On Thu, May 25, 2023 at 08:31:14AM +0530, Anshuman Khandual wrote: > > +#ifndef set_ptes > > +#ifdef PFN_PTE_SHIFT > > +/** > > + * set_ptes - Map consecutive pages to a contiguous range of addresses. > > + * @mm: Address space to map the pages into. > > + * @addr: Address to map the first page at. > > + * @ptep: Page table pointer for the first entry. > > + * @pte: Page table entry for the first page. > > + * @nr: Number of pages to map. > > + * > > + * May be overridden by the architecture, or the architecture can define > > + * set_pte() and PFN_PTE_SHIFT. > > + * > > + * Context: The caller holds the page table lock. The pages all belong > > + * to the same folio. The PTEs are all in the same PMD. > > + */ > > +static inline void set_ptes(struct mm_struct *mm, unsigned long addr, > > + pte_t *ptep, pte_t pte, unsigned int nr) > > +{ > > + page_table_check_ptes_set(mm, addr, ptep, pte, nr); > > + > > + for (;;) { > > + set_pte(ptep, pte); > > + if (--nr == 0) > > + break; > > + ptep++; > > + pte = __pte(pte_val(pte) + (1UL << PFN_PTE_SHIFT)); > > + } > > +} > > +#ifndef set_pte_at > > +#define set_pte_at(mm, addr, ptep, pte) set_ptes(mm, addr, ptep, pte, 1) > > +#endif > > Should not there be a build phase call out when both set_ptes() and PFN_PTE_SHIFT > are not defined on a given platform ? How does that help? Either way you get a clear build error.