14 files changed, 93 insertions, 0 deletions

diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c
index a16b0ff497ca..d8223209d4b1 100644
--- a/fs/9p/vfs_file.c
+++ b/fs/9p/vfs_file.c
@@ -832,6 +832,7 @@ static void v9fs_mmap_vm_close(struct vm_area_struct *vma)
 
 static const struct vm_operations_struct v9fs_file_vm_ops = {
         .fault = filemap_fault,
+        .map_pages = filemap_map_pages,
         .page_mkwrite = v9fs_vm_page_mkwrite,
         .remap_pages = generic_file_remap_pages,
 };
@@ -839,6 +840,7 @@ static const struct vm_operations_struct v9fs_file_vm_ops = {
 static const struct vm_operations_struct v9fs_mmap_file_vm_ops = {
         .close = v9fs_mmap_vm_close,
         .fault = filemap_fault,
+        .map_pages = filemap_map_pages,
         .page_mkwrite = v9fs_vm_page_mkwrite,
         .remap_pages = generic_file_remap_pages,
 };
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index e1ffb1e22898..c660527af838 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -2025,6 +2025,7 @@ out:
 
 static const struct vm_operations_struct btrfs_file_vm_ops = {
         .fault          = filemap_fault,
+        .map_pages      = filemap_map_pages,
         .page_mkwrite   = btrfs_page_mkwrite,
         .remap_pages    = generic_file_remap_pages,
 };
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 834fce759d80..216d7e99f921 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -3113,6 +3113,7 @@ cifs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
 
 static struct vm_operations_struct cifs_file_vm_ops = {
         .fault = filemap_fault,
+        .map_pages = filemap_map_pages,
         .page_mkwrite = cifs_page_mkwrite,
         .remap_pages = generic_file_remap_pages,
 };
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 6db7f7db7777..4e508fc83dcf 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -200,6 +200,7 @@ ext4_file_write(struct kiocb *iocb, const struct iovec *iov,
 
 static const struct vm_operations_struct ext4_file_vm_ops = {
         .fault          = filemap_fault,
+        .map_pages      = filemap_map_pages,
         .page_mkwrite   = ext4_page_mkwrite,
         .remap_pages    = generic_file_remap_pages,
 };
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 0dfcef53a6ed..129a3bdb05ca 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -84,6 +84,7 @@ out:
 
 static const struct vm_operations_struct f2fs_file_vm_ops = {
         .fault          = filemap_fault,
+        .map_pages      = filemap_map_pages,
         .page_mkwrite   = f2fs_vm_page_mkwrite,
         .remap_pages    = generic_file_remap_pages,
 };
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 65df7d8be4f5..48992cac714b 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -2117,6 +2117,7 @@ static int fuse_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
 static const struct vm_operations_struct fuse_file_vm_ops = {
         .close          = fuse_vma_close,
         .fault          = filemap_fault,
+        .map_pages      = filemap_map_pages,
         .page_mkwrite   = fuse_page_mkwrite,
         .remap_pages    = generic_file_remap_pages,
 };
diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
index 6c794085abac..80d67253623c 100644
--- a/fs/gfs2/file.c
+++ b/fs/gfs2/file.c
@@ -494,6 +494,7 @@ out:
 
 static const struct vm_operations_struct gfs2_vm_ops = {
         .fault = filemap_fault,
+        .map_pages = filemap_map_pages,
         .page_mkwrite = gfs2_page_mkwrite,
         .remap_pages = generic_file_remap_pages,
 };
diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index 5bb790a69c71..284ca901fe16 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -617,6 +617,7 @@ out:
 
 static const struct vm_operations_struct nfs_file_vm_ops = {
         .fault = filemap_fault,
+        .map_pages = filemap_map_pages,
         .page_mkwrite = nfs_vm_page_mkwrite,
         .remap_pages = generic_file_remap_pages,
 };
diff --git a/fs/nilfs2/file.c b/fs/nilfs2/file.c
index 08fdb77852ac..f3a82fbcae02 100644
--- a/fs/nilfs2/file.c
+++ b/fs/nilfs2/file.c
@@ -134,6 +134,7 @@ static int nilfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
 
 static const struct vm_operations_struct nilfs_file_vm_ops = {
         .fault          = filemap_fault,
+        .map_pages      = filemap_map_pages,
         .page_mkwrite   = nilfs_page_mkwrite,
         .remap_pages    = generic_file_remap_pages,
 };
diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c
index 123c79b7261e..4f34dbae823d 100644
--- a/fs/ubifs/file.c
+++ b/fs/ubifs/file.c
@@ -1538,6 +1538,7 @@ out_unlock:
 
