Revert "printk: lock/unlock console only for new logbuf entries" (8749efc0) · Commits · 戴 / test

This reverts commit . This optimization will not apply once the transition to a lockless printk is complete. Rather than porting this optimization through the transition only to remove it anyway, just revert it now to simplify the transition. Signed-off-by:

John Ogness <john.ogness@linutronix.de> Reviewed-by:

Petr Mladek <pmladek@suse.com> Acked-by:

Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by:

Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20200709132344.760-4-john.ogness@linutronix.de

kernel/printk/printk.c

+3 −7

Original line number	Diff line number	Diff line
		@@ -1981,9 +1981,8 @@ asmlinkage int vprintk_emit(int facility, int level,
		const char *fmt, va_list args)
		{
		int printed_len;
		bool in_sched = false, pending_output;
		bool in_sched = false;
		unsigned long flags;
		u64 curr_log_seq;

		/* Suppress unimportant messages after panic happens */
		if (unlikely(suppress_printk))
		@@ -1999,13 +1998,11 @@ asmlinkage int vprintk_emit(int facility, int level,

		/* This stops the holder of console_sem just where we want him */
		logbuf_lock_irqsave(flags);
		curr_log_seq = log_next_seq;
		printed_len = vprintk_store(facility, level, dict, dictlen, fmt, args);
		pending_output = (curr_log_seq != log_next_seq);
		logbuf_unlock_irqrestore(flags);

		/* If called from the scheduler, we can not call up(). */
		if (!in_sched && pending_output) {
		if (!in_sched) {
		/*
		* Disable preemption to avoid being preempted while holding
		* console_sem which would prevent anyone from printing to
		@@ -2022,7 +2019,6 @@ asmlinkage int vprintk_emit(int facility, int level,
		preempt_enable();
		}

		if (pending_output)
		wake_up_klogd();
		return printed_len;
		}

Admin message