smb: client: short-circuit in open_cached_dir_by_dentry() if !dentry
When dentry is NULL, the current code acquires the spinlock and traverses
the entire list, but the condition (dentry && cfid->dentry == dentry)
ensures no match will ever be found.
Return -ENOENT early in this case, avoiding unnecessary lock acquisition
and list traversal.
Signed-off-by: Henrique Carvalho <henrique.carvalho@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
diff --git a/fs/smb/client/cached_dir.c b/fs/smb/client/cached_dir.c
index 03bfb91..b36f9f9 100644
--- a/fs/smb/client/cached_dir.c
+++ b/fs/smb/client/cached_dir.c
@@ -416,9 +416,12 @@ int open_cached_dir_by_dentry(struct cifs_tcon *tcon,
if (cfids == NULL)
return -EOPNOTSUPP;
+ if (!dentry)
+ return -ENOENT;
+
spin_lock(&cfids->cfid_list_lock);
list_for_each_entry(cfid, &cfids->entries, entry) {
- if (dentry && cfid->dentry == dentry) {
+ if (cfid->dentry == dentry) {
if (!is_valid_cached_dir(cfid))
break;
cifs_dbg(FYI, "found a cached file handle by dentry\n");
