From: John Ogness Date: Tue, 20 Aug 2024 08:35:43 +0206 Subject: [PATCH 17/54] printk: Let console_is_usable() handle nbcon Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.11/older/patches-6.11-rt7.tar.xz 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 Reviewed-by: Petr Mladek Link: https://lore.kernel.org/r/20240820063001.36405-18-john.ogness@linutronix.de Signed-off-by: Petr Mladek Signed-off-by: Sebastian Andrzej Siewior --- kernel/printk/internal.h | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) --- a/kernel/printk/internal.h +++ b/kernel/printk/internal.h @@ -86,6 +86,8 @@ 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. @@ -100,8 +102,13 @@ static inline bool console_is_usable(str 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