Re: [PATCH 06/10] audit: Factor out chunk replacement code

Chunk replacement code is very similar for the cases where we grow or shrink chunk. Factor the code out into a common helper function. Signed-off-by: Jan Kara <jack(a)suse.cz&gt; --- kernel/audit_tree.c | 86 +++++++++++++++++++++++++---------------------------- 1 file changed, 40 insertions(+), 46 deletions(-)

diff --git a/kernel/audit_tree.c b/kernel/audit_tree.c index 6a01738d1ac2..f419fdfc25b4 100644 --- a/kernel/audit_tree.c +++ b/kernel/audit_tree.c @@ -235,6 +235,38 @@ static struct audit_chunk *find_chunk(struct node *p) return container_of(p, struct audit_chunk, owners[0]); } +static void replace_chunk(struct audit_chunk *new, struct audit_chunk *old, + struct node *skip) +{ + struct audit_tree *owner; + int i, j; + + new->key = old->key; + list_replace_init(&old->trees, &new->trees); + list_for_each_entry(owner, &new->trees, same_root) + owner->root = new; + for (i = j = 0; j < old->count; i++, j++) { + if (&old->owners[j] == skip) { + i--; + continue; + } + owner = old->owners[j].owner; + new->owners[i].owner = owner; + new->owners[i].index = old->owners[j].index - j + i; + if (!owner) /* result of earlier fallback */ + continue; + get_tree(owner); + list_replace_init(&old->owners[j].list, &new->owners[i].list); + } + /* + * Make sure chunk is fully initialized before making it visible in the + * hash. Pairs with a data dependency barrier in READ_ONCE() in + * audit_tree_lookup(). + */ + smp_wmb(); + list_replace_rcu(&old->hash, &new->hash); +} + static void untag_chunk(struct node *p) { struct audit_chunk *chunk = find_chunk(p); @@ -242,7 +274,6 @@ static void untag_chunk(struct node *p) struct audit_chunk *new = NULL; struct audit_tree *owner; int size = chunk->count - 1; - int i, j; fsnotify_get_mark(entry); @@ -291,38 +322,16 @@ static void untag_chunk(struct node *p) chunk->dead = 1; spin_lock(&hash_lock); - new->key = chunk->key; - list_replace_init(&chunk->trees, &new->trees); if (owner->root == chunk) { list_del_init(&owner->same_root); owner->root = NULL; } - - for (i = j = 0; j <= size; i++, j++) { - struct audit_tree *s; - if (&chunk->owners[j] == p) { - list_del_init(&p->list); - i--; - continue; - } - s = chunk->owners[j].owner; - new->owners[i].owner = s; - new->owners[i].index = chunk->owners[j].index - j + i; - if (!s) /* result of earlier fallback */ - continue; - get_tree(s); - list_replace_init(&chunk->owners[j].list, &new->owners[i].list); - } - - list_for_each_entry(owner, &new->trees, same_root) - owner->root = new; + list_del_init(&p->list); /* - * Make sure chunk is fully initialized before making it visible in the - * hash. Pairs with a data dependency barrier in READ_ONCE() in - * audit_tree_lookup(). + * This has to go last when updating chunk as once replace_chunk() is + * called, new RCU readers can see the new chunk. */ - smp_wmb(); - list_replace_rcu(&chunk->hash, &new->hash); + replace_chunk(new, chunk, p); spin_unlock(&hash_lock); fsnotify_detach_mark(entry); mutex_unlock(&entry->group->mark_mutex); @@ -399,7 +408,6 @@ static int create_chunk(struct inode *inode, struct audit_tree *tree) static int tag_chunk(struct inode *inode, struct audit_tree *tree) { struct fsnotify_mark *old_entry, *chunk_entry; - struct audit_tree *owner; struct audit_chunk *chunk, *old; struct node *p; int n; @@ -464,35 +472,21 @@ static int tag_chunk(struct inode *inode, struct audit_tree *tree) fsnotify_put_mark(old_entry); return 0; } - chunk->key = old->key; - list_replace_init(&old->trees, &chunk->trees); - for (n = 0, p = chunk->owners; n < old->count; n++, p++) { - struct audit_tree *s = old->owners[n].owner; - p->owner = s; - p->index = old->owners[n].index; - if (!s) /* result of fallback in untag */ - continue; - get_tree(s); - list_replace_init(&old->owners[n].list, &p->list); - } + p = &chunk->owners[chunk->count - 1]; p->index = (chunk->count - 1) | (1U<<31); p->owner = tree; get_tree(tree); list_add(&p->list, &tree->chunks); - list_for_each_entry(owner, &chunk->trees, same_root) - owner->root = chunk; old->dead = 1; if (!tree->root) { tree->root = chunk; list_add(&tree->same_root, &chunk->trees); } /* - * Make sure chunk is fully initialized before making it visible in the - * hash. Pairs with a data dependency barrier in READ_ONCE() in - * audit_tree_lookup(). + * This has to go last when updating chunk as once replace_chunk() is + * called, new RCU readers can see the new chunk. */ - smp_wmb(); - list_replace_rcu(&old->hash, &chunk->hash); + replace_chunk(chunk, old, NULL); spin_unlock(&hash_lock); fsnotify_detach_mark(old_entry); mutex_unlock(&audit_tree_group->mark_mutex); -- 2.16.4