Commit 248624f9 authored by David Hildenbrand's avatar David Hildenbrand Committed by Andrew Morton
Browse files

mm/memory: pass folio and pte to restore_exclusive_pte() 

Let's pass the folio and the pte to restore_exclusive_pte(), so we can
avoid repeated page_folio() and ptep_get().  To do that, pass the pte to
try_restore_exclusive_pte() and use a folio in there already.

While at it, just avoid the "swp_entry_t entry" variable in
try_restore_exclusive_pte() and add a folio-locked check to
restore_exclusive_pte().

Link: https://lkml.kernel.org/r/20250226132257.2826043-4-david@redhat.com


Signed-off-by: default avatarDavid Hildenbrand <david@redhat.com>
Reviewed-by: default avatarAlistair Popple <apopple@nvidia.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent db0f6e67

mm/memory.c

+14 −15
Original line number Diff line number Diff line
@@ -717,14 +717,13 @@ struct folio *vm_normal_folio_pmd(struct vm_area_struct *vma, 
#endif



static void restore_exclusive_pte(struct vm_area_struct *vma,

				  struct page *page, unsigned long address,

				  pte_t *ptep)

		struct folio *folio, struct page *page, unsigned long address,

		pte_t *ptep, pte_t orig_pte)

{

	struct folio *folio = page_folio(page);

	pte_t orig_pte;

	pte_t pte;



	orig_pte = ptep_get(ptep);

	VM_WARN_ON_FOLIO(!folio_test_locked(folio), folio);



	pte = pte_mkold(mk_pte(page, READ_ONCE(vma->vm_page_prot)));

	if (pte_swp_soft_dirty(orig_pte))

		pte = pte_mksoft_dirty(pte);
@@ -751,16 +750,15 @@ static void restore_exclusive_pte(struct vm_area_struct *vma, 
 * Tries to restore an exclusive pte if the page lock can be acquired without

 * sleeping.

 */

static int

try_restore_exclusive_pte(pte_t *src_pte, struct vm_area_struct *vma,

			unsigned long addr)

static int try_restore_exclusive_pte(struct vm_area_struct *vma,

		unsigned long addr, pte_t *ptep, pte_t orig_pte)

{

	swp_entry_t entry = pte_to_swp_entry(ptep_get(src_pte));

	struct page *page = pfn_swap_entry_to_page(entry);

	struct page *page = pfn_swap_entry_to_page(pte_to_swp_entry(orig_pte));

	struct folio *folio = page_folio(page);



	if (trylock_page(page)) {

		restore_exclusive_pte(vma, page, addr, src_pte);

		unlock_page(page);

	if (folio_trylock(folio)) {

		restore_exclusive_pte(vma, folio, page, addr, ptep, orig_pte);

		folio_unlock(folio);

		return 0;

	}
@@ -866,7 +864,7 @@ copy_nonpresent_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, 
		 * (ie. COW) mappings.

		 */

		VM_BUG_ON(!is_cow_mapping(src_vma->vm_flags));

		if (try_restore_exclusive_pte(src_pte, src_vma, addr))

		if (try_restore_exclusive_pte(src_vma, addr, src_pte, orig_pte))

			return -EBUSY;

		return -ENOENT;

	} else if (is_pte_marker_entry(entry)) {
@@ -3987,7 +3985,8 @@ static vm_fault_t remove_device_exclusive_entry(struct vm_fault *vmf) 
	vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address,

				&vmf->ptl);

	if (likely(vmf->pte && pte_same(ptep_get(vmf->pte), vmf->orig_pte)))

		restore_exclusive_pte(vma, vmf->page, vmf->address, vmf->pte);

		restore_exclusive_pte(vma, folio, vmf->page, vmf->address,

				      vmf->pte, vmf->orig_pte);



	if (vmf->pte)

		pte_unmap_unlock(vmf->pte, vmf->ptl);