pagewalk: separate function pointers from iterator data

The mm_walk structure currently mixed data and code. Split out the operations vectors into a new mm_walk_ops structure, and while we are changing the API also declare the mm_walk structure inside the walk_page_range and walk_page_vma functions. Based on patch from Linus Torvalds. Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Christoph Hellwig <[email protected]> Reviewed-by: Thomas Hellstrom <[email protected]> Reviewed-by: Steven Price <[email protected]> Reviewed-by: Jason Gunthorpe <[email protected]> Signed-off-by: Jason Gunthorpe <[email protected]>
kmaincent · Sep 7, 2019 · 7b86ac3 · 7b86ac3
1 parent a520110
commit 7b86ac3
Show file tree

Hide file tree

Showing 13 changed files with 251 additions and 244 deletions.
diff --git a/arch/openrisc/kernel/dma.c b/arch/openrisc/kernel/dma.c
@@ -44,6 +44,10 @@ page_set_nocache(pte_t *pte, unsigned long addr,
 	return 0;
 }
 
+static const struct mm_walk_ops set_nocache_walk_ops = {
+	.pte_entry		= page_set_nocache,
+};
+
 static int
 page_clear_nocache(pte_t *pte, unsigned long addr,
 		   unsigned long next, struct mm_walk *walk)
@@ -59,6 +63,10 @@ page_clear_nocache(pte_t *pte, unsigned long addr,
 	return 0;
 }
 
+static const struct mm_walk_ops clear_nocache_walk_ops = {
+	.pte_entry		= page_clear_nocache,
+};
+
 /*
  * Alloc "coherent" memory, which for OpenRISC means simply uncached.
  *
@@ -81,10 +89,6 @@ arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
 {
 	unsigned long va;
 	void *page;
-	struct mm_walk walk = {
-		.pte_entry = page_set_nocache,
-		.mm = &init_mm
-	};
 
 	page = alloc_pages_exact(size, gfp | __GFP_ZERO);
 	if (!page)
@@ -99,7 +103,8 @@ arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
 	 * We need to iterate through the pages, clearing the dcache for
 	 * them and setting the cache-inhibit bit.
 	 */
-	if (walk_page_range(va, va + size, &walk)) {
+	if (walk_page_range(&init_mm, va, va + size, &set_nocache_walk_ops,
+			NULL)) {
 		free_pages_exact(page, size);
 		return NULL;
 	}
@@ -112,13 +117,10 @@ arch_dma_free(struct device *dev, size_t size, void *vaddr,
 		dma_addr_t dma_handle, unsigned long attrs)
 {
 	unsigned long va = (unsigned long)vaddr;
-	struct mm_walk walk = {
-		.pte_entry = page_clear_nocache,
-		.mm = &init_mm
-	};
 
 	/* walk_page_range shouldn't be able to fail here */
-	WARN_ON(walk_page_range(va, va + size, &walk));
+	WARN_ON(walk_page_range(&init_mm, va, va + size,
+			&clear_nocache_walk_ops, NULL));
 
 	free_pages_exact(vaddr, size);
 }

diff --git a/arch/powerpc/mm/book3s64/subpage_prot.c b/arch/powerpc/mm/book3s64/subpage_prot.c
@@ -139,14 +139,14 @@ static int subpage_walk_pmd_entry(pmd_t *pmd, unsigned long addr,
 	return 0;
 }
 
+static const struct mm_walk_ops subpage_walk_ops = {
+	.pmd_entry	= subpage_walk_pmd_entry,
+};
+
 static void subpage_mark_vma_nohuge(struct mm_struct *mm, unsigned long addr,
 				    unsigned long len)
 {
 	struct vm_area_struct *vma;
-	struct mm_walk subpage_proto_walk = {
-		.mm = mm,
-		.pmd_entry = subpage_walk_pmd_entry,
-	};
 
 	/*
 	 * We don't try too hard, we just mark all the vma in that range
@@ -163,7 +163,7 @@ static void subpage_mark_vma_nohuge(struct mm_struct *mm, unsigned long addr,
 		if (vma->vm_start >= (addr + len))
 			break;
 		vma->vm_flags |= VM_NOHUGEPAGE;
-		walk_page_vma(vma, &subpage_proto_walk);
+		walk_page_vma(vma, &subpage_walk_ops, NULL);
 		vma = vma->vm_next;
 	}
 }

diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c
@@ -2521,13 +2521,9 @@ static int __zap_zero_pages(pmd_t *pmd, unsigned long start,
 	return 0;
 }
 
-static inline void zap_zero_pages(struct mm_struct *mm)
-{
-	struct mm_walk walk = { .pmd_entry = __zap_zero_pages };
-
-	walk.mm = mm;
-	walk_page_range(0, TASK_SIZE, &walk);
-}
+static const struct mm_walk_ops zap_zero_walk_ops = {
+	.pmd_entry	= __zap_zero_pages,
+};
 
