diff mbox series

[v11,01/10] mm: Remove special swap entry functions

Message ID 20210616105937.23201-2-apopple@nvidia.com (mailing list archive)
State New, archived
Headers show
Series Add support for SVM atomics in Nouveau | expand

Commit Message

Alistair Popple June 16, 2021, 10:59 a.m. UTC 
Remove multiple similar inline functions for dealing with different
types of special swap entries.

Both migration and device private swap entries use the swap offset to
store a pfn. Instead of multiple inline functions to obtain a struct
page for each swap entry type use a common function
pfn_swap_entry_to_page(). Also open-code the various entry_to_pfn()
functions as this results is shorter code that is easier to understand.

Signed-off-by: Alistair Popple <apopple@nvidia.com>
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

---

v11:
* Rebased on mmotm

v9:
* Rebased on v5.13-rc2

v8:
* No changes

v7:
* Reworded commit message to include pfn_swap_entry_to_page()
* Added Christoph's Reviewed-by

v6:
* Removed redundant compound_page() call from inside PageLocked()
* Fixed a minor build issue for s390 reported by kernel test bot

v4:
* Added pfn_swap_entry_to_page()
* Reinstated check that migration entries point to locked pages
* Removed #define swapcache_prepare which isn't needed for CONFIG_SWAP=0
  builds
---
 arch/s390/mm/pgtable.c  |  2 +-
 fs/proc/task_mmu.c      | 23 +++++---------
 include/linux/swap.h    |  4 +--
 include/linux/swapops.h | 69 ++++++++++++++---------------------------
 mm/hmm.c                |  5 ++-
 mm/huge_memory.c        |  6 ++--
 mm/memcontrol.c         |  2 +-
 mm/memory.c             | 10 +++---
 mm/migrate.c            |  6 ++--
 mm/page_vma_mapped.c    |  6 ++--
 10 files changed, 51 insertions(+), 82 deletions(-)
diff mbox series

Patch

diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c
index 18205f851c24..eec3a9d7176e 100644
--- a/arch/s390/mm/pgtable.c
+++ b/arch/s390/mm/pgtable.c
@@ -691,7 +691,7 @@  static void ptep_zap_swap_entry(struct mm_struct *mm, swp_entry_t entry)
 	if (!non_swap_entry(entry))
 		dec_mm_counter(mm, MM_SWAPENTS);
 	else if (is_migration_entry(entry)) {
-		struct page *page = migration_entry_to_page(entry);
+		struct page *page = pfn_swap_entry_to_page(entry);
 
 		dec_mm_counter(mm, mm_counter(page));
 	}
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 95c8f1e8fea6..eb97468dfe4c 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -514,10 +514,8 @@  static void smaps_pte_entry(pte_t *pte, unsigned long addr,
 			} else {
 				mss->swap_pss += (u64)PAGE_SIZE << PSS_SHIFT;
 			}
-		} else if (is_migration_entry(swpent))
-			page = migration_entry_to_page(swpent);
-		else if (is_device_private_entry(swpent))
-			page = device_private_entry_to_page(swpent);
+		} else if (is_pfn_swap_entry(swpent))
+			page = pfn_swap_entry_to_page(swpent);
 	} else if (unlikely(IS_ENABLED(CONFIG_SHMEM) && mss->check_shmem_swap
 							&& pte_none(*pte))) {
 		page = xa_load(&vma->vm_file->f_mapping->i_pages,
@@ -549,7 +547,7 @@  static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr,
 		swp_entry_t entry = pmd_to_swp_entry(*pmd);
 
 		if (is_migration_entry(entry))
-			page = migration_entry_to_page(entry);
+			page = pfn_swap_entry_to_page(entry);
 	}
 	if (IS_ERR_OR_NULL(page))
 		return;
@@ -694,10 +692,8 @@  static int smaps_hugetlb_range(pte_t *pte, unsigned long hmask,
 	} else if (is_swap_pte(*pte)) {
 		swp_entry_t swpent = pte_to_swp_entry(*pte);
 
