don't put symlink bodies in pagecache into highmem

kmap() in page_follow_link_light() needed to go - allowing to hold
an arbitrary number of kmaps for long is a great way to deadlocking
the system.

new helper (inode_nohighmem(inode)) needs to be used for pagecache
symlinks inodes; done for all in-tree cases.  page_follow_link_light()
instrumented to yell about anything missed.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

2 files changed, 3 insertions, 3 deletions

diff --git a/fs/hpfs/inode.c b/fs/hpfs/inode.c
index 933c73780813..1f3c6d76200b 100644
--- a/fs/hpfs/inode.c
+++ b/fs/hpfs/inode.c
@@ -77,6 +77,7 @@ void hpfs_read_inode(struct inode *i)
                         kfree(ea);
                         i->i_mode = S_IFLNK | 0777;
                         i->i_op = &page_symlink_inode_operations;
+                        inode_nohighmem(i);
                         i->i_data.a_ops = &hpfs_symlink_aops;
                         set_nlink(i, 1);
                         i->i_size = ea_size;
diff --git a/fs/hpfs/namei.c b/fs/hpfs/namei.c
index ae4d5a1fa4c9..506765afa1a3 100644
--- a/fs/hpfs/namei.c
+++ b/fs/hpfs/namei.c
@@ -332,6 +332,7 @@ static int hpfs_symlink(struct inode *dir, struct dentry *dentry, const char *sy
         result->i_blocks = 1;
         set_nlink(result, 1);
         result->i_size = strlen(symlink);
+        inode_nohighmem(result);
         result->i_op = &page_symlink_inode_operations;
         result->i_data.a_ops = &hpfs_symlink_aops;
 
@@ -500,7 +501,7 @@ out:
 
 static int hpfs_symlink_readpage(struct file *file, struct page *page)
 {
-        char *link = kmap(page);
+        char *link = page_address(page);
         struct inode *i = page->mapping->host;
         struct fnode *fnode;
         struct buffer_head *bh;
@@ -516,14 +517,12 @@ static int hpfs_symlink_readpage(struct file *file, struct page *page)
                 goto fail;
         hpfs_unlock(i->i_sb);
         SetPageUptodate(page);
-        kunmap(page);
         unlock_page(page);
         return 0;
 
 fail:
         hpfs_unlock(i->i_sb);
         SetPageError(page);
-        kunmap(page);
         unlock_page(page);
         return err;
 }