Messages in this thread | | | Date | Thu, 21 Dec 2006 17:35:33 +0000 | From | Russell King <> | Subject | Re: fuse, get_user_pages, flush_anon_page, aliasing caches and all that again |
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On Thu, Dec 21, 2006 at 05:29:42PM +0100, Arjan van de Ven wrote: > > > So, given all this additional complexity _and_ that it would only be > > safe on non-preempt UP, the question becomes: is using get_user_pages() > > to access the current processes memory space legal? Given the above, > > I would say not. > > I'd say that copy_from_user is the right api for this, not > get_user_pages + kmap hacks...
I would tend to agree.
So the question then comes down to: is there really an issue with using copy_*_user in fuse.
Bearing in mind that get_user_pages() simulates page faults in the memory it is trying to access, we're going to either take simulated page faults at that time, or real page faults in copy_*_user.
(I was just about to test a hacked up implementation of flush_anon_page() on my test system, but it seems its ethernet interface has warmed up too much and won't obtain a link with my switch... which makes download of kernels impossible. Hence it's going to have to wait a few hours for it to cool down.)
-- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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