[PATCH] mm: extend prefault helpers to fault in more than PAGE_SIZE
Daniel Vetter
daniel at ffwll.ch
Thu Feb 16 07:14:25 PST 2012
On Thu, Feb 16, 2012 at 09:32:08PM +0800, Hillf Danton wrote:
> On Thu, Feb 16, 2012 at 8:01 PM, Daniel Vetter <daniel.vetter at ffwll.ch> wrote:
> > @@ -416,17 +417,20 @@ static inline int fault_in_pages_writeable(char __user *uaddr, int size)
> > * Writing zeroes into userspace here is OK, because we know that if
> > * the zero gets there, we'll be overwriting it.
> > */
> > - ret = __put_user(0, uaddr);
> > + while (uaddr <= end) {
> > + ret = __put_user(0, uaddr);
> > + if (ret != 0)
> > + return ret;
> > + uaddr += PAGE_SIZE;
> > + }
>
> What if
> uaddr & ~PAGE_MASK == PAGE_SIZE -3 &&
> end & ~PAGE_MASK == 2
I don't quite follow - can you elaborate upon which issue you're seeing?
-Daniel
--
Daniel Vetter
Mail: daniel at ffwll.ch
Mobile: +41 (0)79 365 57 48
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