Messages in this thread | | | Date | Fri, 30 Sep 2022 18:53:54 +0200 | Subject | Re: [PATCH printk 11/18] printk: Convert console_drivers list to hlist | From | Helge Deller <> |
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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
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