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authorFrederic Weisbecker <fweisbec@gmail.com>2013-02-22 00:05:07 +0100
committerFrederic Weisbecker <fweisbec@gmail.com>2013-02-22 00:05:07 +0100
commit4d4c4e24cf48400a24d33feffc7cca4f4e8cabe1 (patch)
treeb1d4862302c3cc56a10bed9605c9e9b0379a234b
parentaf7bdbafe3812af406ce07631effd2b96aae2dba (diff)
downloadlwn-4d4c4e24cf48400a24d33feffc7cca4f4e8cabe1.tar.gz
lwn-4d4c4e24cf48400a24d33feffc7cca4f4e8cabe1.zip
irq: Remove IRQ_EXIT_OFFSET workaround
The IRQ_EXIT_OFFSET trick was used to make sure the irq doesn't get preempted after we substract the HARDIRQ_OFFSET until we are entirely done with any code in irq_exit(). This workaround was necessary because some archs may call irq_exit() with irqs enabled and there is still some code in the end of this function that is not covered by the HARDIRQ_OFFSET but want to stay non-preemptible. Now that irq are always disabled in irq_exit(), the whole code is guaranteed not to be preempted. We can thus remove this hack. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
-rw-r--r--include/linux/hardirq.h2
-rw-r--r--kernel/softirq.c3
2 files changed, 1 insertions, 4 deletions
diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h
index 29eb805ea4a6..c1d6555d2567 100644
--- a/include/linux/hardirq.h
+++ b/include/linux/hardirq.h
@@ -118,10 +118,8 @@
#ifdef CONFIG_PREEMPT_COUNT
# define preemptible() (preempt_count() == 0 && !irqs_disabled())
-# define IRQ_EXIT_OFFSET (HARDIRQ_OFFSET-1)
#else
# define preemptible() 0
-# define IRQ_EXIT_OFFSET HARDIRQ_OFFSET
#endif
#if defined(CONFIG_SMP) || defined(CONFIG_GENERIC_HARDIRQS)
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 24a921bcf04f..f42ff97e1f8f 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -343,7 +343,7 @@ void irq_exit(void)
account_irq_exit_time(current);
trace_hardirq_exit();
- sub_preempt_count(IRQ_EXIT_OFFSET);
+ sub_preempt_count(HARDIRQ_OFFSET);
if (!in_interrupt() && local_softirq_pending())
invoke_softirq();
@@ -353,7 +353,6 @@ void irq_exit(void)
tick_nohz_irq_exit();
#endif
rcu_irq_exit();
- sched_preempt_enable_no_resched();
#ifndef __ARCH_IRQ_EXIT_IRQS_DISABLED
local_irq_restore(flags);
#endif