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: 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>

diff --git a/kernel/printk/internal.h b/kernel/printk/internal.h
index 6c2afee5ef6204b5ce4483505e5e8c2034874bc7..ac2d9750e5f81719fac01e093a92bbcc4cef1571 100644 (file)
--- a/kernel/printk/internal.h
+++ b/kernel/printk/internal.h
@@ -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);
 

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 22bb45d8f2f210357c26824812a81b6c576508bb..82dc2c7949b73b5c601b89da89e6886c98dafe3c 100644 (file)
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -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
  *