mm: make read_cache_page synchronous

Ensure pages are uptodate after returning from read_cache_page, which allows
us to cut out most of the filesystem-internal PageUptodate calls.

I didn't have a great look down the call chains, but this appears to fixes 7
possible use-before uptodate in hfs, 2 in hfsplus, 1 in jfs, a few in
ecryptfs, 1 in jffs2, and a possible cleared data overwritten with readpage in
block2mtd.  All depending on whether the filler is async and/or can return
with a !uptodate page.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

24 files changed, 71 insertions, 146 deletions

diff --git a/drivers/mtd/devices/block2mtd.c b/drivers/mtd/devices/block2mtd.c
index ce47544dc120..fc4cc8ba9e29 100644
--- a/drivers/mtd/devices/block2mtd.c
+++ b/drivers/mtd/devices/block2mtd.c
@@ -40,13 +40,11 @@ struct block2mtd_dev {
 static LIST_HEAD(blkmtd_device_list);
 
 
-static struct page* page_read(struct address_space *mapping, int index)
+static struct page *page_read(struct address_space *mapping, int index)
 {
-        filler_t *filler = (filler_t*)mapping->a_ops->readpage;
-        return read_cache_page(mapping, index, filler, NULL);
+        return read_mapping_page(mapping, index, NULL);
 }
 
-
 /* erase a specified part of the device */
 static int _block2mtd_erase(struct block2mtd_dev *dev, loff_t to, size_t len)
 {
diff --git a/fs/afs/dir.c b/fs/afs/dir.c
index dac5b990c0cd..0c1e902f17a3 100644
--- a/fs/afs/dir.c
+++ b/fs/afs/dir.c
@@ -194,10 +194,7 @@ static struct page *afs_dir_get_page(struct inode *dir, unsigned long index,
 
         page = read_mapping_page(dir->i_mapping, index, &file);
         if (!IS_ERR(page)) {
-                wait_on_page_locked(page);
                 kmap(page);
-                if (!PageUptodate(page))
-                        goto fail;
                 if (!PageChecked(page))
                         afs_dir_check_page(dir, page);
                 if (PageError(page))
diff --git a/fs/afs/mntpt.c b/fs/afs/mntpt.c
index b905ae37f912..034fcfd4e330 100644
--- a/fs/afs/mntpt.c
+++ b/fs/afs/mntpt.c
@@ -68,13 +68,11 @@ int afs_mntpt_check_symlink(struct afs_vnode *vnode, struct key *key)
         }
 
         ret = -EIO;
-        wait_on_page_locked(page);
-        buf = kmap(page);
-        if (!PageUptodate(page))
-                goto out_free;
         if (PageError(page))
                 goto out_free;
 
+        buf = kmap(page);
+
         /* examine the symlink's contents */
         size = vnode->status.size;
         _debug("symlink to %*.*s", (int) size, (int) size, buf);
@@ -91,8 +89,8 @@ int afs_mntpt_check_symlink(struct afs_vnode *vnode, struct key *key)
 
         ret = 0;
 
-out_free:
         kunmap(page);
+out_free:
         page_cache_release(page);
 out:
         _leave(" = %d", ret);
@@ -171,8 +169,7 @@ static struct vfsmount *afs_mntpt_do_automount(struct dentry *mntpt)
         }
 
         ret = -EIO;
-        wait_on_page_locked(page);
-        if (!PageUptodate(page) || PageError(page))
+        if (PageError(page))
                 goto error;
 
         buf = kmap(page);
diff --git a/fs/cramfs/inode.c b/fs/cramfs/inode.c
index facd0c89be8f..3d194a2be3f5 100644
--- a/fs/cramfs/inode.c
+++ b/fs/cramfs/inode.c
@@ -180,7 +180,8 @@ static void *cramfs_read(struct super_block *sb, unsigned int offset, unsigned i
                 struct page *page = NULL;
 
