[PATCHv3 2/2] mm: implement ->map_pages for page cache

From: Kirill A. Shutemov
Date: Thu Feb 27 2014 - 14:54:24 EST

filemap_map_pages() is generic implementation of ->map_pages() for
filesystems who uses page cache.

It should be safe to use filemap_map_pages() for ->map_pages() if
filesystem use filemap_fault() for ->fault().

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
fs/9p/vfs_file.c | 2 ++
fs/btrfs/file.c | 1 +
fs/cifs/file.c | 1 +
fs/ext4/file.c | 1 +
fs/f2fs/file.c | 1 +
fs/fuse/file.c | 1 +
fs/gfs2/file.c | 1 +
fs/nfs/file.c | 1 +
fs/nilfs2/file.c | 1 +
fs/ubifs/file.c | 1 +
fs/xfs/xfs_file.c | 1 +
include/linux/mm.h | 1 +
mm/filemap.c | 72 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
mm/nommu.c | 6 +++++
14 files changed, 91 insertions(+)

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 0165b8672f09..d1f0415bbfb1 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1993,6 +1993,7 @@ 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 755584684f6c..6d081de57fdb 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -3094,6 +3094,7 @@ 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 1a5073959f32..46e78f8a133f 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 77bcc303c3ae..da99a76668f8 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -1940,6 +1940,7 @@ 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 efc078f0ee4e..2739f3c3bb8f 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 64b48eade91d..b2be204e16ca 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -1465,6 +1465,7 @@ 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 aed92cb17127..7c4bfb725e63 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1818,6 +1818,7 @@ extern void truncate_inode_pages_range(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 7a13f6ac5421..1bc12a96060d 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
@@ -1726,6 +1727,76 @@ 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 (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 (page->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;
@@ -1755,6 +1826,7 @@ 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 8740213b1647..ce401e37e29f 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)
{
--
1.9.0

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