Merge tag 'printk-for-6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux

Pull printk updates from Petr Mladek:

 - Add NMI-safe SRCU reader API. It uses atomic_inc() instead of
   this_cpu_inc() on strong load-store architectures.

 - Introduce new console_list_lock to synchronize a manipulation of the
   list of registered consoles and their flags.

   This is a first step in removing the big-kernel-lock-like behavior of
   console_lock(). This semaphore still serializes console->write()
   calbacks against:

      - each other. It primary prevents potential races between early
        and proper console drivers using the same device.

      - suspend()/resume() callbacks and init() operations in some
        drivers.

      - various other operations in the tty/vt and framebufer
        susbsystems. It is likely that console_lock() serializes even
        operations that are not directly conflicting with the
        console->write() callbacks here. This is the most complicated
        big-kernel-lock aspect of the console_lock() that will be hard
        to untangle.

 - Introduce new console_srcu lock that is used to safely iterate and
   access the registered console drivers under SRCU read lock.

   This is a prerequisite for introducing atomic console drivers and
   console kthreads. It will reduce the complexity of serialization
   against normal consoles and console_lock(). Also it should remove the
   risk of deadlock during critical situations, like Oops or panic, when
   only atomic consoles are registered.

 - Check whether the console is registered instead of enabled on many
   locations. It was a historical leftover.

 - Cleanly force a preferred console in xenfb code instead of a dirty
   hack.

 - A lot of code and comment clean ups and improvements.

* tag 'printk-for-6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux: (47 commits)
  printk: htmldocs: add missing description
  tty: serial: sh-sci: use setup() callback for early console
  printk: relieve console_lock of list synchronization duties
  tty: serial: kgdboc: use console_list_lock to trap exit
  tty: serial: kgdboc: synchronize tty_find_polling_driver() and register_console()
  tty: serial: kgdboc: use console_list_lock for list traversal
  tty: serial: kgdboc: use srcu console list iterator
  proc: consoles: use console_list_lock for list iteration
  tty: tty_io: use console_list_lock for list synchronization
  printk, xen: fbfront: create/use safe function for forcing preferred
  netconsole: avoid CON_ENABLED misuse to track registration
  usb: early: xhci-dbc: use console_is_registered()
  tty: serial: xilinx_uartps: use console_is_registered()
  tty: serial: samsung_tty: use console_is_registered()
  tty: serial: pic32_uart: use console_is_registered()
  tty: serial: earlycon: use console_is_registered()
  tty: hvc: use console_is_registered()
  efi: earlycon: use console_is_registered()
  tty: nfcon: use console_is_registered()
  serial_core: replace uart_console_enabled() with uart_console_registered()
  ...

1 files changed, 12 insertions, 14 deletions

diff --git a/lib/test_printf.c b/lib/test_printf.c
index 5eb889679e4f..d6a5d4b5f884 100644
--- a/lib/test_printf.c
+++ b/lib/test_printf.c
@@ -692,31 +692,29 @@ flags(void)
 
 static void __init fwnode_pointer(void)
 {
-	const struct software_node softnodes[] = {
-		{ .name = "first", },
-		{ .name = "second", .parent = &softnodes[0], },
-		{ .name = "third", .parent = &softnodes[1], },
-		{ NULL /* Guardian */ }
-	};
-	const char * const full_name = "first/second/third";
+	const struct software_node first = { .name = "first" };
+	const struct software_node second = { .name = "second", .parent = &first };
+	const struct software_node third = { .name = "third", .parent = &second };
+	const struct software_node *group[] = { &first, &second, &third, NULL };
 	const char * const full_name_second = "first/second";
+	const char * const full_name_third = "first/second/third";
 	const char * const second_name = "second";
 	const char * const third_name = "third";
 	int rval;
 
-	rval = software_node_register_nodes(softnodes);
+	rval = software_node_register_node_group(group);
 	if (rval) {
 		pr_warn("cannot register softnodes; rval %d\n", rval);
 		return;
 	}
 
-	test(full_name_second, "%pfw", software_node_fwnode(&softnodes[1]));
-	test(full_name, "%pfw", software_node_fwnode(&softnodes[2]));
-	test(full_name, "%pfwf", software_node_fwnode(&softnodes[2]));
-	test(second_name, "%pfwP", software_node_fwnode(&softnodes[1]));
-	test(third_name, "%pfwP", software_node_fwnode(&softnodes[2]));
+	test(full_name_second, "%pfw", software_node_fwnode(&second));
+	test(full_name_third, "%pfw", software_node_fwnode(&third));
+	test(full_name_third, "%pfwf", software_node_fwnode(&third));
+	test(second_name, "%pfwP", software_node_fwnode(&second));
+	test(third_name, "%pfwP", software_node_fwnode(&third));
 
-	software_node_unregister_nodes(softnodes);
+	software_node_unregister_node_group(group);
 }
 
 static void __init fourcc_pointer(void)