2 files changed, 55 insertions, 49 deletions

diff --git a/fs/ext2/xip.c b/fs/ext2/xip.c
index d44431d1a338..0aa5ac159c09 100644
--- a/fs/ext2/xip.c
+++ b/fs/ext2/xip.c
@@ -15,66 +15,79 @@
 #include "xip.h"
 
 static inline int
-__inode_direct_access(struct inode *inode, sector_t sector, unsigned long *data) {
+__inode_direct_access(struct inode *inode, sector_t sector,
+                      unsigned long *data)
+{
         BUG_ON(!inode->i_sb->s_bdev->bd_disk->fops->direct_access);
         return inode->i_sb->s_bdev->bd_disk->fops
                 ->direct_access(inode->i_sb->s_bdev,sector,data);
 }
 
+static inline int
+__ext2_get_sector(struct inode *inode, sector_t offset, int create,
+                   sector_t *result)
+{
+        struct buffer_head tmp;
+        int rc;
+
+        memset(&tmp, 0, sizeof(struct buffer_head));
+        rc = ext2_get_block(inode, offset/ (PAGE_SIZE/512), &tmp,
+                            create);
+        *result = tmp.b_blocknr;
+
+        /* did we get a sparse block (hole in the file)? */
+        if (!(*result)) {
+                BUG_ON(create);
+                rc = -ENODATA;
+        }
+
+        return rc;
+}
+
 int
-ext2_clear_xip_target(struct inode *inode, int block) {
-        sector_t sector = block*(PAGE_SIZE/512);
+ext2_clear_xip_target(struct inode *inode, int block)
+{
+        sector_t sector = block * (PAGE_SIZE/512);
         unsigned long data;
         int rc;
 
         rc = __inode_direct_access(inode, sector, &data);
-        if (rc)
-                return rc;
-        clear_page((void*)data);
-        return 0;
+        if (!rc)
+                clear_page((void*)data);
+        return rc;
 }
 
 void ext2_xip_verify_sb(struct super_block *sb)
 {
         struct ext2_sb_info *sbi = EXT2_SB(sb);
 
-        if ((sbi->s_mount_opt & EXT2_MOUNT_XIP)) {
-                if ((sb->s_bdev == NULL) ||
-                        sb->s_bdev->bd_disk == NULL ||
-                        sb->s_bdev->bd_disk->fops == NULL ||
-                        sb->s_bdev->bd_disk->fops->direct_access == NULL) {
-                        sbi->s_mount_opt &= (~EXT2_MOUNT_XIP);
-                        ext2_warning(sb, __FUNCTION__,
-                                "ignoring xip option - not supported by bdev");
-                }
+        if ((sbi->s_mount_opt & EXT2_MOUNT_XIP) &&
+            !sb->s_bdev->bd_disk->fops->direct_access) {
+                sbi->s_mount_opt &= (~EXT2_MOUNT_XIP);
+                ext2_warning(sb, __FUNCTION__,
+                             "ignoring xip option - not supported by bdev");
         }
 }
 
-struct page*
-ext2_get_xip_page(struct address_space *mapping, sector_t blockno,
+struct page *
+ext2_get_xip_page(struct address_space *mapping, sector_t offset,
                    int create)
 {
         int rc;
         unsigned long data;
-        struct buffer_head tmp;
+        sector_t sector;
 
-        tmp.b_state = 0;
-        tmp.b_blocknr = 0;
-        rc = ext2_get_block(mapping->host, blockno/(PAGE_SIZE/512) , &tmp,
-                                create);
+        /* first, retrieve the sector number */
+        rc = __ext2_get_sector(mapping->host, offset, create, &sector);
         if (rc)
-                return ERR_PTR(rc);
-        if (tmp.b_blocknr == 0) {
-                /* SPARSE block */
-                BUG_ON(create);
-                return ERR_PTR(-ENODATA);
-        }
+                goto error;
 
+        /* retrieve address of the target data */
         rc = __inode_direct_access
-                (mapping->host,tmp.b_blocknr*(PAGE_SIZE/512) ,&data);
-        if (rc)
-                return ERR_PTR(rc);
+                (mapping->host, sector * (PAGE_SIZE/512), &data);
+        if (!rc)
+                return virt_to_page(data);
 
