Commit 8ac4bf01 authored by Petr Mladek's avatar Petr Mladek
Browse files

Merge branch 'rework/optimizations' into for-linus

parents 731ae3ad cf554387

kernel/printk/internal.h

+2 −0
Original line number Diff line number Diff line
@@ -64,6 +64,7 @@ struct dev_printk_info; 


extern struct printk_ringbuffer *prb;

extern bool printk_kthreads_running;

extern bool printk_kthreads_ready;

extern bool debug_non_panic_cpus;



__printf(4, 0)
@@ -180,6 +181,7 @@ static inline void nbcon_kthread_wake(struct console *con) 
#define PRINTKRB_RECORD_MAX	0



#define printk_kthreads_running (false)

#define printk_kthreads_ready (false)



/*

 * In !PRINTK builds we still export console_sem

kernel/printk/nbcon.c

+24 −2
Original line number Diff line number Diff line
@@ -1671,6 +1671,9 @@ bool nbcon_alloc(struct console *con) 
{

	struct nbcon_state state = { };



	/* Synchronize the kthread start. */

	lockdep_assert_console_list_lock_held();



	/* The write_thread() callback is mandatory. */

	if (WARN_ON(!con->write_thread))

		return false;
@@ -1701,12 +1704,15 @@ bool nbcon_alloc(struct console *con) 
			return false;

		}



		if (printk_kthreads_running) {

		if (printk_kthreads_ready && !have_boot_console) {

			if (!nbcon_kthread_create(con)) {

				kfree(con->pbufs);

				con->pbufs = NULL;

				return false;

			}



			/* Might be the first kthread. */

			printk_kthreads_running = true;

		}

	}
@@ -1716,14 +1722,30 @@ bool nbcon_alloc(struct console *con) 
/**

 * nbcon_free - Free and cleanup the nbcon console specific data

 * @con:	Console to free/cleanup nbcon data

 *

 * Important: @have_nbcon_console must be updated before calling

 *	this function. In particular, it can be set only when there

 *	is still another nbcon console registered.

 */

void nbcon_free(struct console *con)

{

	struct nbcon_state state = { };



	if (printk_kthreads_running)

	/* Synchronize the kthread stop. */

	lockdep_assert_console_list_lock_held();



	if (printk_kthreads_running) {

		nbcon_kthread_stop(con);



		/* Might be the last nbcon console.

		 *

		 * Do not rely on printk_kthreads_check_locked(). It is not

		 * called in some code paths, see nbcon_free() callers.

		 */

		if (!have_nbcon_console)

			printk_kthreads_running = false;

	}



	nbcon_state_set(con, &state);



	/* Boot consoles share global printk buffers. */

kernel/printk/printk.c

+11 −9
Original line number Diff line number Diff line
@@ -3574,7 +3574,7 @@ EXPORT_SYMBOL(console_resume); 
static int unregister_console_locked(struct console *console);



/* True when system boot is far enough to create printer threads. */

static bool printk_kthreads_ready __ro_after_init;

bool printk_kthreads_ready __ro_after_init;



static struct task_struct *printk_legacy_kthread;
@@ -3713,6 +3713,7 @@ static void printk_kthreads_check_locked(void) 
	if (!printk_kthreads_ready)

		return;



	/* Start or stop the legacy kthread when needed. */

	if (have_legacy_console || have_boot_console) {

		if (!printk_legacy_kthread &&

		    force_legacy_kthread() &&
@@ -4204,14 +4205,6 @@ static int unregister_console_locked(struct console *console) 
	 */

	synchronize_srcu(&console_srcu);



	if (console->flags & CON_NBCON)

		nbcon_free(console);



	console_sysfs_notify();



	if (console->exit)

		res = console->exit(console);



	/*

	 * With this console gone, the global flags tracking registered

	 * console types may have changed. Update them.
@@ -4232,6 +4225,15 @@ static int unregister_console_locked(struct console *console) 
	if (!found_nbcon_con)

		have_nbcon_console = found_nbcon_con;



	/* @have_nbcon_console must be updated before calling nbcon_free(). */

	if (console->flags & CON_NBCON)

		nbcon_free(console);



	console_sysfs_notify();



	if (console->exit)

		res = console->exit(console);



	/* Changed console list, may require printer threads to start/stop. */

	printk_kthreads_check_locked();