Commit 36652d0f authored by John Ogness's avatar John Ogness Committed by Petr Mladek
Browse files

printk: Add this_cpu_in_panic() 



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: default avatarJohn Ogness <john.ogness@linutronix.de>
Reviewed-by: default avatarPetr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20240207134103.1357162-8-john.ogness@linutronix.de


Signed-off-by: default avatarPetr Mladek <pmladek@suse.com>
parent 0ab7cdd0

kernel/printk/internal.h

+1 −0
Original line number Diff line number Diff line
@@ -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);

kernel/printk/printk.c

+23 −20
Original line number Diff line number Diff line
@@ -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

 *