                 if (blocknr + i < devsize) {
-                        page = read_mapping_page(mapping, blocknr + i, NULL);
+                        page = read_mapping_page_async(mapping, blocknr + i,
+                                                                        NULL);
                         /* synchronous error? */
                         if (IS_ERR(page))
                                 page = NULL;
diff --git a/fs/ecryptfs/mmap.c b/fs/ecryptfs/mmap.c
index b731b09499cb..0770c4b66f53 100644
--- a/fs/ecryptfs/mmap.c
+++ b/fs/ecryptfs/mmap.c
@@ -46,7 +46,6 @@ struct kmem_cache *ecryptfs_lower_page_cache;
  */
 static struct page *ecryptfs_get1page(struct file *file, int index)
 {
-        struct page *page;
         struct dentry *dentry;
         struct inode *inode;
         struct address_space *mapping;
@@ -54,14 +53,7 @@ static struct page *ecryptfs_get1page(struct file *file, int index)
         dentry = file->f_path.dentry;
         inode = dentry->d_inode;
         mapping = inode->i_mapping;
-        page = read_cache_page(mapping, index,
-                               (filler_t *)mapping->a_ops->readpage,
-                               (void *)file);
-        if (IS_ERR(page))
-                goto out;
-        wait_on_page_locked(page);
-out:
-        return page;
+        return read_mapping_page(mapping, index, (void *)file);
 }
 
 static
@@ -233,7 +225,6 @@ int ecryptfs_do_readpage(struct file *file, struct page *page,
                 ecryptfs_printk(KERN_ERR, "Error reading from page cache\n");
                 goto out;
         }
-        wait_on_page_locked(lower_page);
         page_data = kmap_atomic(page, KM_USER0);
         lower_page_data = kmap_atomic(lower_page, KM_USER1);
         memcpy(page_data, lower_page_data, PAGE_CACHE_SIZE);
diff --git a/fs/ext2/dir.c b/fs/ext2/dir.c
index e89bfc8cf957..1d1e7e30d70e 100644
--- a/fs/ext2/dir.c
+++ b/fs/ext2/dir.c
@@ -161,10 +161,7 @@ static struct page * ext2_get_page(struct inode *dir, unsigned long n)
         struct address_space *mapping = dir->i_mapping;
         struct page *page = read_mapping_page(mapping, n, NULL);
         if (!IS_ERR(page)) {
-                wait_on_page_locked(page);
                 kmap(page);
-                if (!PageUptodate(page))
-                        goto fail;
                 if (!PageChecked(page))
                         ext2_check_page(page);
                 if (PageError(page))
diff --git a/fs/freevxfs/vxfs_subr.c b/fs/freevxfs/vxfs_subr.c
index decac62efe57..ed8f0b0dd880 100644
--- a/fs/freevxfs/vxfs_subr.c
+++ b/fs/freevxfs/vxfs_subr.c
@@ -74,10 +74,7 @@ vxfs_get_page(struct address_space *mapping, u_long n)
         pp = read_mapping_page(mapping, n, NULL);
 
         if (!IS_ERR(pp)) {
-                wait_on_page_locked(pp);
                 kmap(pp);
-                if (!PageUptodate(pp))
-                        goto fail;
                 /** if (!PageChecked(pp)) **/
                         /** vxfs_check_page(pp); **/
                 if (PageError(pp))
diff --git a/fs/minix/dir.c b/fs/minix/dir.c
index cb4cb571fddf..e207cbe70951 100644
--- a/fs/minix/dir.c
+++ b/fs/minix/dir.c
@@ -65,7 +65,6 @@ static struct page * dir_get_page(struct inode *dir, unsigned long n)
         struct address_space *mapping = dir->i_mapping;
         struct page *page = read_mapping_page(mapping, n, NULL);
         if (!IS_ERR(page)) {
-                wait_on_page_locked(page);
                 kmap(page);
                 if (!PageUptodate(page))
                         goto fail;
diff --git a/fs/namei.c b/fs/namei.c
index 880052cadbcd..94b2f60aec22 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2671,19 +2671,9 @@ static char *page_getlink(struct dentry * dentry, struct page **ppage)
         struct address_space *mapping = dentry->d_inode->i_mapping;
         page = read_mapping_page(mapping, 0, NULL);
         if (IS_ERR(page))
-                goto sync_fail;
-        wait_on_page_locked(page);
-        if (!PageUptodate(page))
-                goto async_fail;
+                return (char*)page;
         *ppage = page;
         return kmap(page);
-
-async_fail:
-        page_cache_release(page);
-        return ERR_PTR(-EIO);
-
-sync_fail:
-        return (char*)page;
 }
 
 int page_readlink(struct dentry *dentry, char __user *buffer, int buflen)
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index e59fd31c9a22..625d8e5fb39d 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -334,8 +334,6 @@ int find_dirent_page(nfs_readdir_descriptor_t *desc)
                 status = PTR_ERR(page);
                 goto out;
         }
-        if (!PageUptodate(page))
-                goto read_error;
 
