kernel-hacking-2024-linux-s.../arch/powerpc/include
Benjamin Herrenschmidt 529b7307d8 powerpc: Make rwsem use "long" type
This makes the 64-bit kernel use 64-bit signed integers for the counter
(effectively supporting 32-bit of active count in the semaphore), thus
avoiding things like overflow of the mmap_sem if you use a really crazy
number of threads

Note: Ideally the type in the structure should be atomic_long_t rather
than "long". However, there's some nasty issues with that. It needs to
be initialized statically -and- lib/rwsem.c does things like

        sem->count = RWSEM_UNLOCKED_VALUE;

Now, if you mix in the fact that atomic_* types are actually structures
with one member and note typedefs of a scalar, it makes its really nasty.

So I stuck to what we did before using a long and casts for now.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2010-08-24 14:41:48 +10:00
..
asm powerpc: Make rwsem use "long" type 2010-08-24 14:41:48 +10:00