mm: split out a new pagewalk.h header from mm.h
Add a new header for the two handful of users of the walk_page_range /
walk_page_vma interface instead of polluting all users of mm.h with it.
Link: https://lore.kernel.org/r/20190828141955.22210-2-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
diff --git a/include/linux/pagewalk.h b/include/linux/pagewalk.h
new file mode 100644
index 0000000..df278a9
--- /dev/null
+++ b/include/linux/pagewalk.h
@@ -0,0 +1,54 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_PAGEWALK_H
+#define _LINUX_PAGEWALK_H
+
+#include <linux/mm.h>
+
+/**
+ * mm_walk - callbacks for walk_page_range
+ * @pud_entry: if set, called for each non-empty PUD (2nd-level) entry
+ * this handler should only handle pud_trans_huge() puds.
+ * the pmd_entry or pte_entry callbacks will be used for
+ * regular PUDs.
+ * @pmd_entry: if set, called for each non-empty PMD (3rd-level) entry
+ * this handler is required to be able to handle
+ * pmd_trans_huge() pmds. They may simply choose to
+ * split_huge_page() instead of handling it explicitly.
+ * @pte_entry: if set, called for each non-empty PTE (4th-level) entry
+ * @pte_hole: if set, called for each hole at all levels
+ * @hugetlb_entry: if set, called for each hugetlb entry
+ * @test_walk: caller specific callback function to determine whether
+ * we walk over the current vma or not. Returning 0
+ * value means "do page table walk over the current vma,"
+ * and a negative one means "abort current page table walk
+ * right now." 1 means "skip the current vma."
+ * @mm: mm_struct representing the target process of page table walk
+ * @vma: vma currently walked (NULL if walking outside vmas)
+ * @private: private data for callbacks' usage
+ *
+ * (see the comment on walk_page_range() for more details)
+ */
+struct mm_walk {
+ int (*pud_entry)(pud_t *pud, unsigned long addr,
+ unsigned long next, struct mm_walk *walk);
+ int (*pmd_entry)(pmd_t *pmd, unsigned long addr,
+ unsigned long next, struct mm_walk *walk);
+ int (*pte_entry)(pte_t *pte, unsigned long addr,
+ unsigned long next, struct mm_walk *walk);
+ int (*pte_hole)(unsigned long addr, unsigned long next,
+ struct mm_walk *walk);
+ int (*hugetlb_entry)(pte_t *pte, unsigned long hmask,
+ unsigned long addr, unsigned long next,
+ struct mm_walk *walk);
+ int (*test_walk)(unsigned long addr, unsigned long next,
+ struct mm_walk *walk);
+ struct mm_struct *mm;
+ struct vm_area_struct *vma;
+ void *private;
+};
+
+int walk_page_range(unsigned long addr, unsigned long end,
+ struct mm_walk *walk);
+int walk_page_vma(struct vm_area_struct *vma, struct mm_walk *walk);
+
+#endif /* _LINUX_PAGEWALK_H */