Re: [PATCH] read/write semaphore trylock routines - 2.4.6

[David Howells]

> A caveat for these trylock routines is that they use the cmpxchg
> instruction, which limits their usefulness on x86 to 486 and above.

Given that the implementation in that asm-i386/rwsem.h is based around usage
of the XADD instruction which exists everywhere the CMPXCHG instruction does
(I believe), you don't really need to put the #if clause around it.

You should also add spinlock versions too, which will cover most other archs.

David