From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 27 Jun 2001 18:27:45 +0200 From: Jens Axboe Subject: Re: patch: highmem zero-bounce Message-ID: <20010627182745.D17905@suse.de> References: <20010626182215.C14460@suse.de> <20010627114155.A31910@athlon.random> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20010627114155.A31910@athlon.random> Sender: owner-linux-mm@kvack.org Return-Path: To: Andrea Arcangeli Cc: Linux Kernel , linux-mm@kvack.org, "ZINKEVICIUS,MATT (HP-Loveland,ex1)" List-ID: On Wed, Jun 27 2001, Andrea Arcangeli wrote: > On Tue, Jun 26, 2001 at 06:22:15PM +0200, Jens Axboe wrote: > > Hi, > > > > I updated the patches to 2.4.6-pre5, and removed the zone-dma32 > > addition. This means that machines with > 4GB of RAM will need to go all > > good, we can relax the ZONE_NORMAL later, that's a separate problem with > skipping the bounces. Exactly > I can see one mm corruption race condition in the patch, you missed > nested irq in the for kmap_irq_bh (PIO). You must _always_ > __cli/__save_flags before accessing the KMAP_IRQ_BH slot, in case the > remapping is required (so _only_ when the page is in the highmem zone). > Otherwise memory corruption will happen when the race triggers (for > example two ide disks in PIO mode doing I/O at the same time connected > to different irq sources). Ah yes, my bad. This requires some moving around, I'll post an updated patch later tonight. Thanks! -- Jens Axboe -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/