Re: [PATCH] minimize lockdep_on/off side-effect

Mathieu Desnoyers
2007-01-24T17:56:01Z

Minimize lockdep_on/off side-effect on irq tracing in vprintk by using
raw_local_irq_save/restore _around_ lockdep_off/on().

It applies on the previous patch. It has the advantage of not losing the IRQ
events coming between the lockdep disabling and the irq disabling.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>

--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -530,8 +530,8 @@ asmlinkage int vprintk(const char *fmt, va_list args)
zap_locks();

/* This stops the holder of console_sem just where we want him */
+ raw_local_irq_save(flags);
lockdep_off();
- local_irq_save(flags);
spin_lock(&logbuf_lock);
printk_cpu = smp_processor_id();

@@ -640,8 +640,8 @@ asmlinkage int vprintk(const char *fmt, va_list args)
console_locked = 0;
up(&console_sem);
}
- local_irq_restore(flags);
lockdep_on();
+ raw_local_irq_restore(flags);
} else {
/*
* Someone else owns the drivers. We drop the spinlock, which
@@ -650,8 +650,8 @@ asmlinkage int vprintk(const char *fmt, va_list args)
*/
printk_cpu = UINT_MAX;
spin_unlock(&logbuf_lock);
- local_irq_restore(flags);
lockdep_on();
+ raw_local_irq_restore(flags);
}

preempt_enable();
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