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From:   "Guilherme G. Piccoli" <gpiccoli@igalia.com>
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Subject: [PATCH 14/30] panic: Properly identify the panic event to the notifiers' callbacks
Date:   Wed, 27 Apr 2022 19:49:08 -0300
Message-Id: <20220427224924.592546-15-gpiccoli@igalia.com>
In-Reply-To: <20220427224924.592546-1-gpiccoli@igalia.com>
References: <20220427224924.592546-1-gpiccoli@igalia.com>
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The notifiers infrastructure provides a way to pass an "id" to the
callbacks to determine what kind of event happened, i.e., what is
the reason behind they getting called.

The panic notifier currently pass 0, but this is soon to be
used in a multi-targeted notifier, so let's pass a meaningful
"id" over there.

Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
---
 include/linux/panic_notifier.h | 5 +++++
 kernel/panic.c                 | 2 +-
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/include/linux/panic_notifier.h b/include/linux/panic_notifier.h
index 41e32483d7a7..07dced83a783 100644
--- a/include/linux/panic_notifier.h
+++ b/include/linux/panic_notifier.h
@@ -9,4 +9,9 @@ extern struct atomic_notifier_head panic_notifier_list;
 
 extern bool crash_kexec_post_notifiers;
 
+enum panic_notifier_val {
+	PANIC_UNUSED,
+	PANIC_NOTIFIER = 0xDEAD,
+};
+
 #endif	/* _LINUX_PANIC_NOTIFIERS_H */
diff --git a/kernel/panic.c b/kernel/panic.c
index eb4dfb932c85..523bc9ccd0e9 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -287,7 +287,7 @@ void panic(const char *fmt, ...)
 	 * Run any panic handlers, including those that might need to
 	 * add information to the kmsg dump output.
 	 */
-	atomic_notifier_call_chain(&panic_notifier_list, 0, buf);
+	atomic_notifier_call_chain(&panic_notifier_list, PANIC_NOTIFIER, buf);
 
 	panic_print_sys_info(false);
 
-- 
2.36.0