         /* NOTE: Someone else may have changed the READDIRPLUS flag */
         desc->page = page;
@@ -349,9 +347,6 @@ int find_dirent_page(nfs_readdir_descriptor_t *desc)
  out:
         dfprintk(DIRCACHE, "NFS: %s: returns %d\n", __FUNCTION__, status);
         return status;
- read_error:
-        page_cache_release(page);
-        return -EIO;
 }
 
 /*
diff --git a/fs/nfs/symlink.c b/fs/nfs/symlink.c
index f4a0548b9ce8..bc2821331c29 100644
--- a/fs/nfs/symlink.c
+++ b/fs/nfs/symlink.c
@@ -61,15 +61,9 @@ static void *nfs_follow_link(struct dentry *dentry, struct nameidata *nd)
                 err = page;
                 goto read_failed;
         }
-        if (!PageUptodate(page)) {
-                err = ERR_PTR(-EIO);
-                goto getlink_read_error;
-        }
         nd_set_link(nd, kmap(page));
         return page;
 
-getlink_read_error:
-        page_cache_release(page);
 read_failed:
         nd_set_link(nd, err);
         return NULL;
diff --git a/fs/ntfs/aops.h b/fs/ntfs/aops.h
index 9393f4b1e298..caecc58f529c 100644
--- a/fs/ntfs/aops.h
+++ b/fs/ntfs/aops.h
@@ -89,9 +89,8 @@ static inline struct page *ntfs_map_page(struct address_space *mapping,
         struct page *page = read_mapping_page(mapping, index, NULL);
 
         if (!IS_ERR(page)) {
-                wait_on_page_locked(page);
                 kmap(page);
-                if (PageUptodate(page) && !PageError(page))
+                if (!PageError(page))
                         return page;
                 ntfs_unmap_page(page);
                 return ERR_PTR(-EIO);
diff --git a/fs/ntfs/attrib.c b/fs/ntfs/attrib.c
index 7659cc192995..1c08fefe487a 100644
--- a/fs/ntfs/attrib.c
+++ b/fs/ntfs/attrib.c
@@ -2532,14 +2532,7 @@ int ntfs_attr_set(ntfs_inode *ni, const s64 ofs, const s64 cnt, const u8 val)
                 page = read_mapping_page(mapping, idx, NULL);
                 if (IS_ERR(page)) {
                         ntfs_error(vol->sb, "Failed to read first partial "
-                                        "page (sync error, index 0x%lx).", idx);
-                        return PTR_ERR(page);
-                }
-                wait_on_page_locked(page);
-                if (unlikely(!PageUptodate(page))) {
-                        ntfs_error(vol->sb, "Failed to read first partial page "
-                                        "(async error, index 0x%lx).", idx);
-                        page_cache_release(page);
+                                        "page (error, index 0x%lx).", idx);
                         return PTR_ERR(page);
                 }
                 /*
@@ -2602,14 +2595,7 @@ int ntfs_attr_set(ntfs_inode *ni, const s64 ofs, const s64 cnt, const u8 val)
                 page = read_mapping_page(mapping, idx, NULL);
                 if (IS_ERR(page)) {
                         ntfs_error(vol->sb, "Failed to read last partial page "
-                                        "(sync error, index 0x%lx).", idx);
-                        return PTR_ERR(page);
-                }
-                wait_on_page_locked(page);
-                if (unlikely(!PageUptodate(page))) {
-                        ntfs_error(vol->sb, "Failed to read last partial page "
-                                        "(async error, index 0x%lx).", idx);
-                        page_cache_release(page);
+                                        "(error, index 0x%lx).", idx);
                         return PTR_ERR(page);
                 }
                 kaddr = kmap_atomic(page, KM_USER0);
diff --git a/fs/ntfs/file.c b/fs/ntfs/file.c
index d69c4595ccd0..dbbac5593106 100644
--- a/fs/ntfs/file.c
+++ b/fs/ntfs/file.c
@@ -236,8 +236,7 @@ do_non_resident_extend:
                         err = PTR_ERR(page);
                         goto init_err_out;
                 }
-                wait_on_page_locked(page);
-                if (unlikely(!PageUptodate(page) || PageError(page))) {
+                if (unlikely(PageError(page))) {
                         page_cache_release(page);
                         err = -EIO;
                         goto init_err_out;
diff --git a/fs/ntfs/super.c b/fs/ntfs/super.c
index 1594c90b7164..2ddde534db0a 100644
--- a/fs/ntfs/super.c
+++ b/fs/ntfs/super.c
@@ -2471,7 +2471,6 @@ static s64 get_nr_free_clusters(ntfs_volume *vol)
         s64 nr_free = vol->nr_clusters;
         u32 *kaddr;
         struct address_space *mapping = vol->lcnbmp_ino->i_mapping;
-        filler_t *readpage = (filler_t*)mapping->a_ops->readpage;
         struct page *page;
         pgoff_t index, max_index;
 
