[PATCH printk v5 16/30] printk: Let console_is_usable() handle nbcon

John Ogness
2024-05-02T21:38:51Z

The nbcon consoles use a different printing callback. For nbcon
consoles, check for the write_atomic() callback instead of
write().

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
---
kernel/printk/internal.h | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/kernel/printk/internal.h b/kernel/printk/internal.h
index 339563dd60bb..943e8f083609 100644
--- a/kernel/printk/internal.h
+++ b/kernel/printk/internal.h
@@ -87,6 +87,8 @@ void nbcon_free(struct console *con);

/*
* Check if the given console is currently capable and allowed to print
+ * records. Note that this function does not consider the current context,
+ * which can also play a role in deciding if @con can be used to print
* records.
*
* Requires the console_srcu_read_lock.
@@ -101,8 +103,13 @@ static inline bool console_is_usable(struct console *con)
if ((flags & CON_SUSPENDED))
return false;

- if (!con->write)
- return false;
+ if (flags & CON_NBCON) {
+ if (!con->write_atomic)
+ return false;
+ } else {
+ if (!con->write)
+ return false;
+ }

/*
* Console drivers may assume that per-cpu resources have been
--
2.39.2