From: Marcos Paulo de Souza <mpdesouza@suse.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Petr Mladek <pmladek@suse.com>,
Steven Rostedt <rostedt@goodmis.org>,
John Ogness <john.ogness@linutronix.de>,
Sergey Senozhatsky <senozhatsky@chromium.org>,
Jason Wessel <jason.wessel@windriver.com>,
Daniel Thompson <danielt@kernel.org>,
Douglas Anderson <dianders@chromium.org>
Cc: linux-kernel@vger.kernel.org,
kgdb-bugreport@lists.sourceforge.net,
Marcos Paulo de Souza <mpdesouza@suse.com>
Subject: [PATCH v3 1/4] printk: nbcon: Export console_is_usable
Date: Tue, 02 Sep 2025 15:33:52 -0300 [thread overview]
Message-ID: <20250902-nbcon-kgdboc-v3-1-cd30a8106f1c@suse.com> (raw)
In-Reply-To: <20250902-nbcon-kgdboc-v3-0-cd30a8106f1c@suse.com>
The helper will be used on KDB code in the next commits.
Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>
---
include/linux/console.h | 44 ++++++++++++++++++++++++++++++++++++++++++++
kernel/printk/internal.h | 44 --------------------------------------------
2 files changed, 44 insertions(+), 44 deletions(-)
diff --git a/include/linux/console.h b/include/linux/console.h
index 8f10d0a85bb4536e4b0dda4e8ccbdf87978bbb4a..67af483574727c00eea1d5a1eacc994755c92607 100644
--- a/include/linux/console.h
+++ b/include/linux/console.h
@@ -605,6 +605,48 @@ extern bool nbcon_can_proceed(struct nbcon_write_context *wctxt);
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);
+
+/*
+ * 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.
+ */
+static inline bool console_is_usable(struct console *con, short flags, bool use_atomic)
+{
+ if (!(flags & CON_ENABLED))
+ return false;
+
+ if ((flags & CON_SUSPENDED))
+ return false;
+
+ if (flags & CON_NBCON) {
+ /* The write_atomic() callback is optional. */
+ if (use_atomic && !con->write_atomic)
+ return false;
+
+ /*
+ * For the !use_atomic case, @printk_kthreads_running is not
+ * checked because the write_thread() callback is also used
+ * via the legacy loop when the printer threads are not
+ * available.
+ */
+ } else {
+ if (!con->write)
+ return false;
+ }
+
+ /*
+ * Console drivers may assume that per-cpu resources have been
+ * allocated. So unless they're explicitly marked as being able to
+ * cope (CON_ANYTIME) don't call them until this CPU is officially up.
+ */
+ if (!cpu_online(raw_smp_processor_id()) && !(flags & CON_ANYTIME))
+ return false;
+
+ return true;
+}
+
#else
static inline void nbcon_cpu_emergency_enter(void) { }
static inline void nbcon_cpu_emergency_exit(void) { }
@@ -612,6 +654,8 @@ static inline bool nbcon_can_proceed(struct nbcon_write_context *wctxt) { return
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) { }
+static inline bool console_is_usable(struct console *con, short flags,
+ bool use_atomic) { return false; }
#endif
extern int console_set_on_cmdline;
diff --git a/kernel/printk/internal.h b/kernel/printk/internal.h
index ef282001f200fdbbacae3171932bf9f049037a85..bef97f2d11793191280bfb46f7f8b13bf2560351 100644
--- a/kernel/printk/internal.h
+++ b/kernel/printk/internal.h
@@ -112,47 +112,6 @@ bool nbcon_kthread_create(struct console *con);
void nbcon_kthread_stop(struct console *con);
void nbcon_kthreads_wake(void);
-/*
- * 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.
- */
-static inline bool console_is_usable(struct console *con, short flags, bool use_atomic)
-{
- if (!(flags & CON_ENABLED))
- return false;
-
- if ((flags & CON_SUSPENDED))
- return false;
-
- if (flags & CON_NBCON) {
- /* The write_atomic() callback is optional. */
- if (use_atomic && !con->write_atomic)
- return false;
-
- /*
- * For the !use_atomic case, @printk_kthreads_running is not
- * checked because the write_thread() callback is also used
- * via the legacy loop when the printer threads are not
- * available.
- */
- } else {
- if (!con->write)
- return false;
- }
-
- /*
- * Console drivers may assume that per-cpu resources have been
- * allocated. So unless they're explicitly marked as being able to
- * cope (CON_ANYTIME) don't call them until this CPU is officially up.
- */
- if (!cpu_online(raw_smp_processor_id()) && !(flags & CON_ANYTIME))
- return false;
-
- return true;
-}
-
/**
* nbcon_kthread_wake - Wake up a console printing thread
* @con: Console to operate on
@@ -204,9 +163,6 @@ static inline bool nbcon_legacy_emit_next_record(struct console *con, bool *hand
static inline void nbcon_kthread_wake(struct console *con) { }
static inline void nbcon_kthreads_wake(void) { }
-static inline bool console_is_usable(struct console *con, short flags,
- bool use_atomic) { return false; }
-
#endif /* CONFIG_PRINTK */
extern bool have_boot_console;
--
2.50.0
next prev parent reply other threads:[~2025-09-02 18:34 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-02 18:33 [PATCH v3 0/4] Handle NBCON consoles on KDB Marcos Paulo de Souza
2025-09-02 18:33 ` Marcos Paulo de Souza [this message]
2025-09-02 18:33 ` [PATCH v3 2/4] printk: nbcon: Introduce KDB helpers Marcos Paulo de Souza
2025-09-02 18:33 ` [PATCH v3 3/4] printk: nbcon: Allow KDB to acquire the NBCON context Marcos Paulo de Souza
2025-09-02 18:33 ` [PATCH v3 4/4] kdb: Adapt kdb_msg_write to work with NBCON consoles Marcos Paulo de Souza
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