@@ -2494,24 +2493,14 @@ static s64 get_nr_free_clusters(ntfs_volume *vol)
                  * Read the page from page cache, getting it from backing store
                  * if necessary, and increment the use count.
                  */
-                page = read_cache_page(mapping, index, (filler_t*)readpage,
-                                NULL);
+                page = read_mapping_page(mapping, index, NULL);
                 /* Ignore pages which errored synchronously. */
                 if (IS_ERR(page)) {
-                        ntfs_debug("Sync read_cache_page() error. Skipping "
+                        ntfs_debug("read_mapping_page() error. Skipping "
                                         "page (index 0x%lx).", index);
                         nr_free -= PAGE_CACHE_SIZE * 8;
                         continue;
                 }
-                wait_on_page_locked(page);
-                /* Ignore pages which errored asynchronously. */
-                if (!PageUptodate(page)) {
-                        ntfs_debug("Async read_cache_page() error. Skipping "
-                                        "page (index 0x%lx).", index);
-                        page_cache_release(page);
-                        nr_free -= PAGE_CACHE_SIZE * 8;
-                        continue;
-                }
                 kaddr = (u32*)kmap_atomic(page, KM_USER0);
                 /*
                  * For each 4 bytes, subtract the number of set bits. If this
@@ -2562,7 +2551,6 @@ static unsigned long __get_nr_free_mft_records(ntfs_volume *vol,
 {
         u32 *kaddr;
         struct address_space *mapping = vol->mftbmp_ino->i_mapping;
-        filler_t *readpage = (filler_t*)mapping->a_ops->readpage;
         struct page *page;
         pgoff_t index;
 
@@ -2576,21 +2564,11 @@ static unsigned long __get_nr_free_mft_records(ntfs_volume *vol,
                  * Read the page from page cache, getting it from backing store
                  * if necessary, and increment the use count.
                  */
-                page = read_cache_page(mapping, index, (filler_t*)readpage,
-                                NULL);
+                page = read_mapping_page(mapping, index, NULL);
                 /* Ignore pages which errored synchronously. */
                 if (IS_ERR(page)) {
-                        ntfs_debug("Sync read_cache_page() error. Skipping "
-                                        "page (index 0x%lx).", index);
-                        nr_free -= PAGE_CACHE_SIZE * 8;
-                        continue;
-                }
-                wait_on_page_locked(page);
-                /* Ignore pages which errored asynchronously. */
-                if (!PageUptodate(page)) {
-                        ntfs_debug("Async read_cache_page() error. Skipping "
+                        ntfs_debug("read_mapping_page() error. Skipping "
                                         "page (index 0x%lx).", index);
-                        page_cache_release(page);
                         nr_free -= PAGE_CACHE_SIZE * 8;
                         continue;
                 }
diff --git a/fs/ocfs2/symlink.c b/fs/ocfs2/symlink.c
index 40dc1a51f4a9..7134007ba22f 100644
--- a/fs/ocfs2/symlink.c
+++ b/fs/ocfs2/symlink.c
@@ -67,16 +67,9 @@ static char *ocfs2_page_getlink(struct dentry * dentry,
         page = read_mapping_page(mapping, 0, NULL);
         if (IS_ERR(page))
                 goto sync_fail;
-        wait_on_page_locked(page);
-        if (!PageUptodate(page))
-                goto async_fail;
         *ppage = page;
         return kmap(page);
 