 /*
  * switch on pgstes for its userspace process (for kvm)
@@ -2546,7 +2542,7 @@ int s390_enable_sie(void)
 	mm->context.has_pgste = 1;
 	/* split thp mappings and disable thp for future mappings */
 	thp_split_mm(mm);
-	zap_zero_pages(mm);
+	walk_page_range(mm, 0, TASK_SIZE, &zap_zero_walk_ops, NULL);
 	up_write(&mm->mmap_sem);
 	return 0;
 }
@@ -2589,12 +2585,13 @@ static int __s390_enable_skey_hugetlb(pte_t *pte, unsigned long addr,
 	return 0;
 }
 
+static const struct mm_walk_ops enable_skey_walk_ops = {
+	.hugetlb_entry		= __s390_enable_skey_hugetlb,
+	.pte_entry		= __s390_enable_skey_pte,
+};
+
 int s390_enable_skey(void)
 {
-	struct mm_walk walk = {
-		.hugetlb_entry = __s390_enable_skey_hugetlb,
-		.pte_entry = __s390_enable_skey_pte,
-	};
 	struct mm_struct *mm = current->mm;
 	struct vm_area_struct *vma;
 	int rc = 0;
@@ -2614,8 +2611,7 @@ int s390_enable_skey(void)
 	}
 	mm->def_flags &= ~VM_MERGEABLE;
 
-	walk.mm = mm;
-	walk_page_range(0, TASK_SIZE, &walk);
+	walk_page_range(mm, 0, TASK_SIZE, &enable_skey_walk_ops, NULL);
 
 out_up:
 	up_write(&mm->mmap_sem);
@@ -2633,13 +2629,14 @@ static int __s390_reset_cmma(pte_t *pte, unsigned long addr,
 	return 0;
 }
 
+static const struct mm_walk_ops reset_cmma_walk_ops = {
+	.pte_entry		= __s390_reset_cmma,
+};
+
 void s390_reset_cmma(struct mm_struct *mm)
 {
-	struct mm_walk walk = { .pte_entry = __s390_reset_cmma };
-
 	down_write(&mm->mmap_sem);
-	walk.mm = mm;
-	walk_page_range(0, TASK_SIZE, &walk);
+	walk_page_range(mm, 0, TASK_SIZE, &reset_cmma_walk_ops, NULL);
 	up_write(&mm->mmap_sem);
 }
 EXPORT_SYMBOL_GPL(s390_reset_cmma);
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
@@ -513,7 +513,9 @@ static int smaps_pte_hole(unsigned long addr, unsigned long end,
 
 	return 0;
 }
-#endif
+#else
+#define smaps_pte_hole		NULL
+#endif /* CONFIG_SHMEM */
 
 static void smaps_pte_entry(pte_t *pte, unsigned long addr,
 		struct mm_walk *walk)
@@ -729,21 +731,24 @@ static int smaps_hugetlb_range(pte_t *pte, unsigned long hmask,
 	}
 	return 0;
 }
+#else
+#define smaps_hugetlb_range	NULL
 #endif /* HUGETLB_PAGE */
 
+static const struct mm_walk_ops smaps_walk_ops = {
+	.pmd_entry		= smaps_pte_range,
+	.hugetlb_entry		= smaps_hugetlb_range,
+};
+
+static const struct mm_walk_ops smaps_shmem_walk_ops = {
+	.pmd_entry		= smaps_pte_range,
+	.hugetlb_entry		= smaps_hugetlb_range,
+	.pte_hole		= smaps_pte_hole,
+};
+
 static void smap_gather_stats(struct vm_area_struct *vma,
 			     struct mem_size_stats *mss)
 {
-	struct mm_walk smaps_walk = {
-		.pmd_entry = smaps_pte_range,
-#ifdef CONFIG_HUGETLB_PAGE
-		.hugetlb_entry = smaps_hugetlb_range,
-#endif
-		.mm = vma->vm_mm,
-	};
-
-	smaps_walk.private = mss;
-
 #ifdef CONFIG_SHMEM
 	/* In case of smaps_rollup, reset the value from previous vma */
 	mss->check_shmem_swap = false;
@@ -765,12 +770,13 @@ static void smap_gather_stats(struct vm_area_struct *vma,
 			mss->swap += shmem_swapped;
 		} else {
 			mss->check_shmem_swap = true;
-			smaps_walk.pte_hole = smaps_pte_hole;
+			walk_page_vma(vma, &smaps_shmem_walk_ops, mss);
+			return;
 		}
 	}
 #endif
 	/* mmap_sem is held in m_start */
-	walk_page_vma(vma, &smaps_walk);
+	walk_page_vma(vma, &smaps_walk_ops, mss);
 }
 
 #define SEQ_PUT_DEC(str, val) \
@@ -1118,6 +1124,11 @@ static int clear_refs_test_walk(unsigned long start, unsigned long end,
 	return 0;
 }
 