-        SetPageUptodate(virt_to_page(data));
-        return virt_to_page(data);
+ error:
+        return ERR_PTR(rc);
 }
diff --git a/mm/filemap_xip.c b/mm/filemap_xip.c
index 4553b2c5aab4..8c199f537732 100644
--- a/mm/filemap_xip.c
+++ b/mm/filemap_xip.c
@@ -68,13 +68,12 @@ do_xip_mapping_read(struct address_space *mapping,
                 if (unlikely(IS_ERR(page))) {
                         if (PTR_ERR(page) == -ENODATA) {
                                 /* sparse */
-                                page = virt_to_page(empty_zero_page);
+                                page = ZERO_PAGE(0);
                         } else {
                                 desc->error = PTR_ERR(page);
                                 goto out;
                         }
-                } else
-                        BUG_ON(!PageUptodate(page));
+                }
 
                 /* If users can be writing to this page using arbitrary
                  * virtual addresses, take care about potential aliasing
@@ -84,8 +83,7 @@ do_xip_mapping_read(struct address_space *mapping,
                         flush_dcache_page(page);
 
                 /*
-                 * Ok, we have the page, and it's up-to-date, so
-                 * now we can copy it to user space...
+                 * Ok, we have the page, so now we can copy it to user space...
                  *
                  * The actor routine returns how many bytes were actually used..
                  * NOTE! This may not be the same as how much of a user buffer
@@ -164,7 +162,7 @@ EXPORT_SYMBOL_GPL(xip_file_sendfile);
  * xip_write
  *
  * This function walks all vmas of the address_space and unmaps the
- * empty_zero_page when found at pgoff. Should it go in rmap.c?
+ * ZERO_PAGE when found at pgoff. Should it go in rmap.c?
  */
 static void
 __xip_unmap (struct address_space * mapping,
@@ -187,7 +185,7 @@ __xip_unmap (struct address_space * mapping,
                  * We need the page_table_lock to protect us from page faults,
                  * munmap, fork, etc...
                  */
-                pte = page_check_address(virt_to_page(empty_zero_page), mm,
+                pte = page_check_address(ZERO_PAGE(address), mm,
                                          address);
                 if (!IS_ERR(pte)) {
                         /* Nuke the page table entry. */
@@ -230,7 +228,6 @@ xip_file_nopage(struct vm_area_struct * area,
 
         page = mapping->a_ops->get_xip_page(mapping, pgoff*(PAGE_SIZE/512), 0);
         if (!IS_ERR(page)) {
-                BUG_ON(!PageUptodate(page));
                 return page;
         }
         if (PTR_ERR(page) != -ENODATA)
@@ -245,12 +242,11 @@ xip_file_nopage(struct vm_area_struct * area,
                         pgoff*(PAGE_SIZE/512), 1);
                 if (IS_ERR(page))
                         return NULL;
-                BUG_ON(!PageUptodate(page));
                 /* unmap page at pgoff from all other vmas */
                 __xip_unmap(mapping, pgoff);
         } else {
-                /* not shared and writable, use empty_zero_page */
-                page = virt_to_page(empty_zero_page);
+                /* not shared and writable, use ZERO_PAGE() */
+                page = ZERO_PAGE(address);
         }
 
         return page;
@@ -319,8 +315,6 @@ __xip_file_write(struct file *filp, const char __user *buf,
                         break;
                 }
 
-                BUG_ON(!PageUptodate(page));
-
                 copied = filemap_copy_from_user(page, offset, buf, bytes);
                 flush_dcache_page(page);
                 if (likely(copied > 0)) {
@@ -435,8 +429,7 @@ xip_truncate_page(struct address_space *mapping, loff_t from)
                         return 0;
                 else
                         return PTR_ERR(page);
-        } else
-                BUG_ON(!PageUptodate(page));
+        }
         kaddr = kmap_atomic(page, KM_USER0);
         memset(kaddr + offset, 0, length);
         kunmap_atomic(kaddr, KM_USER0);