[PATCH printk v2 20/38] um: kmsg_dumper: use srcu console list iterator

John Ogness
2022-10-19T15:06:19Z

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>
---
arch/um/kernel/kmsg_dump.c | 11 ++++-------
1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/arch/um/kernel/kmsg_dump.c b/arch/um/kernel/kmsg_dump.c
index 3a3bbbb22090..44a418dec919 100644
--- a/arch/um/kernel/kmsg_dump.c
+++ b/arch/um/kernel/kmsg_dump.c
@@ -16,20 +16,17 @@ static void kmsg_dumper_stdout(struct kmsg_dumper *dumper,
struct console *con;
unsigned long flags;
size_t len = 0;
+ int cookie;

/* only dump kmsg when no console is available */
- if (!console_trylock())
- return;
-
- for_each_console(con) {
+ cookie = console_srcu_read_lock();
+ for_each_console_srcu(con) {
if (strcmp(con->name, "tty") == 0 &&
(console_is_enabled(con) || (con->flags & CON_CONSDEV))) {
break;
}
}
-
- console_unlock();
-
+ console_srcu_read_unlock(cookie);
if (con)
return;

--
2.30.2