-		if (is_migration_entry(swpent))
-			page = migration_entry_to_page(swpent);
-		else if (is_device_private_entry(swpent))
-			page = device_private_entry_to_page(swpent);
+		if (is_pfn_swap_entry(swpent))
+			page = pfn_swap_entry_to_page(swpent);
 	}
 	if (page) {
 		int mapcount = page_mapcount(page);
@@ -1389,11 +1385,8 @@  static pagemap_entry_t pte_to_pagemap_entry(struct pagemapread *pm,
 			frame = swp_type(entry) |
 				(swp_offset(entry) << MAX_SWAPFILES_SHIFT);
 		flags |= PM_SWAP;
-		if (is_migration_entry(entry))
-			page = migration_entry_to_page(entry);
-
-		if (is_device_private_entry(entry))
-			page = device_private_entry_to_page(entry);
+		if (is_pfn_swap_entry(entry))
+			page = pfn_swap_entry_to_page(entry);
 	}
 
 	if (page && !PageAnon(page))
@@ -1454,7 +1447,7 @@  static int pagemap_pmd_range(pmd_t *pmdp, unsigned long addr, unsigned long end,
 			if (pmd_swp_uffd_wp(pmd))
 				flags |= PM_UFFD_WP;
 			VM_BUG_ON(!is_pmd_migration_entry(pmd));
-			page = migration_entry_to_page(entry);
+			page = pfn_swap_entry_to_page(entry);
 		}
 #endif
 
diff --git a/include/linux/swap.h b/include/linux/swap.h
index ac9bd84c905e..df7cbb6b3d3e 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -564,8 +564,8 @@  static inline void show_swap_cache_info(void)
 {
 }
 
-#define free_swap_and_cache(e) ({(is_migration_entry(e) || is_device_private_entry(e));})
-#define swapcache_prepare(e) ({(is_migration_entry(e) || is_device_private_entry(e));})
+/* used to sanity check ptes in zap_pte_range when CONFIG_SWAP=0 */
+#define free_swap_and_cache(e) is_pfn_swap_entry(e)
 
 static inline int add_swap_count_continuation(swp_entry_t swp, gfp_t gfp_mask)
 {
diff --git a/include/linux/swapops.h b/include/linux/swapops.h
index 708fbeb21dd3..c24c79812bc1 100644
--- a/include/linux/swapops.h
+++ b/include/linux/swapops.h
@@ -128,16 +128,6 @@  static inline bool is_write_device_private_entry(swp_entry_t entry)
 {
 	return unlikely(swp_type(entry) == SWP_DEVICE_WRITE);
 }
-
-static inline unsigned long device_private_entry_to_pfn(swp_entry_t entry)
-{
-	return swp_offset(entry);
-}
-
-static inline struct page *device_private_entry_to_page(swp_entry_t entry)
-{
-	return pfn_to_page(swp_offset(entry));
-}
 #else /* CONFIG_DEVICE_PRIVATE */
 static inline swp_entry_t make_device_private_entry(struct page *page, bool write)
 {
@@ -157,16 +147,6 @@  static inline bool is_write_device_private_entry(swp_entry_t entry)
 {
 	return false;
 }
-
-static inline unsigned long device_private_entry_to_pfn(swp_entry_t entry)
-{
-	return 0;
-}
-
-static inline struct page *device_private_entry_to_page(swp_entry_t entry)
-{
-	return NULL;
-}
 #endif /* CONFIG_DEVICE_PRIVATE */
 
 #ifdef CONFIG_MIGRATION
@@ -189,22 +169,6 @@  static inline int is_write_migration_entry(swp_entry_t entry)
 	return unlikely(swp_type(entry) == SWP_MIGRATION_WRITE);
 }
 
-static inline unsigned long migration_entry_to_pfn(swp_entry_t entry)
-{
-	return swp_offset(entry);
-}
-
-static inline struct page *migration_entry_to_page(swp_entry_t entry)
-{
-	struct page *p = pfn_to_page(swp_offset(entry));
-	/*
-	 * Any use of migration entries may only occur while the
-	 * corresponding page is locked
-	 */
-	BUG_ON(!PageLocked(compound_head(p)));
-	return p;
-}
-
 static inline void make_migration_entry_read(swp_entry_t *entry)
 {
 	*entry = swp_entry(SWP_MIGRATION_READ, swp_offset(*entry));
@@ -224,16 +188,6 @@  static inline int is_migration_entry(swp_entry_t swp)
 	return 0;
 }
 
