[PATCH printk v5 31/40] netconsole: avoid CON_ENABLED misuse to track registration

John Ogness
2022-11-16T16:23:55Z

The CON_ENABLED flag is being misused to track whether or not the
extended console should be or has been registered. Instead use
a local variable to decide if the extended console should be
registered and console_is_registered() to determine if it has
been registered.

Also add a check in cleanup_netconsole() to only unregister the
extended console if it has been registered.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
---
drivers/net/netconsole.c | 21 +++++++++++----------
1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index bdff9ac5056d..4f4f79532c6c 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -332,10 +332,8 @@ static ssize_t enabled_store(struct config_item *item,
}

if (enabled) { /* true */
- if (nt->extended && !(netconsole_ext.flags & CON_ENABLED)) {
- netconsole_ext.flags |= CON_ENABLED;
+ if (nt->extended && !console_is_registered(&netconsole_ext))
register_console(&netconsole_ext);
- }

/*
* Skip netpoll_parse_options() -- all the attributes are
@@ -869,7 +867,7 @@ static void write_msg(struct console *con, const char *msg, unsigned int len)

static struct console netconsole_ext = {
.name = "netcon_ext",
- .flags = CON_EXTENDED, /* starts disabled, registered on first use */
+ .flags = CON_ENABLED | CON_EXTENDED,
.write = write_ext_msg,
};

@@ -883,6 +881,7 @@ static int __init init_netconsole(void)
{
int err;
struct netconsole_target *nt, *tmp;
+ bool extended = false;
unsigned long flags;
char *target_config;
char *input = config;
@@ -895,11 +894,12 @@ static int __init init_netconsole(void)
goto fail;
}
/* Dump existing printks when we register */
- if (nt->extended)
- netconsole_ext.flags |= CON_PRINTBUFFER |
- CON_ENABLED;
- else
+ if (nt->extended) {
+ extended = true;
+ netconsole_ext.flags |= CON_PRINTBUFFER;
+ } else {
netconsole.flags |= CON_PRINTBUFFER;
+ }

spin_lock_irqsave(&target_list_lock, flags);
list_add(&nt->list, &target_list);
@@ -915,7 +915,7 @@ static int __init init_netconsole(void)
if (err)
goto undonotifier;

- if (netconsole_ext.flags & CON_ENABLED)
+ if (extended)
register_console(&netconsole_ext);
register_console(&netconsole);
pr_info("network logging started\n");
@@ -945,7 +945,8 @@ static void __exit cleanup_netconsole(void)
{
struct netconsole_target *nt, *tmp;

- unregister_console(&netconsole_ext);
+ if (console_is_registered(&netconsole_ext))
+ unregister_console(&netconsole_ext);
unregister_console(&netconsole);
dynamic_netconsole_exit();
unregister_netdevice_notifier(&netconsole_netdev_notifier);
--
2.30.2