From: Arnd Bergmann Date: Tue, 24 Aug 2010 12:06:38 +0000 Subject: Re: 64-bit ppc rwsem Message-Id: <201008241406.38539.arnd@arndb.de> List-Id: References: <20100818.222925.233689776.davem@davemloft.net> <20100823.151853.108794567.davem@davemloft.net> <1282613477.22370.485.camel@pasglop> In-Reply-To: <1282613477.22370.485.camel@pasglop> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Benjamin Herrenschmidt Cc: linuxppc-dev@lists.ozlabs.org, paulus@au.ibm.com, linux-kernel@vger.kernel.org, sparclinux@vger.kernel.org, akpm@linux-foundation.org, torvalds@linux-foundation.org, David Miller On Tuesday 24 August 2010, Benjamin Herrenschmidt wrote: > On Mon, 2010-08-23 at 15:18 -0700, David Miller wrote: > > > I've seen drivers in the past do trylocks at interrupt time ... tho > > I > > > 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