[PATCH 4/7] audit: optimize add to parent skipping needless search and consuming parent ref

[Richard Guy Briggs]

When parent has just been created there is no need to search for the parent in
the list.  Add a parameter to skip the search and consume the parent reference
no matter what happens.

Signed-off-by: Richard Guy Briggs <r...@redhat.com>
---
 kernel/audit_watch.c |   23 +++++++++++++++--------
 1 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/kernel/audit_watch.c b/kernel/audit_watch.c
index ad9c168..f209448 100644
--- a/kernel/audit_watch.c
+++ b/kernel/audit_watch.c
@@ -372,15 +372,20 @@ static int audit_get_nd(struct audit_watch *watch, struct 
path *parent)
 }
 
 /* Associate the given rule with an existing parent.
- * Caller must hold audit_filter_mutex. */
+ * Caller must hold audit_filter_mutex.
+ * Consumes parent reference. */
 static void audit_add_to_parent(struct audit_krule *krule,
-                               struct audit_parent *parent)
+                               struct audit_parent *parent,
+                               int new)
 {
        struct audit_watch *w, *watch = krule->watch;
        int watch_found = 0;
 
        BUG_ON(!mutex_is_locked(&audit_filter_mutex));
 
+       if (new)
+               goto not_found;
+
        list_for_each_entry(w, &parent->watches, wlist) {
                if (strcmp(watch->path, w->path))
                        continue;
@@ -396,12 +401,15 @@ static void audit_add_to_parent(struct audit_krule *krule,
                break;
        }
 
+not_found:
        if (!watch_found) {
-               audit_get_parent(parent);
                watch->parent = parent;
 
                list_add(&watch->wlist, &parent->watches);
-       }
+       } else
+               /* match get in audit_find_parent or audit_init_parent */
+               audit_put_parent(parent);
+
        list_add(&krule->rlist, &watch->rules);
 }
 
@@ -413,6 +421,7 @@ int audit_add_watch(struct audit_krule *krule, struct 
list_head **list)
        struct audit_parent *parent;
        struct path parent_path;
        int h, ret = 0;
+       int new = 0;
 
        mutex_unlock(&audit_filter_mutex);
 
@@ -433,12 +442,10 @@ int audit_add_watch(struct audit_krule *krule, struct 
list_head **list)
                        ret = PTR_ERR(parent);
                        goto error;
                }
+               new = 1;
        }
 
-       audit_add_to_parent(krule, parent);
-
-       /* match get in audit_find_parent or audit_init_parent */
-       audit_put_parent(parent);
+       audit_add_to_parent(krule, parent, new);
 
        h = audit_hash_ino((u32)watch->ino);
        *list = &audit_inode_hash[h];
-- 
1.7.1

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