 static const struct vm_operations_struct ubifs_file_vm_ops = {
         .fault        = filemap_fault,
+        .map_pages = filemap_map_pages,
         .page_mkwrite = ubifs_vm_page_mkwrite,
         .remap_pages = generic_file_remap_pages,
 };
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index f7abff8c16ca..003c0051b62f 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -1483,6 +1483,7 @@ const struct file_operations xfs_dir_file_operations = {
 
 static const struct vm_operations_struct xfs_file_vm_ops = {
         .fault          = filemap_fault,
+        .map_pages      = filemap_map_pages,
         .page_mkwrite   = xfs_vm_page_mkwrite,
         .remap_pages    = generic_file_remap_pages,
 };
diff --git a/include/linux/mm.h b/include/linux/mm.h
index f710d32291e8..9132faed1a41 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1847,6 +1847,7 @@ extern void truncate_inode_pages_final(struct address_space *);
 
 /* generic vm_area_ops exported for stackable file systems */
 extern int filemap_fault(struct vm_area_struct *, struct vm_fault *);
+extern void filemap_map_pages(struct vm_area_struct *vma, struct vm_fault *vmf);
 extern int filemap_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf);
 
 /* mm/page-writeback.c */
diff --git a/mm/filemap.c b/mm/filemap.c
index 21781f1fe52b..3f9b5fbb623f 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -33,6 +33,7 @@
 #include <linux/hardirq.h> /* for BUG_ON(!in_atomic()) only */
 #include <linux/memcontrol.h>
 #include <linux/cleancache.h>
+#include <linux/rmap.h>
 #include "internal.h"
 
 #define CREATE_TRACE_POINTS
@@ -2064,6 +2065,78 @@ page_not_uptodate:
 }
 EXPORT_SYMBOL(filemap_fault);
 
+void filemap_map_pages(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+        struct radix_tree_iter iter;
+        void **slot;
+        struct file *file = vma->vm_file;
+        struct address_space *mapping = file->f_mapping;
+        loff_t size;
+        struct page *page;
+        unsigned long address = (unsigned long) vmf->virtual_address;
+        unsigned long addr;
+        pte_t *pte;
+
+        rcu_read_lock();
+        radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, vmf->pgoff) {
+                if (iter.index > vmf->max_pgoff)
+                        break;
+repeat:
+                page = radix_tree_deref_slot(slot);
+                if (unlikely(!page))
+                        goto next;
+                if (radix_tree_exception(page)) {
+                        if (radix_tree_deref_retry(page))
+                                break;
+                        else
+                                goto next;
+                }
+
+                if (!page_cache_get_speculative(page))
+                        goto repeat;
+
+                /* Has the page moved? */
+                if (unlikely(page != *slot)) {
+                        page_cache_release(page);
+                        goto repeat;
+                }
+
+                if (!PageUptodate(page) ||
+                                PageReadahead(page) ||
+                                PageHWPoison(page))
+                        goto skip;
+                if (!trylock_page(page))
+                        goto skip;
+
+                if (page->mapping != mapping || !PageUptodate(page))
+                        goto unlock;
+
+                size = i_size_read(mapping->host) + PAGE_CACHE_SIZE - 1;
+                if (page->index >= size >> PAGE_CACHE_SHIFT)
+                        goto unlock;
+
+                pte = vmf->pte + page->index - vmf->pgoff;
+                if (!pte_none(*pte))
+                        goto unlock;
+
+                if (file->f_ra.mmap_miss > 0)
+                        file->f_ra.mmap_miss--;
+                addr = address + (page->index - vmf->pgoff) * PAGE_SIZE;
+                do_set_pte(vma, addr, page, pte, false, false);
+                unlock_page(page);
+                goto next;
+unlock:
+                unlock_page(page);
+skip:
+                page_cache_release(page);
+next:
+                if (iter.index == vmf->max_pgoff)
+                        break;
+        }
+        rcu_read_unlock();
+}
+EXPORT_SYMBOL(filemap_map_pages);
+
 int filemap_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
 {
         struct page *page = vmf->page;
@@ -2093,6 +2166,7 @@ EXPORT_SYMBOL(filemap_page_mkwrite);
 
 const struct vm_operations_struct generic_file_vm_ops = {
         .fault          = filemap_fault,
+        .map_pages      = filemap_map_pages,
         .page_mkwrite   = filemap_page_mkwrite,
         .remap_pages    = generic_file_remap_pages,
 };
diff --git a/mm/nommu.c b/mm/nommu.c
index a554e5a451cd..e19482533ce3 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1985,6 +1985,12 @@ int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 }
 EXPORT_SYMBOL(filemap_fault);
 
+void filemap_map_pages(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+        BUG();
+}
+EXPORT_SYMBOL(filemap_map_pages);
+
 int generic_file_remap_pages(struct vm_area_struct *vma, unsigned long addr,
                              unsigned long size, pgoff_t pgoff)
 {