On Fri, Aug 18, 2017 at 03:54:15PM +0100, Punit Agrawal wrote: > When walking the page tables to resolve an address that points to > !p*d_present() entry, huge_pte_offset() returns inconsistent values > depending on the level of page table (PUD or PMD). > > It returns NULL in the case of a PUD entry while in the case of a PMD > entry, it returns a pointer to the page table entry. > > A similar inconsitency exists when handling swap entries - returns NULL > for a PUD entry while a pointer to the pte_t is retured for the PMD entry. > > Update huge_pte_offset() to make the behaviour consistent - return a > pointer to the pte_t for hugepage or swap entries. Only return NULL in > instances where we have a p*d_none() entry and the size parameter > doesn't match the hugepage size at this level of the page table. > > Document the behaviour to clarify the expected behaviour of this function. > This is to set clear semantics for architecture specific implementations > of huge_pte_offset(). > > Signed-off-by: Punit Agrawal <[email protected]> > Cc: Catalin Marinas <[email protected]> > Cc: Naoya Horiguchi <[email protected]> > Cc: Steve Capper <[email protected]> > Cc: Will Deacon <[email protected]> > Cc: Kirill A. Shutemov <[email protected]> > Cc: Michal Hocko <[email protected]> > Cc: Mike Kravetz <[email protected]>
FWIW: Reviewed-by: Catalin Marinas <[email protected]> Thanks.