-static inline unsigned long migration_entry_to_pfn(swp_entry_t entry)
-{
-	return 0;
-}
-
-static inline struct page *migration_entry_to_page(swp_entry_t entry)
-{
-	return NULL;
-}
-
 static inline void make_migration_entry_read(swp_entry_t *entryp) { }
 static inline void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep,
 					spinlock_t *ptl) { }
@@ -248,6 +202,29 @@  static inline int is_write_migration_entry(swp_entry_t entry)
 
 #endif
 
+static inline struct page *pfn_swap_entry_to_page(swp_entry_t entry)
+{
+	struct page *p = pfn_to_page(swp_offset(entry));
+
+	/*
+	 * Any use of migration entries may only occur while the
+	 * corresponding page is locked
+	 */
+	BUG_ON(is_migration_entry(entry) && !PageLocked(p));
+
+	return p;
+}
+
+/*
+ * A pfn swap entry is a special type of swap entry that always has a pfn stored
+ * in the swap offset. They are used to represent unaddressable device memory
+ * and to restrict access to a page undergoing migration.
+ */
+static inline bool is_pfn_swap_entry(swp_entry_t entry)
+{
+	return is_migration_entry(entry) || is_device_private_entry(entry);
+}
+
 struct page_vma_mapped_walk;
 
 #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
diff --git a/mm/hmm.c b/mm/hmm.c
index 943cb2ba4442..3b2dda71d0ed 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -214,7 +214,7 @@  static inline bool hmm_is_device_private_entry(struct hmm_range *range,
 		swp_entry_t entry)
 {
 	return is_device_private_entry(entry) &&
-		device_private_entry_to_page(entry)->pgmap->owner ==
+		pfn_swap_entry_to_page(entry)->pgmap->owner ==
 		range->dev_private_owner;
 }
 
@@ -257,8 +257,7 @@  static int hmm_vma_handle_pte(struct mm_walk *walk, unsigned long addr,
 			cpu_flags = HMM_PFN_VALID;
 			if (is_write_device_private_entry(entry))
 				cpu_flags |= HMM_PFN_WRITE;
-			*hmm_pfn = device_private_entry_to_pfn(entry) |
-					cpu_flags;
+			*hmm_pfn = swp_offset(entry) | cpu_flags;
 			return 0;
 		}
 
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index d513b0cd1161..327b8d9d8d2f 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1643,7 +1643,7 @@  int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
 
 			VM_BUG_ON(!is_pmd_migration_entry(orig_pmd));
 			entry = pmd_to_swp_entry(orig_pmd);
-			page = migration_entry_to_page(entry);
+			page = pfn_swap_entry_to_page(entry);
 			flush_needed = 0;
 		} else
 			WARN_ONCE(1, "Non present huge pmd without pmd migration enabled!");
@@ -2012,7 +2012,7 @@  static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
 			swp_entry_t entry;
 
 			entry = pmd_to_swp_entry(old_pmd);
-			page = migration_entry_to_page(entry);
+			page = pfn_swap_entry_to_page(entry);
 		} else {
 			page = pmd_page(old_pmd);
 			if (!PageDirty(page) && pmd_dirty(old_pmd))
@@ -2066,7 +2066,7 @@  static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
 		swp_entry_t entry;
 
 		entry = pmd_to_swp_entry(old_pmd);
-		page = migration_entry_to_page(entry);
+		page = pfn_swap_entry_to_page(entry);
 		write = is_write_migration_entry(entry);
 		young = false;
 		soft_dirty = pmd_swp_soft_dirty(old_pmd);
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index dce5154fbb8f..ae1f5d0cb581 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -5537,7 +5537,7 @@  static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
 	 * as special swap entry in the CPU page table.
 	 */
 	if (is_device_private_entry(ent)) {
-		page = device_private_entry_to_page(ent);
+		page = pfn_swap_entry_to_page(ent);
 		/*
 		 * MEMORY_DEVICE_PRIVATE means ZONE_DEVICE page and which have
 		 * a refcount of 1 when free (unlike normal page)
diff --git a/mm/memory.c b/mm/memory.c
index a5af7d854776..a6c5132354a2 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -729,7 +729,7 @@  copy_nonpresent_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
 		}
 		rss[MM_SWAPENTS]++;
 	} else if (is_migration_entry(entry)) {
-		page = migration_entry_to_page(entry);
+		page = pfn_swap_entry_to_page(entry);
 
 		rss[mm_counter(page)]++;
 
