um: kmsg_dumper: use srcu console list iterator

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>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20221116162152.193147-14-john.ogness@linutronix.de

diff --git a/arch/um/kernel/kmsg_dump.c b/arch/um/kernel/kmsg_dump.c
index 40abf1e9ccb16ab512121b672376459ea7a79d3b..427dd5a61a38a18595be9089ecbd53eed1e185b6 100644 (file)
--- 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;