Don't pass inode to ->d_hash() and ->d_compare()

Instances either don't look at it at all (the majority of cases) or
only want it to find the superblock (which can be had as dentry->d_sb).
A few cases that want more are actually safe with dentry->d_inode -
the only precaution needed is the check that it hadn't been replaced with
NULL by rmdir() or by overwriting rename(), which case should be simply
treated as cache miss.

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

1 files changed, 4 insertions, 3 deletions

diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index f3a570e7c257..71290463a1d3 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -796,15 +796,16 @@ static int sysctl_is_seen(struct ctl_table_header *p)
         return res;
 }
 
-static int proc_sys_compare(const struct dentry *parent,
-                const struct inode *pinode,
-                const struct dentry *dentry, const struct inode *inode,
+static int proc_sys_compare(const struct dentry *parent, const struct dentry *dentry,
                 unsigned int len, const char *str, const struct qstr *name)
 {
         struct ctl_table_header *head;
+        struct inode *inode;
+
         /* Although proc doesn't have negative dentries, rcu-walk means
          * that inode here can be NULL */
         /* AV: can it, indeed? */
+        inode = ACCESS_ONCE(dentry->d_inode);
         if (!inode)
                 return 1;
         if (name->len != len)