From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
Petr Mladek <pmladek@suse.com>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Steven Rostedt <rostedt@goodmis.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 4/5] console: Avoid positive return code from unregister_console()
Date: Tue, 28 Jan 2020 18:37:26 +0900 [thread overview]
Message-ID: <20200128093726.GE115889@google.com> (raw)
In-Reply-To: <20200128092235.GX32742@smile.fi.intel.com>
On (20/01/28 11:22), Andy Shevchenko wrote:
> On Tue, Jan 28, 2020 at 01:43:32PM +0900, Sergey Senozhatsky wrote:
> > On (20/01/27 13:47), Andy Shevchenko wrote:
> > [..]
> > > res = _braille_unregister_console(console);
> > > - if (res)
> > > + if (res < 0)
> > > return res;
> > > + if (res > 0)
> > > + return 0;
> > >
> > > - res = 1;
> > > + res = -ENODEV;
> > > console_lock();
> > > if (console_drivers == console) {
> > > console_drivers=console->next;
> > > @@ -2838,6 +2840,9 @@ int unregister_console(struct console *console)
> > > if (!res && (console->flags & CON_EXTENDED))
> > > nr_ext_console_drivers--;
> > >
> > > + if (res && !(console->flags & CON_ENABLED))
> > > + res = 0;
> >
> > Console is not on the console_drivers list. Why does !ENABLED case
> > require extra handling?
>
> It's mirroring (to some extend) the register_console() abort conditions.
Could you please explain?
I see the "newcon->flags & CON_ENABLED" error out path. I'm guessing,
that the expectation is that this is how we filter out consoles which
were not matched (there is that "newcon->flags |= CON_ENABLED" several
lines earlier.) So this looks like the assumption is that consoles don't
have CON_ENABLED bit set prior to register_console(), as far as I understand.
Well, look at these
...
drivers/net/netconsole.c: .flags = CON_ENABLED,
drivers/tty/ehv_bytechan.c: .flags = CON_PRINTBUFFER | CON_ENABLED,
drivers/tty/serial/mux.c: .flags = CON_ENABLED | CON_PRINTBUFFER,
...
-ss
next prev parent reply other threads:[~2020-01-28 9:37 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-27 11:47 [PATCH v3 1/5] console: Don't perform test for CON_BRL flag Andy Shevchenko
2020-01-27 11:47 ` [PATCH v3 2/5] console: Drop double check for console_drivers being non-NULL Andy Shevchenko
2020-01-29 13:24 ` Petr Mladek
2020-01-27 11:47 ` [PATCH v3 3/5] console: Use for_each_console() helper in unregister_console() Andy Shevchenko
2020-01-29 14:11 ` Petr Mladek
2020-01-27 11:47 ` [PATCH v3 4/5] console: Avoid positive return code from unregister_console() Andy Shevchenko
2020-01-28 4:43 ` Sergey Senozhatsky
2020-01-28 9:22 ` Andy Shevchenko
2020-01-28 9:25 ` Sergey Senozhatsky
2020-01-28 9:37 ` Sergey Senozhatsky [this message]
2020-01-28 9:52 ` Andy Shevchenko
2020-01-30 9:04 ` Petr Mladek
2020-01-30 9:58 ` Andy Shevchenko
2020-01-30 12:22 ` Petr Mladek
2020-01-30 13:13 ` Andy Shevchenko
2020-01-27 11:47 ` [PATCH v3 5/5] console: Introduce ->exit() callback Andy Shevchenko
2020-01-28 5:17 ` Sergey Senozhatsky
2020-01-28 9:44 ` Andy Shevchenko
2020-01-29 13:41 ` Sergey Senozhatsky
2020-01-29 14:25 ` Andy Shevchenko
2020-01-29 15:12 ` Sergey Senozhatsky
2020-01-29 16:50 ` Sergey Senozhatsky
2020-01-30 13:14 ` Andy Shevchenko
2020-01-30 13:22 ` Petr Mladek
2020-01-30 13:39 ` Andy Shevchenko
2020-01-30 9:09 ` Petr Mladek
2020-01-30 10:01 ` Andy Shevchenko
2020-01-29 12:29 ` [PATCH v3 1/5] console: Don't perform test for CON_BRL flag Petr Mladek
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