linux-kernel - [PATCH v4 4/5] printk: nbcon: Export nbcon_write_context_set

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Message-Id: <20250915-nbcon-kgdboc-v4-4-e2b6753bb566@suse.com>
Date: Mon, 15 Sep 2025 08:20:33 -0300
From: Marcos Paulo de Souza <mpdesouza@...e.com>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>, 
 Petr Mladek <pmladek@...e.com>, Steven Rostedt <rostedt@...dmis.org>, 
 John Ogness <john.ogness@...utronix.de>, 
 Sergey Senozhatsky <senozhatsky@...omium.org>, 
 Jason Wessel <jason.wessel@...driver.com>, 
 Daniel Thompson <danielt@...nel.org>, 
 Douglas Anderson <dianders@...omium.org>
Cc: linux-kernel@...r.kernel.org, kgdb-bugreport@...ts.sourceforge.net, 
 Marcos Paulo de Souza <mpdesouza@...e.com>
Subject: [PATCH v4 4/5] printk: nbcon: Export nbcon_write_context_set_buf

This function will be used in the next patch to allow a driver to set
both the message and message length of a nbcon_write_context. This is
necessary because the function also initializes the ->unsafe_takeover
struct member. By using this helper we ensure that the struct is
initialized correctly.

Signed-off-by: Marcos Paulo de Souza <mpdesouza@...e.com>
---
 include/linux/console.h | 4 ++++
 kernel/printk/nbcon.c   | 2 +-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/include/linux/console.h b/include/linux/console.h
index b34c5a0b86303e2fb4583fa467d8be43761cf756..e0fc2608bd9d6a886f5ddc56d26f19b21ae8663d 100644
--- a/include/linux/console.h
+++ b/include/linux/console.h
@@ -602,6 +602,8 @@ static inline bool console_is_registered(const struct console *con)
 extern void nbcon_cpu_emergency_enter(void);
 extern void nbcon_cpu_emergency_exit(void);
 extern bool nbcon_can_proceed(struct nbcon_write_context *wctxt);
+extern void nbcon_write_context_set_buf(struct nbcon_write_context *wctxt,
+					char *buf, unsigned int len);
 extern bool nbcon_enter_unsafe(struct nbcon_write_context *wctxt);
 extern bool nbcon_exit_unsafe(struct nbcon_write_context *wctxt);
 extern void nbcon_reacquire_nobuf(struct nbcon_write_context *wctxt);
@@ -654,6 +656,8 @@ static inline bool console_is_usable(struct console *con, short flags, bool use_
 static inline void nbcon_cpu_emergency_enter(void) { }
 static inline void nbcon_cpu_emergency_exit(void) { }
 static inline bool nbcon_can_proceed(struct nbcon_write_context *wctxt) { return false; }
+static inline void nbcon_write_context_set_buf(struct nbcon_write_context *wctxt,
+					       char *buf, unsigned int len) { }
 static inline bool nbcon_enter_unsafe(struct nbcon_write_context *wctxt) { return false; }
 static inline bool nbcon_exit_unsafe(struct nbcon_write_context *wctxt) { return false; }
 static inline void nbcon_reacquire_nobuf(struct nbcon_write_context *wctxt) { }
diff --git a/kernel/printk/nbcon.c b/kernel/printk/nbcon.c
index 8644e019e2391797e623fcc124d37ed4d460ccd9..085930386d4c4accf69214d341c950aafb5d0b32 100644
--- a/kernel/printk/nbcon.c
+++ b/kernel/printk/nbcon.c
@@ -855,7 +855,7 @@ static bool __nbcon_context_update_unsafe(struct nbcon_context *ctxt, bool unsaf
 	return nbcon_context_can_proceed(ctxt, &cur);
 }
 
-static void nbcon_write_context_set_buf(struct nbcon_write_context *wctxt,
+void nbcon_write_context_set_buf(struct nbcon_write_context *wctxt,
 					char *buf, unsigned int len)
 {
 	struct nbcon_context *ctxt = &ACCESS_PRIVATE(wctxt, ctxt);

-- 
2.51.0