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printk: Add this_cpu_in_panic()

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There is already panic_in_progress() and other_cpu_in_panic(),
but checking if the current CPU is the panic CPU must still be
open coded.

Add this_cpu_in_panic() to complete the set.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20240207134103.1357162-8-john.ogness@linutronix.de
Signed-off-by: Petr Mladek <pmladek@suse.com>
This commit is contained in:
John Ogness 2024-02-07 14:46:56 +01:06 committed by Petr Mladek
parent 0ab7cdd004
commit 36652d0f3b
2 changed files with 24 additions and 20 deletions
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1
kernel/printk/internal.h
View file

@ -130,6 +130,7 @@ struct printk_message {
};
bool other_cpu_in_panic(void);
bool this_cpu_in_panic(void);
bool printk_get_next_message(struct printk_message *pmsg, u64 seq,
bool is_extended, bool may_supress);

43
kernel/printk/printk.c
View file

@ -347,6 +347,29 @@ static bool panic_in_progress(void)
return unlikely(atomic_read(&panic_cpu) != PANIC_CPU_INVALID);
}
/* Return true if a panic is in progress on the current CPU. */
bool this_cpu_in_panic(void)
{
/*
* We can use raw_smp_processor_id() here because it is impossible for
* the task to be migrated to the panic_cpu, or away from it. If
* panic_cpu has already been set, and we're not currently executing on
* that CPU, then we never will be.
*/
return unlikely(atomic_read(&panic_cpu) == raw_smp_processor_id());
}
/*
* Return true if a panic is in progress on a remote CPU.
*
* On true, the local CPU should immediately release any printing resources
* that may be needed by the panic CPU.
*/
bool other_cpu_in_panic(void)
{
return (panic_in_progress() && !this_cpu_in_panic());
}
/*
* This is used for debugging the mess that is the VT code by
* keeping track if we have the console semaphore held. It's
@ -2592,26 +2615,6 @@ static int console_cpu_notify(unsigned int cpu)
return 0;
}
/*
* Return true if a panic is in progress on a remote CPU.
*
* On true, the local CPU should immediately release any printing resources
* that may be needed by the panic CPU.
*/
bool other_cpu_in_panic(void)
{
if (!panic_in_progress())
return false;
/*
* We can use raw_smp_processor_id() here because it is impossible for
* the task to be migrated to the panic_cpu, or away from it. If
* panic_cpu has already been set, and we're not currently executing on
* that CPU, then we never will be.
*/
return atomic_read(&panic_cpu) != raw_smp_processor_id();
}
/**
* console_lock - block the console subsystem from printing
*