47, John Ogness wrote:
>> From: Thomas Gleixner <tglx@linutronix.de>
>>
>> Replace the open coded single linked list with a hlist so a conversion to
>> SRCU protected list walks can reuse the existing primitives.
>>
>> --- a/arch/parisc/kernel/pdc_cons.c
>> +++ b/arch/parisc/kernel/pdc_cons.c
>> @@ -272,15 +267,17 @@ void pdc_console_restart(bool hpmc)
>> if (pdc_console_initialized)
>> return;
>>
>> - if (!hpmc && console_drivers)
>> + if (!hpmc && !hlist_empty(&console_list))
>> return;
>>
>> /* If we've already seen the output, don't bother to print it again */
>> - if (console_drivers != NULL)
>> + if (!hlist_empty(&console_list))
>> pdc_cons.flags &= ~CON_PRINTBUFFER;
>>
>> - while ((console = console_drivers) != NULL)
>> - unregister_console(console_drivers);
>> + while (!hlist_empty(&console_list)) {
>> + unregister_console(READ_ONCE(hlist_entry(console_list.first,
>> + struct console, node)));
>
> The READ_ONCE() is in a wrong place. This is why it did not compile.
> It should be:
>
> unregister_console(hlist_entry(READ_ONCE(console_list.first),
> struct console,
> node));
>
> I know that it is all hope for good. But there is also a race between
> the hlist_empty() and hlist_entry().
I wonder if pdc_console() is still needed as it is today.
When this was written, early_console and such didn't worked for parisc
as it should. That's proably why we have this register/unregister in here.
Would it make sense, and would we gain something for this printk-series,
if I'd try to convert pdc_console to a standard earlycon or earlyprintk device?
Helge
next prev parent reply other threads:[~2022-09-30 16:54 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-24 0:04 [PATCH printk 00/18] preparation for threaded/atomic printing John Ogness
2022-09-24 0:04 ` [PATCH printk 08/18] parisc: Put console abuse into one place John Ogness
2022-09-24 0:20 ` Steven Rostedt
2022-09-30 7:54 ` Petr Mladek
2022-09-24 0:04 ` [PATCH printk 11/18] printk: Convert console_drivers list to hlist John Ogness
2022-09-24 10:53 ` Sergey Senozhatsky
2022-09-24 17:20 ` Helge Deller
2022-09-25 0:43 ` Sergey Senozhatsky
2022-09-24 17:27 ` Helge Deller
2022-09-30 14:20 ` Petr Mladek
2022-09-30 16:53 ` Helge Deller [this message]
2022-09-30 19:46 ` John Ogness
2022-09-30 22:41 ` Helge Deller
2022-09-24 6:44 ` [PATCH printk 00/18] preparation for threaded/atomic printing Greg Kroah-Hartman
2022-09-25 15:23 ` John Ogness
2022-09-24 9:47 ` Sergey Senozhatsky
2022-09-29 16:33 ` Petr Mladek
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=db7bdf7a-597f-398e-9877-01e898733664@gmx.de \
--to=deller@gmx.de \
--cc=James.Bottomley@hansenpartnership.com \
--cc=gregkh@linuxfoundation.org \
--cc=john.ogness@linutronix.de \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-parisc@vger.kernel.org \
--cc=pmladek@suse.com \
--cc=rostedt@goodmis.org \
--cc=senozhatsky@chromium.org \
--cc=tglx@linutronix.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).