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SubjectRe: How to transfer memory from PCI memory directly to user space safely and portable?
Date
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.

-hpa
--
<hpa@transmeta.com> at work, <hpa@zytor.com> in private!
"Unix gives you enough rope to shoot yourself in the foot."
http://www.zytor.com/~hpa/puzzle.txt
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