-async_fail:
-        page_cache_release(page);
-        return ERR_PTR(-EIO);
-
 sync_fail:
         return (char*)page;
 }
diff --git a/fs/partitions/check.c b/fs/partitions/check.c
index f01572fca02f..6b9dae3f0e6c 100644
--- a/fs/partitions/check.c
+++ b/fs/partitions/check.c
@@ -569,9 +569,6 @@ unsigned char *read_dev_sector(struct block_device *bdev, sector_t n, Sector *p)
         page = read_mapping_page(mapping, (pgoff_t)(n >> (PAGE_CACHE_SHIFT-9)),
                                  NULL);
         if (!IS_ERR(page)) {
-                wait_on_page_locked(page);
-                if (!PageUptodate(page))
-                        goto fail;
                 if (PageError(page))
                         goto fail;
                 p->v = page;
diff --git a/fs/reiserfs/xattr.c b/fs/reiserfs/xattr.c
index 2cac56210e2b..bf6e58214538 100644
--- a/fs/reiserfs/xattr.c
+++ b/fs/reiserfs/xattr.c
@@ -410,11 +410,7 @@ static struct page *reiserfs_get_page(struct inode *dir, unsigned long n)
         mapping_set_gfp_mask(mapping, GFP_NOFS);
         page = read_mapping_page(mapping, n, NULL);
         if (!IS_ERR(page)) {
-                wait_on_page_locked(page);
                 kmap(page);
-                if (!PageUptodate(page))
-                        goto fail;
-
                 if (PageError(page))
                         goto fail;
         }
diff --git a/fs/sysv/dir.c b/fs/sysv/dir.c
index ebf7007fa161..e566b387fcf9 100644
--- a/fs/sysv/dir.c
+++ b/fs/sysv/dir.c
@@ -54,17 +54,9 @@ static struct page * dir_get_page(struct inode *dir, unsigned long n)
 {
         struct address_space *mapping = dir->i_mapping;
         struct page *page = read_mapping_page(mapping, n, NULL);
-        if (!IS_ERR(page)) {
-                wait_on_page_locked(page);
+        if (!IS_ERR(page))
                 kmap(page);
-                if (!PageUptodate(page))
-                        goto fail;
-        }
         return page;
-
-fail:
-        dir_put_page(page);
-        return ERR_PTR(-EIO);
 }
 
 static int sysv_readdir(struct file * filp, void * dirent, filldir_t filldir)
diff --git a/fs/ufs/dir.c b/fs/ufs/dir.c
index 4890ddf1518e..4fb8b2e077ee 100644
--- a/fs/ufs/dir.c
+++ b/fs/ufs/dir.c
@@ -180,13 +180,9 @@ fail:
 static struct page *ufs_get_page(struct inode *dir, unsigned long n)
 {
         struct address_space *mapping = dir->i_mapping;
-        struct page *page = read_cache_page(mapping, n,
-                                (filler_t*)mapping->a_ops->readpage, NULL);
+        struct page *page = read_mapping_page(mapping, n, NULL);
         if (!IS_ERR(page)) {
-                wait_on_page_locked(page);
                 kmap(page);
-                if (!PageUptodate(page))
-                        goto fail;
                 if (!PageChecked(page))
                         ufs_check_page(page);
                 if (PageError(page))
diff --git a/fs/ufs/util.c b/fs/ufs/util.c
index 17437574f79c..84357f1ff0ec 100644
--- a/fs/ufs/util.c
+++ b/fs/ufs/util.c
@@ -251,13 +251,11 @@ struct page *ufs_get_locked_page(struct address_space *mapping,
 
         page = find_lock_page(mapping, index);
         if (!page) {
-                page = read_cache_page(mapping, index,
-                                       (filler_t*)mapping->a_ops->readpage,
-                                       NULL);
+                page = read_mapping_page(mapping, index, NULL);
 
