Re: [PATCH 6/9] mm: convert PTE table entry to pte
Alexander Gordeev <[email protected]>
| Newsgroups | gmane.comp.freedesktop.xorg.drivers.intel,gmane.linux.kernel,gmane.comp.video.dri.devel,gmane.linux.ports.parisc,gmane.comp.emulators.xen.devel,gmane.linux.kernel.mm,gmane.linux.file-systems,gmane.linux.kernel.cross-arch,gmane.linux.kernel.bpf,gmane.linux.kernel.perf.user |
|---|---|
| Message-ID | <[email protected]> |
On Thu, Aug 06, 2026 at 09:38:44AM +0100, Muhammad Usama Anjum wrote: > The non-MMU stub receives hw_pte_t but returns a logical pte_t > value. Convert the stored entry through __pte_from_hw() before > returning. > > Signed-off-by: Muhammad Usama Anjum <[email protected]> > --- > include/linux/hugetlb.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h > index bc0b9c65aa1d0..9e8b391aa4bc9 100644 > --- a/include/linux/hugetlb.h > +++ b/include/linux/hugetlb.h > @@ -1283,7 +1283,7 @@ static inline pte_t huge_ptep_clear_flush(struct vm_area_struct *vma, > #ifdef CONFIG_MMU > return ptep_get(ptep); > #else > - return *ptep; > + return __pte_from_hw(*ptep); But this is a direct dereferencing, which breaks the whole point, isn't it? What about introducing something like pte_t ptep_get_sw(hw_pte_t *ptep) to be used in exactly situations like this? With that the semantics of hw_pte_t pointers becomes straightforward and closes the still ongoing "storage vs lifetime" discussion: hw_pte_t* points to HW-formatted page table entries ptep_get() is used to obtain HW-linked/attached entries, and may wire extra code like [1] or [2] ptep_get_sw() is used to obtain HW-unlinked/unattached entries and in most cases is just a direct dereference The caller should always know whether the entry is attached or not, so confusions like [3] are avoided. 1. https://lore.kernel.org/linux-mm/[email protected]/ 2. https://lore.kernel.org/linux-s390/[email protected]/ 3. https://lore.kernel.org/linux-s390/[email protected]/ > #endif > } > > -- > 2.47.3 >