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-rw-r--r--fs/romfs/mmap-nommu.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/fs/romfs/mmap-nommu.c b/fs/romfs/mmap-nommu.c
index f0511e816967..eed99428f104 100644
--- a/fs/romfs/mmap-nommu.c
+++ b/fs/romfs/mmap-nommu.c
@@ -27,14 +27,18 @@ static unsigned long romfs_get_unmapped_area(struct file *file,
{
struct inode *inode = file->f_mapping->host;
struct mtd_info *mtd = inode->i_sb->s_mtd;
- unsigned long isize, offset;
+ unsigned long isize, offset, maxpages, lpages;
if (!mtd)
goto cant_map_directly;
+ /* the mapping mustn't extend beyond the EOF */
+ lpages = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
isize = i_size_read(inode);
offset = pgoff << PAGE_SHIFT;
- if (offset > isize || len > isize || offset > isize - len)
+
+ maxpages = (isize + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ if ((pgoff >= maxpages) || (maxpages - pgoff < lpages))
return (unsigned long) -EINVAL;
/* we need to call down to the MTD layer to do the actual mapping */