From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file

---
 kernel/mm/mincore.c |   48 ++++++++++++++++--------------------------------
 1 files changed, 16 insertions(+), 32 deletions(-)

diff --git a/kernel/mm/mincore.c b/kernel/mm/mincore.c
index 7eb1491..02db1a8 100644
--- a/kernel/mm/mincore.c
+++ b/kernel/mm/mincore.c
@@ -10,16 +10,16 @@
  */
 #include <linux/pagemap.h>
 #include <linux/gfp.h>
-#include <linux/mm.h>
+#include <linux/pagewalk.h>
 #include <linux/mman.h>
 #include <linux/syscalls.h>
 #include <linux/swap.h>
 #include <linux/swapops.h>
 #include <linux/shmem_fs.h>
 #include <linux/hugetlb.h>
+#include <linux/pgtable.h>
 
 #include <linux/uaccess.h>
-#include <asm/pgtable.h>
 
 static int mincore_hugetlb(pte_t *pte, unsigned long hmask, unsigned long addr,
 			unsigned long end, struct mm_walk *walk)
@@ -48,7 +48,7 @@
  * and is up to date; i.e. that no page-in operation would be required
  * at this time if an application were to map and access this page.
  */
-static unsigned char mincore_page(struct address_space *mapping, pgoff_t pgoff)
+static unsigned char mincore_page(struct address_space *mapping, pgoff_t index)
 {
 	unsigned char present = 0;
 	struct page *page;
@@ -59,23 +59,7 @@
 	 * any other file mapping (ie. marked !present and faulted in with
 	 * tmpfs's .fault). So swapped out tmpfs mappings are tested here.
 	 */
-#ifdef CONFIG_SWAP
-	if (shmem_mapping(mapping)) {
-		page = find_get_entry(mapping, pgoff);
-		/*
-		 * shmem/tmpfs may return swap: account for swapcache
-		 * page too.
-		 */
-		if (radix_tree_exceptional_entry(page)) {
-			swp_entry_t swp = radix_to_swp_entry(page);
-			page = find_get_page(swap_address_space(swp),
-					     swp_offset(swp));
-		}
-	} else
-		page = find_get_page(mapping, pgoff);
-#else
-	page = find_get_page(mapping, pgoff);
-#endif
+	page = find_get_incore_page(mapping, index);
 	if (page) {
 		present = PageUptodate(page);
 		put_page(page);
@@ -104,6 +88,7 @@
 }
 
 static int mincore_unmapped_range(unsigned long addr, unsigned long end,
+				   __always_unused int depth,
 				   struct mm_walk *walk)
 {
 	walk->private += __mincore_unmapped_range(addr, end,
@@ -185,6 +170,12 @@
 		inode_permission(file_inode(vma->vm_file), MAY_WRITE) == 0;
 }
 
+static const struct mm_walk_ops mincore_walk_ops = {
+	.pmd_entry		= mincore_pte_range,
+	.pte_hole		= mincore_unmapped_range,
+	.hugetlb_entry		= mincore_hugetlb,
+};
+
 /*
  * Do a chunk of "sys_mincore()". We've already checked
  * all the arguments, we hold the mmap semaphore: we should
@@ -195,12 +186,6 @@
 	struct vm_area_struct *vma;
 	unsigned long end;
 	int err;
-	struct mm_walk mincore_walk = {
-		.pmd_entry = mincore_pte_range,
-		.pte_hole = mincore_unmapped_range,
-		.hugetlb_entry = mincore_hugetlb,
-		.private = vec,
-	};
 
 	vma = find_vma(current->mm, addr);
 	if (!vma || addr < vma->vm_start)
@@ -211,8 +196,7 @@
 		memset(vec, 1, pages);
 		return pages;
 	}
-	mincore_walk.mm = vma->vm_mm;
-	err = walk_page_range(addr, end, &mincore_walk);
+	err = walk_page_range(vma->vm_mm, addr, end, &mincore_walk_ops, vec);
 	if (err < 0)
 		return err;
 	return (end - addr) >> PAGE_SHIFT;
@@ -256,14 +240,14 @@
 		return -EINVAL;
 
 	/* ..and we need to be passed a valid user-space range */
-	if (!access_ok(VERIFY_READ, (void __user *) start, len))
+	if (!access_ok((void __user *) start, len))
 		return -ENOMEM;
 
 	/* This also avoids any overflows on PAGE_ALIGN */
 	pages = len >> PAGE_SHIFT;
 	pages += (offset_in_page(len)) != 0;
 
-	if (!access_ok(VERIFY_WRITE, vec, pages))
+	if (!access_ok(vec, pages))
 		return -EFAULT;
 
 	tmp = (void *) __get_free_page(GFP_USER);
@@ -276,9 +260,9 @@
 		 * Do at most PAGE_SIZE entries per iteration, due to
 		 * the temporary buffer size.
 		 */
-		down_read(&current->mm->mmap_sem);
+		mmap_read_lock(current->mm);
 		retval = do_mincore(start, min(pages, PAGE_SIZE), tmp);
-		up_read(&current->mm->mmap_sem);
+		mmap_read_unlock(current->mm);
 
 		if (retval <= 0)
 			break;

--
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