Merging debian version 6.9.7-1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 0 insertions, 207 deletions

diff --git a/debian/patches-rt/0025-printk-Avoid-console_lock-dance-if-no-legacy-or-boot.patch b/debian/patches-rt/0025-printk-Avoid-console_lock-dance-if-no-legacy-or-boot.patch
deleted file mode 100644
index 8156ae1d14..0000000000
--- a/debian/patches-rt/0025-printk-Avoid-console_lock-dance-if-no-legacy-or-boot.patch
+++ /dev/null
@@ -1,207 +0,0 @@
-From: John Ogness <john.ogness@linutronix.de>
-Date: Tue, 26 Sep 2023 12:44:07 +0000
-Subject: [PATCH 25/48] printk: Avoid console_lock dance if no legacy or boot
- consoles
-Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.8/older/patches-6.8.2-rt11.tar.xz
-
-Currently the console lock is used to attempt legacy-type
-printing even if there are no legacy or boot consoles registered.
-If no such consoles are registered, the console lock does not
-need to be taken.
-
-Add tracking of legacy console registration and use it with
-boot console tracking to avoid unnecessary code paths, i.e.
-do not use the console lock if there are no boot consoles
-and no legacy consoles.
-
-Signed-off-by: John Ogness <john.ogness@linutronix.de>
-Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
----
- kernel/printk/printk.c |   79 +++++++++++++++++++++++++++++++++++++++----------
- 1 file changed, 64 insertions(+), 15 deletions(-)
-
---- a/kernel/printk/printk.c
-+++ b/kernel/printk/printk.c
-@@ -464,6 +464,13 @@ static int console_msg_format = MSG_FORM
- static DEFINE_MUTEX(syslog_lock);
- 
- /*
-+ * Specifies if a legacy console is registered. If legacy consoles are
-+ * present, it is necessary to perform the console lock/unlock dance
-+ * whenever console flushing should occur.
-+ */
-+static bool have_legacy_console;
-+
-+/*
-  * Specifies if a boot console is registered. If boot consoles are present,
-  * nbcon consoles cannot print simultaneously and must be synchronized by
-  * the console lock. This is because boot consoles and nbcon consoles may
-@@ -471,6 +478,14 @@ static DEFINE_MUTEX(syslog_lock);
-  */
- static bool have_boot_console;
- 
-+/*
-+ * Specifies if the console lock/unlock dance is needed for console
-+ * printing. If @have_boot_console is true, the nbcon consoles will
-+ * be printed serially along with the legacy consoles because nbcon
-+ * consoles cannot print simultaneously with boot consoles.
-+ */
-+#define printing_via_unlock (have_legacy_console || have_boot_console)
-+
- #ifdef CONFIG_PRINTK
- DECLARE_WAIT_QUEUE_HEAD(log_wait);
- /* All 3 protected by @syslog_lock. */
-@@ -2344,7 +2359,7 @@ asmlinkage int vprintk_emit(int facility
- 	printed_len = vprintk_store(facility, level, dev_info, fmt, args);
- 
- 	/* If called from the scheduler, we can not call up(). */
--	if (!in_sched) {
-+	if (!in_sched && printing_via_unlock) {
- 		/*
- 		 * The caller may be holding system-critical or
- 		 * timing-sensitive locks. Disable preemption during
-@@ -2653,7 +2668,7 @@ void resume_console(void)
-  */
- static int console_cpu_notify(unsigned int cpu)
- {
--	if (!cpuhp_tasks_frozen) {
-+	if (!cpuhp_tasks_frozen && printing_via_unlock) {
- 		/* If trylock fails, someone else is doing the printing */
- 		if (console_trylock())
- 			console_unlock();
-@@ -3194,7 +3209,8 @@ void console_flush_on_panic(enum con_flu
- 
- 	nbcon_atomic_flush_pending();
- 
--	console_flush_all(false, &next_seq, &handover);
-+	if (printing_via_unlock)
-+		console_flush_all(false, &next_seq, &handover);
- }
- 
- /*
