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From: John Ogness <john.ogness@linutronix.de>
To: Petr Mladek <pmladek@suse.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	linux-kernel@vger.kernel.org, Richard Weinberger <richard@nod.at>,
	Anton Ivanov <anton.ivanov@cambridgegreys.com>,
	Johannes Berg <johannes@sipsolutions.net>,
	linux-um@lists.infradead.org
Subject: [PATCH printk v5 13/40] um: kmsg_dumper: use srcu console list iterator
Date: Wed, 16 Nov 2022 17:27:25 +0106	[thread overview]
Message-ID: <20221116162152.193147-14-john.ogness@linutronix.de> (raw)
In-Reply-To: <20221116162152.193147-1-john.ogness@linutronix.de>

Rather than using the console_lock to guarantee safe console list
traversal, use srcu console list iteration.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
---
 arch/um/kernel/kmsg_dump.c | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/arch/um/kernel/kmsg_dump.c b/arch/um/kernel/kmsg_dump.c
index 40abf1e9ccb1..427dd5a61a38 100644
--- a/arch/um/kernel/kmsg_dump.c
+++ b/arch/um/kernel/kmsg_dump.c
@@ -16,29 +16,26 @@ static void kmsg_dumper_stdout(struct kmsg_dumper *dumper,
 	struct console *con;
 	unsigned long flags;
 	size_t len = 0;
+	int cookie;
 
 	/*
 	 * If no consoles are available to output crash information, dump
 	 * the kmsg buffer to stdout.
 	 */
 
-	if (!console_trylock())
-		return;
-
-	for_each_console(con) {
+	cookie = console_srcu_read_lock();
+	for_each_console_srcu(con) {
 		/*
 		 * The ttynull console and disabled consoles are ignored
 		 * since they cannot output. All other consoles are
 		 * expected to output the crash information.
 		 */
 		if (strcmp(con->name, "ttynull") != 0 &&
-		    (con->flags & CON_ENABLED)) {
+		    (console_srcu_read_flags(con) & CON_ENABLED)) {
 			break;
 		}
 	}
-
-	console_unlock();
-
+	console_srcu_read_unlock(cookie);
 	if (con)
 		return;
 
-- 
2.30.2


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  parent reply	other threads:[~2022-11-16 16:22 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-16 16:21 [PATCH printk v5 00/40] reduce console_lock scope John Ogness
2022-11-16 16:21 ` [PATCH printk v5 07/40] um: kmsg_dump: only dump when no output console available John Ogness
2022-11-16 16:21 ` John Ogness [this message]
2022-11-18 11:22 ` [PATCH printk v5 00/40] reduce console_lock scope Petr Mladek
2022-11-18 14:55   ` Petr Mladek
2022-11-22 16:43 ` Greg Kroah-Hartman

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