Messages in this thread | | | From | "H. Peter Anvin" <> | Subject | Re: How to transfer memory from PCI memory directly to user space safely and portable? | Date | 27 Nov 2000 10:36:34 -0800 |
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Followup to: <20001126151120.V2272@parcelfarce.linux.theplanet.co.uk> By author: Philipp Rumpf <prumpf@parcelfarce.linux.theplanet.co.uk> In newsgroup: linux.dev.kernel > > I hope count isn't provided by userspace here ? > > > 1. What happens if the user space memory is swapped to disk? Will > > verify_area() make sure that the memory is in physical RAM when it returns, > > or will it return -EFAULT, or will something even worse happen? > > On i386, you'll sleep implicitly waiting for the page fault to be handled; in > the generic case, anything could happen. >
That doesn't sound right. I would expect it to wait for the page to be brought in on any and all architectures, otherwise it seems rather impossible to write portable Linux kernel code.
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