From: John Ogness <john.ogness@linutronix.de>
Date: Sat, 16 Sep 2023 21:26:02 +0206
Subject: [PATCH 077/134] printk: Make static printk buffers available to nbcon
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz

The nbcon boot consoles also need printk buffers that are available
very early. Since the nbcon boot consoles will also be serialized
by the console_lock, they can use the same static printk buffers
that the legacy consoles are using.

Make the legacy static printk buffers available outside of printk.c
so they can be used by nbcon.c.

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/20230916192007.608398-4-john.ogness@linutronix.de
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 kernel/printk/internal.h |    2 ++
 kernel/printk/printk.c   |   13 +++++++++----
 2 files changed, 11 insertions(+), 4 deletions(-)

--- a/kernel/printk/internal.h
+++ b/kernel/printk/internal.h
@@ -86,6 +86,8 @@ static inline void nbcon_cleanup(struct
 
 #endif /* CONFIG_PRINTK */
 
+extern struct printk_buffers printk_shared_pbufs;
+
 /**
  * struct printk_buffers - Buffers to read/format/output printk messages.
  * @outbuf:	After formatting, contains text to output.
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -2847,6 +2847,13 @@ static bool printk_get_next_message(stru
 }
 
 /*
+ * Used as the printk buffers for non-panic, serialized console printing.
+ * This is for legacy (!CON_NBCON) as well as all boot (CON_BOOT) consoles.
+ * Its usage requires the console_lock held.
+ */
+struct printk_buffers printk_shared_pbufs;
+
+/*
  * Print one record for the given console. The record printed is whatever
  * record is the next available record for the given console.
  *
@@ -2863,12 +2870,10 @@ static bool printk_get_next_message(stru
  */
 static bool console_emit_next_record(struct console *con, bool *handover, int cookie)
 {
-	static struct printk_buffers pbufs;
-
 	bool is_extended = console_srcu_read_flags(con) & CON_EXTENDED;
-	char *outbuf = &pbufs.outbuf[0];
+	char *outbuf = &printk_shared_pbufs.outbuf[0];
 	struct printk_message pmsg = {
-		.pbufs = &pbufs,
+		.pbufs = &printk_shared_pbufs,
 	};
 	unsigned long flags;
 
