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From:   John Ogness <john.ogness@linutronix.de>
To:     Petr Mladek <pmladek@suse.com>
Cc:     Sergey Senozhatsky <senozhatsky@chromium.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        linux-kernel@vger.kernel.org
Subject: [PATCH printk v2 02/11] printk: Let console_is_usable() handle nbcon
Date:   Wed, 20 Sep 2023 01:14:47 +0206
Message-Id: <20230919230856.661435-3-john.ogness@linutronix.de>
In-Reply-To: <20230919230856.661435-1-john.ogness@linutronix.de>
References: <20230919230856.661435-1-john.ogness@linutronix.de>
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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>
---
 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 6e8c1b02adae..69c8861be92c 100644
--- a/kernel/printk/internal.h
+++ b/kernel/printk/internal.h
@@ -80,6 +80,8 @@ 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.
@@ -94,8 +96,13 @@ 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