From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andi Kleen Subject: Re: Locking model for NAPI drivers Date: Wed, 01 Jun 2005 08:28:04 +0200 Message-ID: References: <20050531.154847.63995530.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: netdev@oss.sgi.com Return-path: To: "David S. Miller" In-Reply-To: <20050531.154847.63995530.davem@davemloft.net> (David S. Miller's message of "Tue, 31 May 2005 15:48:47 -0700 (PDT)") Sender: netdev-bounce@oss.sgi.com Errors-to: netdev-bounce@oss.sgi.com List-Id: netdev.vger.kernel.org "David S. Miller" writes: Stupid question, but... > I was doing some brainstorming to try and fix a nagging problem in > the tg3 driver which suggested that doing the SMP locking differently > might be the best and cleanest solution. > > The tg3 problem is that it can do an skb_copy() in HW IRQ disabled > context which is illegal. That is because of the kmap_atomic it does right? At least in the i386 highmem implementation I don't see any code that would be less safe in hard interrupt context compared to BHs. And FRV and mips look like they allow it too. > This fixes the skb_copy() we were doing with hw > IRQs disabled (which is illegal and triggers a > BUG() with HIGHMEM enabled). Which BUG did it trigger? -Andi