On Thu, May 09, 2002, Pete Zaitcev <[EMAIL PROTECTED]> wrote: > > From: Johannes Erdfelt <[EMAIL PROTECTED]> > > Date: Thu, 9 May 2002 18:49:08 -0400 > > > We use clear_bit and set_bit because it's atomic and makes sure we don't > > race with the HC updating the same data. > > Check out the following e-mail, which I carefuly stowed away. > JE was included on the list of recipients.
Ahh yes, I remember that email now. I've been waiting on the new operation Linus mentioned since then. It looks like it's not 2.4 yet. I'll make a patch for x86 that includes such an operation and submit it to Marcelo. Thanks for being a pack rat and reminding us :) JE > ------------------------------------------------------ > From: Linus Torvalds <[EMAIL PROTECTED]> > To: Pete Zaitcev <[EMAIL PROTECTED]> > cc: Johannes Erdfelt <[EMAIL PROTECTED]> > Subject: Re: About atomicity of set_bit > In-Reply-To: <[EMAIL PROTECTED]> > Message-ID: <[EMAIL PROTECTED]> > > On Mon, 29 Oct 2001, Pete Zaitcev wrote: > > > > Do you really think that set_bit is atomic against DMA masters? > > JE said you did, see below. I do not think it is right. > > Heh. You're right. It _is_ atomic on my regular boxes, but not on UP. The > SMP-atomicity automatically gives DMA master atomicity on x86 too, but it > is certainly the case that that is not guaranteed on other architectures > anyway, even when they are SMP (although most sane architectures will work > in SMP). > > I guess the right thing to do is to make up a new operation that is > DMA-safe on UP too.. > > Linus > _______________________________________________________________ Have big pipes? SourceForge.net is looking for download mirrors. We supply the hardware. You get the recognition. Email Us: [EMAIL PROTECTED] _______________________________________________ [EMAIL PROTECTED] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
