Re: 64-bit ppc rwsem

On Tuesday 24 August 2010, Benjamin Herrenschmidt wrote:

On Mon, 2010-08-23 at 15:18 -0700, David Miller wrote:

quoted

quoted

I've seen drivers in the past do trylocks at interrupt time ... tho

I

quoted

agree it sucks.

Recently there was a thread where this was declared absolutely
illegal.

Maybe it was allowed, or sort-of worked before, and that's why it's
accounted for with IRQ disables in some implementations.  I don't
know. 

Ok, I'm happy to say it's a big no-no then.

Arnd, do you want to take over the moving to asm-generic and take care
of the spinlock case as well ? I can send Linus the first patch that
changes powerpc to use atomic_long now along with a few other things I
have pending, then you can pickup from there. Or do you want me to
continue pushing my patch as-is and we can look at cleaning up the
spinlock case separately ?

I'm currently doing too many things at once, please push in your existing
patch for now, we can continue from there.

For the asm-generic patch:
Acked-by: Arnd Bergmann <arnd@arndb.de>