Messages in this thread | | | Date | Wed, 27 Jun 2001 11:41:55 +0200 | From | Andrea Arcangeli <> | Subject | Re: patch: highmem zero-bounce |
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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.
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).
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