@@ -748,7 +748,7 @@  copy_nonpresent_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
 			set_pte_at(src_mm, addr, src_pte, pte);
 		}
 	} else if (is_device_private_entry(entry)) {
-		page = device_private_entry_to_page(entry);
+		page = pfn_swap_entry_to_page(entry);
 
 		/*
 		 * Update rss count even for unaddressable pages, as
@@ -1280,7 +1280,7 @@  static unsigned long zap_pte_range(struct mmu_gather *tlb,
 
 		entry = pte_to_swp_entry(ptent);
 		if (is_device_private_entry(entry)) {
-			struct page *page = device_private_entry_to_page(entry);
+			struct page *page = pfn_swap_entry_to_page(entry);
 
 			if (unlikely(details && details->check_mapping)) {
 				/*
@@ -1309,7 +1309,7 @@  static unsigned long zap_pte_range(struct mmu_gather *tlb,
 		else if (is_migration_entry(entry)) {
 			struct page *page;
 
-			page = migration_entry_to_page(entry);
+			page = pfn_swap_entry_to_page(entry);
 			rss[mm_counter(page)]--;
 		}
 		if (unlikely(!free_swap_and_cache(entry)))
@@ -3372,7 +3372,7 @@  vm_fault_t do_swap_page(struct vm_fault *vmf)
 			migration_entry_wait(vma->vm_mm, vmf->pmd,
 					     vmf->address);
 		} else if (is_device_private_entry(entry)) {
-			vmf->page = device_private_entry_to_page(entry);
+			vmf->page = pfn_swap_entry_to_page(entry);
 			ret = vmf->page->pgmap->ops->migrate_to_ram(vmf);
 		} else if (is_hwpoison_entry(entry)) {
 			ret = VM_FAULT_HWPOISON;
diff --git a/mm/migrate.c b/mm/migrate.c
index 8810c1421f5d..b4abb87249e1 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -296,7 +296,7 @@  void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep,
 	if (!is_migration_entry(entry))
 		goto out;
 
-	page = migration_entry_to_page(entry);
+	page = pfn_swap_entry_to_page(entry);
 	page = compound_head(page);
 
 	/*
@@ -337,7 +337,7 @@  void pmd_migration_entry_wait(struct mm_struct *mm, pmd_t *pmd)
 	ptl = pmd_lock(mm, pmd);
 	if (!is_pmd_migration_entry(*pmd))
 		goto unlock;
-	page = migration_entry_to_page(pmd_to_swp_entry(*pmd));
+	page = pfn_swap_entry_to_page(pmd_to_swp_entry(*pmd));
 	if (!get_page_unless_zero(page))
 		goto unlock;
 	spin_unlock(ptl);
@@ -2289,7 +2289,7 @@  static int migrate_vma_collect_pmd(pmd_t *pmdp,
 			if (!is_device_private_entry(entry))
 				goto next;
 
-			page = device_private_entry_to_page(entry);
+			page = pfn_swap_entry_to_page(entry);
 			if (!(migrate->flags &
 				MIGRATE_VMA_SELECT_DEVICE_PRIVATE) ||
 			    page->pgmap->owner != migrate->pgmap_owner)
diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c
index 3dd350a941aa..082e8073af56 100644
--- a/mm/page_vma_mapped.c
+++ b/mm/page_vma_mapped.c
@@ -96,7 +96,7 @@  static bool check_pte(struct page_vma_mapped_walk *pvmw)
 		if (!is_migration_entry(entry))
 			return false;
 
-		pfn = migration_entry_to_pfn(entry);
+		pfn = swp_offset(entry);
 	} else if (is_swap_pte(*pvmw->pte)) {
 		swp_entry_t entry;
 
@@ -105,7 +105,7 @@  static bool check_pte(struct page_vma_mapped_walk *pvmw)
 		if (!is_device_private_entry(entry))
 			return false;
 
-		pfn = device_private_entry_to_pfn(entry);
+		pfn = swp_offset(entry);
 	} else {
 		if (!pte_present(*pvmw->pte))
 			return false;
@@ -233,7 +233,7 @@  bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw)
 					return not_found(pvmw);
 				entry = pmd_to_swp_entry(pmde);
 				if (!is_migration_entry(entry) ||
-				    migration_entry_to_page(entry) != page)
+				    pfn_swap_entry_to_page(entry) != page)
 					return not_found(pvmw);
 				return true;
 			}