                 if (IS_ERR(page)) {
                         printk(KERN_ERR "ufs_change_blocknr: "
-                               "read_cache_page error: ino %lu, index: %lu\n",
+                               "read_mapping_page error: ino %lu, index: %lu\n",
                                mapping->host->i_ino, index);
                         goto out;
                 }
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 7a8dcb82a699..b4def5e083ed 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -95,12 +95,23 @@ static inline struct page *grab_cache_page(struct address_space *mapping, unsign
 
 extern struct page * grab_cache_page_nowait(struct address_space *mapping,
                                 unsigned long index);
+extern struct page * read_cache_page_async(struct address_space *mapping,
+                                unsigned long index, filler_t *filler,
+                                void *data);
 extern struct page * read_cache_page(struct address_space *mapping,
                                 unsigned long index, filler_t *filler,
                                 void *data);
 extern int read_cache_pages(struct address_space *mapping,
                 struct list_head *pages, filler_t *filler, void *data);
 
+static inline struct page *read_mapping_page_async(
+                                                struct address_space *mapping,
+                                             unsigned long index, void *data)
+{
+        filler_t *filler = (filler_t *)mapping->a_ops->readpage;
+        return read_cache_page_async(mapping, index, filler, data);
+}
+
 static inline struct page *read_mapping_page(struct address_space *mapping,
                                              unsigned long index, void *data)
 {
diff --git a/mm/filemap.c b/mm/filemap.c
index 5dfc093ceb3d..070e7547d5b5 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1726,7 +1726,7 @@ int generic_file_readonly_mmap(struct file * file, struct vm_area_struct * vma)
 EXPORT_SYMBOL(generic_file_mmap);
 EXPORT_SYMBOL(generic_file_readonly_mmap);
 
-static inline struct page *__read_cache_page(struct address_space *mapping,
+static struct page *__read_cache_page(struct address_space *mapping,
                                 unsigned long index,
                                 int (*filler)(void *,struct page*),
                                 void *data)
@@ -1763,17 +1763,11 @@ repeat:
         return page;
 }
 
-/**
- * read_cache_page - read into page cache, fill it if needed
- * @mapping:    the page's address_space
- * @index:      the page index
- * @filler:     function to perform the read
- * @data:       destination for read data
- *
- * Read into the page cache. If a page already exists,
- * and PageUptodate() is not set, try to fill the page.
+/*
+ * Same as read_cache_page, but don't wait for page to become unlocked
+ * after submitting it to the filler.
  */
-struct page *read_cache_page(struct address_space *mapping,
+struct page *read_cache_page_async(struct address_space *mapping,
                                 unsigned long index,
                                 int (*filler)(void *,struct page*),
                                 void *data)
@@ -1805,6 +1799,39 @@ retry:
                 page = ERR_PTR(err);
         }
  out:
+        mark_page_accessed(page);
+        return page;
+}
+EXPORT_SYMBOL(read_cache_page_async);
+
+/**
+ * read_cache_page - read into page cache, fill it if needed
+ * @mapping:    the page's address_space
+ * @index:      the page index
+ * @filler:     function to perform the read
+ * @data:       destination for read data
+ *
+ * Read into the page cache. If a page already exists, and PageUptodate() is
+ * not set, try to fill the page then wait for it to become unlocked.
+ *
+ * If the page does not get brought uptodate, return -EIO.
+ */
+struct page *read_cache_page(struct address_space *mapping,
+                                unsigned long index,
+                                int (*filler)(void *,struct page*),
+                                void *data)
+{
+        struct page *page;
+
+        page = read_cache_page_async(mapping, index, filler, data);
+        if (IS_ERR(page))
+                goto out;
+        wait_on_page_locked(page);
+        if (!PageUptodate(page)) {
+                page_cache_release(page);
+                page = ERR_PTR(-EIO);
+        }
+ out:
         return page;
 }
 EXPORT_SYMBOL(read_cache_page);
diff --git a/mm/swapfile.c b/mm/swapfile.c
index a2d9bb4e80df..acc172cbe3aa 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1531,9 +1531,6 @@ asmlinkage long sys_swapon(const char __user * specialfile, int swap_flags)
                 error = PTR_ERR(page);
                 goto bad_swap;
         }
-        wait_on_page_locked(page);
-        if (!PageUptodate(page))
-                goto bad_swap;
         kmap(page);
         swap_header = page_address(page);