mm: fix pfn_t to page conversion in vm_insert_mixed (03fc2da6) · Commits · 戴 / test

pfn_t_to_page() honors the flags in the pfn_t value to determine if a pfn is backed by a page. However, vm_insert_mixed() was originally written to use pfn_valid() to make this determination. To restore the old/correct behavior, ignore the pfn_t flags in the !pfn_t_devmap() case and fallback to trusting pfn_valid(). Fixes: ("mm, dax, gpu: convert vm_insert_mixed to pfn_t") Cc: Dave Hansen <dave@sr71.net> Cc: David Airlie <airlied@linux.ie> Reported-by:

Tomi Valkeinen <tomi.valkeinen@ti.com> Tested-by:

Tomi Valkeinen <tomi.valkeinen@ti.com> Signed-off-by:

Dan Williams <dan.j.williams@intel.com>

mm/memory.c

+7 −2

Original line number	Diff line number	Diff line
		@@ -1591,10 +1591,15 @@ int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
		* than insert_pfn). If a zero_pfn were inserted into a VM_MIXEDMAP
		* without pte special, it would there be refcounted as a normal page.
		*/
		if (!HAVE_PTE_SPECIAL && pfn_t_valid(pfn)) {
		if (!HAVE_PTE_SPECIAL && !pfn_t_devmap(pfn) && pfn_t_valid(pfn)) {
		struct page *page;

		page = pfn_t_to_page(pfn);
		/*
		* At this point we are committed to insert_page()
		* regardless of whether the caller specified flags that
		* result in pfn_t_has_page() == false.
		*/
		page = pfn_to_page(pfn_t_to_pfn(pfn));
		return insert_page(vma, addr, page, vma->vm_page_prot);
		}
		return insert_pfn(vma, addr, pfn, vma->vm_page_prot);

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