[S390] prevent softirqs if delay is called disabled (bf6f6aa4) · Commits · 戴 / test

The new delay implementation uses the clock comparator and an external interrupt even if it is called disabled for interrupts. To do this all external interrupt source except clock comparator are switched of before enabling external interrupts. The external interrupt at the end of the delay period may not execute softirqs or we can end up in a dead-lock. Signed-off-by:

Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/lib/delay.c

+7 −0

Original line number	Diff line number	Diff line
		@@ -15,6 +15,7 @@
		#include <linux/delay.h>
		#include <linux/timex.h>
		#include <linux/irqflags.h>
		#include <linux/interrupt.h>

		void __delay(unsigned long loops)
		{
		@@ -35,7 +36,11 @@ void __udelay(unsigned long usecs)
		{
		u64 end, time, jiffy_timer = 0;
		unsigned long flags, cr0, mask, dummy;
		int irq_context;

		irq_context = in_interrupt();
		if (!irq_context)
		local_bh_disable();
		local_irq_save(flags);
		if (raw_irqs_disabled_flags(flags)) {
		jiffy_timer = S390_lowcore.jiffy_timer;
		@@ -62,6 +67,8 @@ void __udelay(unsigned long usecs)
		__ctl_load(cr0, 0, 0);
		S390_lowcore.jiffy_timer = jiffy_timer;
		}
		if (!irq_context)
		_local_bh_enable();
		set_clock_comparator(S390_lowcore.jiffy_timer);
		local_irq_restore(flags);
		}

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