[PATCH V2 0/2] enable irqs when waiting for rwlocks

[Petr Tesarik <ptesarik@suse.cz>]

New in V2:
 * get rid of ugly #ifdef's in kernel/spinlock.h
 * convert __raw_{read|write}_lock_flags to an inline func

SGI has observed that on large systems, interrupts are not serviced for
a long period of time when waiting for a rwlock. The following patch
series re-enables irqs while waiting for the lock, resembling the code
which is already there for spinlocks.

I only made the ia64 version, because the patch adds some overhead to
the fast path. I assume there is currently no demand to have this for
other architectures, because the systems are not so large. Of course,
the possibility to implement raw_{read|write}_lock_flags for any
architecture is still there.

Petr Tesarik