Am 2022-03-10 um 14:25 schrieb Matthew Wilcox:
On Thu, Mar 10, 2022 at 11:26:31AM -0600, Alex Sierra wrote:
@@ -606,7 +606,7 @@ static void print_bad_pte(struct vm_area_struct *vma, unsigned long addr,
- PFNMAP mappings in order to support COWable mappings.
*/ -struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr, +struct page *vm_normal_any_page(struct vm_area_struct *vma, unsigned long addr, pte_t pte) { unsigned long pfn = pte_pfn(pte); @@ -620,8 +620,6 @@ struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr, return NULL; if (is_zero_pfn(pfn)) return NULL;
if (pte_devmap(pte))return NULL;print_bad_pte(vma, addr, pte, NULL); return NULL;
... what?
Haven't you just made it so that a devmap page always prints a bad PTE message, and then returns NULL anyway?
Yeah, that was stupid. :/ I think the long-term goal was to get rid of pte_devmap. But for now, as long as we have pte_special with pte_devmap, we'll need a special case to handle that like a normal page.
I only see the PFN_DEV|PFN_MAP flags set in a few places: drivers/dax/device.c, drivers/nvdimm/pmem.c, fs/fuse/virtio_fs.c. I guess we need to test at least one of them for this patch series to make sure we're not breaking them.
Surely this should be:
if (pte_devmap(pte))
return NULL;
return pfn_to_page(pfn);or maybe
goto check_pfn;But I don't know about that highest_memmap_pfn check.
Looks to me like it should work. highest_memmap_pfn gets updated in memremap_pages -> pagemap_range -> move_pfn_range_to_zone -> memmap_init_range.
Regards, Felix
@@ -661,6 +659,22 @@ struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr, return pfn_to_page(pfn); }
+/*
- vm_normal_lru_page -- This function gets the "struct page" associated
- with a pte only for page cache and anon page. These pages are LRU handled.
- */
+struct page *vm_normal_lru_page(struct vm_area_struct *vma, unsigned long addr,
pte_t pte)It seems a shame to add a new function without proper kernel-doc.