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Subjectlock_kernel() in kernel thread
Date
Hi,

I was wondering why it is necessary for the usb_hub_thread() in
drivers/usb/hub.c to have the big kernel lock with lock_kernel() ?

What is it with lock_kernel() anyway ?

extern __inline__ void lock_kernel(void)
{
#if 1
if (!++current->lock_depth)
spin_lock(&kernel_flag);
#else
__asm__ __volatile__(
"incl %1\n\t"
"jne 9f"
spin_lock_string
"\n9:"
:"=m" (__dummy_lock(&kernel_flag)),
"=m" (current->lock_depth));
#endif
}

Can someone explain what is behind lock_kernel() and
these changes (#if 1) in 2.4 ?

Is there any documentation for this out there ?

Thanks,

Armin
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