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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: John Ogness <john.ogness@linutronix.de>,
	Sergey Senozhatsky <senozhatsky@chromium.org>,
	Petr Mladek <pmladek@suse.com>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH AUTOSEL 6.5 5/6] printk: Rename abandon_console_lock_in_panic() to other_cpu_in_panic()
Date: Fri,  8 Sep 2023 21:12:53 -0400	[thread overview]
Message-ID: <20230909011254.3581788-5-sashal@kernel.org> (raw)
In-Reply-To: <20230909011254.3581788-1-sashal@kernel.org>

From: John Ogness <john.ogness@linutronix.de>

[ Upstream commit 132a90d1527fedba2d95085c951ccf00dbbebe41 ]

Currently abandon_console_lock_in_panic() is only used to determine if
the current CPU should immediately release the console lock because
another CPU is in panic. However, later this function will be used by
the CPU to immediately release other resources in this situation.

Rename the function to other_cpu_in_panic(), which is a better
description and does not assume it is related to the console lock.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20230717194607.145135-8-john.ogness@linutronix.de
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 kernel/printk/internal.h |  2 ++
 kernel/printk/printk.c   | 15 ++++++++-------
 2 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/kernel/printk/internal.h b/kernel/printk/internal.h
index 2a17704136f1d..7d4979d5c3ce6 100644
--- a/kernel/printk/internal.h
+++ b/kernel/printk/internal.h
@@ -103,3 +103,5 @@ struct printk_message {
 	u64			seq;
 	unsigned long		dropped;
 };
+
+bool other_cpu_in_panic(void);
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index d5e29fad84234..08a9419046b65 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -2590,11 +2590,12 @@ static int console_cpu_notify(unsigned int cpu)
 }
 
 /*
- * Return true when this CPU should unlock console_sem without pushing all
- * messages to the console. This reduces the chance that the console is
- * locked when the panic CPU tries to use it.
+ * 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.
  */
-static bool abandon_console_lock_in_panic(void)
+bool other_cpu_in_panic(void)
 {
 	if (!panic_in_progress())
 		return false;
@@ -2621,7 +2622,7 @@ void console_lock(void)
 	might_sleep();
 
 	/* On panic, the console_lock must be left to the panic cpu. */
-	while (abandon_console_lock_in_panic())
+	while (other_cpu_in_panic())
 		msleep(1000);
 
 	down_console_sem();
@@ -2643,7 +2644,7 @@ EXPORT_SYMBOL(console_lock);
 int console_trylock(void)
 {
 	/* On panic, the console_lock must be left to the panic cpu. */
-	if (abandon_console_lock_in_panic())
+	if (other_cpu_in_panic())
 		return 0;
 	if (down_trylock_console_sem())
 		return 0;
@@ -2959,7 +2960,7 @@ static bool console_flush_all(bool do_cond_resched, u64 *next_seq, bool *handove
 			any_progress = true;
 
 			/* Allow panic_cpu to take over the consoles safely. */
-			if (abandon_console_lock_in_panic())
+			if (other_cpu_in_panic())
 				goto abandon;
 
 			if (do_cond_resched)
-- 
2.40.1


  parent reply	other threads:[~2023-09-09  1:14 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-09  1:12 [PATCH AUTOSEL 6.5 1/6] printk: Reduce console_unblank() usage in unsafe scenarios Sasha Levin
2023-09-09  1:12 ` [PATCH AUTOSEL 6.5 2/6] printk: Keep non-panic-CPUs out of console lock Sasha Levin
2023-09-09  1:12 ` [PATCH AUTOSEL 6.5 3/6] printk: Do not take console lock for console_flush_on_panic() Sasha Levin
2023-09-09  1:12 ` [PATCH AUTOSEL 6.5 4/6] printk: Consolidate console deferred printing Sasha Levin
2023-09-09  1:12 ` Sasha Levin [this message]
2023-09-09  1:12 ` [PATCH AUTOSEL 6.5 6/6] thermal/drivers/sun8i: Free calibration nvmem after reading it Sasha Levin
2023-09-09 12:37   ` Mark Brown
2023-09-18 17:28     ` Sasha Levin

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