On 9/22/20 11:27 AM, Christoph Hellwig wrote:

On Tue, Sep 22, 2020 at 11:24:20AM -0400, boris.ostrovsky@oracle.com wrote:

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On 9/22/20 10:58 AM, Christoph Hellwig wrote:

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On Mon, Sep 21, 2020 at 04:44:10PM -0400, boris.ostrovsky@oracle.com wrote:

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This will end up incrementing area->ptes pointer. So perhaps something like

pte_t **ptes = area->ptes;

if (apply_to_page_range(&init_mm, (unsigned long)area->area->addr,                         PAGE_SIZE * nr_frames, gnttab_apply, &ptes)) {

...

Yeah. What do you think of this version?

Oh yes, this is way better. This now can actually be read without trying to mentally unwind triple pointers. (You probably want to initialize idx to zero before calling apply_to_page_range(), I am not sure it's guaranteed to be zero).

Both instances are static variables, thus in .bss and initialized. So unless you insist I don't think we need a manual one.

Yes, you are right. (I thought perhaps this code could be called more than once but no, it can't).

-boris