-@@ -3531,6 +3547,8 @@ void register_console(struct console *ne
- 		 */
- 		nbcon_seq_force(newcon, newcon->seq);
- 		newcon->seq = 0;
-+	} else {
-+		have_legacy_console = true;
- 	}
- 
- 	if (newcon->flags & CON_BOOT)
-@@ -3605,6 +3623,7 @@ EXPORT_SYMBOL(register_console);
- /* Must be called under console_list_lock(). */
- static int unregister_console_locked(struct console *console)
- {
-+	bool found_legacy_con = false;
- 	bool found_boot_con = false;
- 	struct console *c;
- 	int res;
-@@ -3661,9 +3680,13 @@ static int unregister_console_locked(str
- 	for_each_console(c) {
- 		if (c->flags & CON_BOOT)
- 			found_boot_con = true;
-+		if (!(c->flags & CON_NBCON))
-+			found_legacy_con = true;
- 	}
- 	if (!found_boot_con)
- 		have_boot_console = found_boot_con;
-+	if (!found_legacy_con)
-+		have_legacy_console = found_legacy_con;
- 
- 	return res;
- }
-@@ -3824,22 +3847,34 @@ static bool __pr_flush(struct console *c
- 	seq = prb_next_reserve_seq(prb);
- 
- 	/* Flush the consoles so that records up to @seq are printed. */
--	console_lock();
--	console_unlock();
-+	if (printing_via_unlock) {
-+		console_lock();
-+		console_unlock();
-+	}
- 
- 	for (;;) {
- 		unsigned long begin_jiffies;
- 		unsigned long slept_jiffies;
--
--		diff = 0;
-+		bool use_console_lock = printing_via_unlock;
- 
- 		/*
--		 * Hold the console_lock to guarantee safe access to
--		 * console->seq. Releasing console_lock flushes more
--		 * records in case @seq is still not printed on all
--		 * usable consoles.
-+		 * Ensure the compiler does not optimize @use_console_lock to
-+		 * be @printing_via_unlock since the latter can change at any
-+		 * time.
- 		 */
--		console_lock();
-+		barrier();
-+
-+		diff = 0;
-+
-+		if (use_console_lock) {
-+			/*
-+			 * Hold the console_lock to guarantee safe access to
-+			 * console->seq. Releasing console_lock flushes more
-+			 * records in case @seq is still not printed on all
-+			 * usable consoles.
-+			 */
-+			console_lock();
-+		}
- 
- 		cookie = console_srcu_read_lock();
- 		for_each_console_srcu(c) {
-@@ -3859,6 +3894,7 @@ static bool __pr_flush(struct console *c
- 			if (flags & CON_NBCON) {
- 				printk_seq = nbcon_seq_read(c);
- 			} else {
-+				WARN_ON_ONCE(!use_console_lock);
- 				printk_seq = c->seq;
- 			}
- 
-@@ -3870,7 +3906,8 @@ static bool __pr_flush(struct console *c
- 		if (diff != last_diff && reset_on_progress)
- 			remaining_jiffies = timeout_jiffies;
- 
--		console_unlock();
-+		if (use_console_lock)
-+			console_unlock();
- 
- 		/* Note: @diff is 0 if there are no usable consoles. */
- 		if (diff == 0 || remaining_jiffies == 0)
-@@ -3940,6 +3977,7 @@ static void __wake_up_klogd(int val)
- 		return;
- 
- 	preempt_disable();
-+
- 	/*
- 	 * Guarantee any new records can be seen by tasks preparing to wait
- 	 * before this context checks if the wait queue is empty.
-@@ -3951,11 +3989,22 @@ static void __wake_up_klogd(int val)
- 	 *
- 	 * This pairs with devkmsg_read:A and syslog_print:A.
- 	 */
--	if (wq_has_sleeper(&log_wait) || /* LMM(__wake_up_klogd:A) */
--	    (val & PRINTK_PENDING_OUTPUT)) {
-+	if (!wq_has_sleeper(&log_wait)) /* LMM(__wake_up_klogd:A) */
-+		val &= ~PRINTK_PENDING_WAKEUP;
-+
-+	/*
-+	 * Simple read is safe. register_console() would flush a newly
-+	 * registered legacy console when writing the message about it
-+	 * being enabled.
-+	 */
-+	if (!printing_via_unlock)
-+		val &= ~PRINTK_PENDING_OUTPUT;
-+
-+	if (val) {
- 		this_cpu_or(printk_pending, val);
- 		irq_work_queue(this_cpu_ptr(&wake_up_klogd_work));
- 	}
-+
- 	preempt_enable();
- }
-