+static const struct mm_walk_ops clear_refs_walk_ops = {
+	.pmd_entry		= clear_refs_pte_range,
+	.test_walk		= clear_refs_test_walk,
+};
+
 static ssize_t clear_refs_write(struct file *file, const char __user *buf,
 				size_t count, loff_t *ppos)
 {
@@ -1151,12 +1162,6 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf,
 		struct clear_refs_private cp = {
 			.type = type,
 		};
-		struct mm_walk clear_refs_walk = {
-			.pmd_entry = clear_refs_pte_range,
-			.test_walk = clear_refs_test_walk,
-			.mm = mm,
-			.private = &cp,
-		};
 
 		if (type == CLEAR_REFS_MM_HIWATER_RSS) {
 			if (down_write_killable(&mm->mmap_sem)) {
@@ -1217,7 +1222,8 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf,
 						0, NULL, mm, 0, -1UL);
 			mmu_notifier_invalidate_range_start(&range);
 		}
-		walk_page_range(0, mm->highest_vm_end, &clear_refs_walk);
+		walk_page_range(mm, 0, mm->highest_vm_end, &clear_refs_walk_ops,
+				&cp);
 		if (type == CLEAR_REFS_SOFT_DIRTY)
 			mmu_notifier_invalidate_range_end(&range);
 		tlb_finish_mmu(&tlb, 0, -1);
@@ -1489,8 +1495,16 @@ static int pagemap_hugetlb_range(pte_t *ptep, unsigned long hmask,
 
 	return err;
 }
+#else
+#define pagemap_hugetlb_range	NULL
 #endif /* HUGETLB_PAGE */
 
+static const struct mm_walk_ops pagemap_ops = {
+	.pmd_entry	= pagemap_pmd_range,
+	.pte_hole	= pagemap_pte_hole,
+	.hugetlb_entry	= pagemap_hugetlb_range,
+};
+
 /*
  * /proc/pid/pagemap - an array mapping virtual pages to pfns
  *
@@ -1522,7 +1536,6 @@ static ssize_t pagemap_read(struct file *file, char __user *buf,
 {
 	struct mm_struct *mm = file->private_data;
 	struct pagemapread pm;
-	struct mm_walk pagemap_walk = {};
 	unsigned long src;
 	unsigned long svpfn;
 	unsigned long start_vaddr;
@@ -1550,14 +1563,6 @@ static ssize_t pagemap_read(struct file *file, char __user *buf,
 	if (!pm.buffer)
 		goto out_mm;
 
-	pagemap_walk.pmd_entry = pagemap_pmd_range;
-	pagemap_walk.pte_hole = pagemap_pte_hole;
-#ifdef CONFIG_HUGETLB_PAGE
-	pagemap_walk.hugetlb_entry = pagemap_hugetlb_range;
-#endif
-	pagemap_walk.mm = mm;
-	pagemap_walk.private = &pm;
-
 	src = *ppos;
 	svpfn = src / PM_ENTRY_BYTES;
 	start_vaddr = svpfn << PAGE_SHIFT;
@@ -1586,7 +1591,7 @@ static ssize_t pagemap_read(struct file *file, char __user *buf,
 		ret = down_read_killable(&mm->mmap_sem);
 		if (ret)
 			goto out_free;
-		ret = walk_page_range(start_vaddr, end, &pagemap_walk);
+		ret = walk_page_range(mm, start_vaddr, end, &pagemap_ops, &pm);
 		up_read(&mm->mmap_sem);
 		start_vaddr = end;
 
@@ -1798,6 +1803,11 @@ static int gather_hugetlb_stats(pte_t *pte, unsigned long hmask,
 }
 #endif
 
+static const struct mm_walk_ops show_numa_ops = {
+	.hugetlb_entry = gather_hugetlb_stats,
+	.pmd_entry = gather_pte_stats,
+};
+
 /*
  * Display pages allocated per node and memory policy via /proc.
  */
@@ -1809,12 +1819,6 @@ static int show_numa_map(struct seq_file *m, void *v)
 	struct numa_maps *md = &numa_priv->md;
 	struct file *file = vma->vm_file;
 	struct mm_struct *mm = vma->vm_mm;
-	struct mm_walk walk = {
-		.hugetlb_entry = gather_hugetlb_stats,
-		.pmd_entry = gather_pte_stats,
-		.private = md,
-		.mm = mm,
-	};
 	struct mempolicy *pol;
 	char buffer[64];
 	int nid;
@@ -1848,7 +1852,7 @@ static int show_numa_map(struct seq_file *m, void *v)
 		seq_puts(m, " huge");
 
 	/* mmap_sem is held by m_start */
-	walk_page_vma(vma, &walk);
+	walk_page_vma(vma, &show_numa_ops, md);
 
 	if (!md->pages)
 		goto out;