[PATCH 09/11] audit: Allocate fsnotify mark independently of chunk
Richard Guy Briggs
rgb at redhat.com
Fri Sep 14 14:09:09 UTC 2018
On 2018-09-04 18:06, Jan Kara wrote:
> Allocate fsnotify mark independently instead of embedding it inside
> chunk. This will allow us to just replace chunk attached to mark when
> growing / shrinking chunk instead of replacing mark attached to inode
> which is a more complex operation.
>
> Signed-off-by: Jan Kara <jack at suse.cz>
> ---
> kernel/audit_tree.c | 64 +++++++++++++++++++++++++++++++++++++++++------------
> 1 file changed, 50 insertions(+), 14 deletions(-)
>
> diff --git a/kernel/audit_tree.c b/kernel/audit_tree.c
> index 0cd08b3581f1..481fdc190c2f 100644
> --- a/kernel/audit_tree.c
> +++ b/kernel/audit_tree.c
> @@ -25,7 +25,7 @@ struct audit_tree {
> struct audit_chunk {
> struct list_head hash;
> unsigned long key;
> - struct fsnotify_mark mark;
> + struct fsnotify_mark *mark;
> struct list_head trees; /* with root here */
> int dead;
> int count;
> @@ -38,6 +38,11 @@ struct audit_chunk {
> } owners[];
> };
>
> +struct audit_tree_mark {
> + struct fsnotify_mark mark;
> + struct audit_chunk *chunk;
> +};
> +
> static LIST_HEAD(tree_list);
> static LIST_HEAD(prune_list);
> static struct task_struct *prune_thread;
> @@ -73,6 +78,7 @@ static struct task_struct *prune_thread;
> */
>
> static struct fsnotify_group *audit_tree_group;
> +static struct kmem_cache *audit_tree_mark_cachep __read_mostly;
>
> static struct audit_tree *alloc_tree(const char *s)
> {
> @@ -142,10 +148,33 @@ static void audit_mark_put_chunk(struct audit_chunk *chunk)
> call_rcu(&chunk->head, __put_chunk);
> }
>
> +static inline struct audit_tree_mark *audit_mark(struct fsnotify_mark *entry)
> +{
> + return container_of(entry, struct audit_tree_mark, mark);
> +}
> +
> +static struct audit_chunk *mark_chunk(struct fsnotify_mark *mark)
> +{
> + return audit_mark(mark)->chunk;
> +}
> +
> static void audit_tree_destroy_watch(struct fsnotify_mark *entry)
> {
> - struct audit_chunk *chunk = container_of(entry, struct audit_chunk, mark);
> + struct audit_chunk *chunk = mark_chunk(entry);
> audit_mark_put_chunk(chunk);
> + kmem_cache_free(audit_tree_mark_cachep, audit_mark(entry));
> +}
> +
> +static struct fsnotify_mark *alloc_mark(void)
> +{
> + struct audit_tree_mark *mark;
Would it make sense to call this local variable "amark" to indicate it
isn't a struct fsnotify_mark, but in fact an audit helper variant?
> +
> + mark = kmem_cache_zalloc(audit_tree_mark_cachep, GFP_KERNEL);
> + if (!mark)
> + return NULL;
> + fsnotify_init_mark(&mark->mark, audit_tree_group);
> + mark->mark.mask = FS_IN_IGNORED;
> + return &mark->mark;
There are no other places where it is used in this patch to name a
variable, but this one I found a bit confusing to follow the
"mark->mark"
> }
>
> static struct audit_chunk *alloc_chunk(int count)
> @@ -159,6 +188,13 @@ static struct audit_chunk *alloc_chunk(int count)
> if (!chunk)
> return NULL;
>
> + chunk->mark = alloc_mark();
> + if (!chunk->mark) {
> + kfree(chunk);
> + return NULL;
> + }
> + audit_mark(chunk->mark)->chunk = chunk;
> +
> INIT_LIST_HEAD(&chunk->hash);
> INIT_LIST_HEAD(&chunk->trees);
> chunk->count = count;
> @@ -167,8 +203,6 @@ static struct audit_chunk *alloc_chunk(int count)
> INIT_LIST_HEAD(&chunk->owners[i].list);
> chunk->owners[i].index = i;
> }
> - fsnotify_init_mark(&chunk->mark, audit_tree_group);
> - chunk->mark.mask = FS_IN_IGNORED;
> return chunk;
> }
>
> @@ -278,7 +312,7 @@ static void replace_chunk(struct audit_chunk *new, struct audit_chunk *old,
> static void untag_chunk(struct node *p)
> {
> struct audit_chunk *chunk = find_chunk(p);
> - struct fsnotify_mark *entry = &chunk->mark;
> + struct fsnotify_mark *entry = chunk->mark;
> struct audit_chunk *new = NULL;
> struct audit_tree *owner;
> int size = chunk->count - 1;
> @@ -298,7 +332,7 @@ static void untag_chunk(struct node *p)
> if (chunk->dead || !(entry->flags & FSNOTIFY_MARK_FLAG_ATTACHED)) {
> mutex_unlock(&entry->group->mark_mutex);
> if (new)
> - fsnotify_put_mark(&new->mark);
> + fsnotify_put_mark(new->mark);
> goto out;
> }
>
> @@ -322,9 +356,9 @@ static void untag_chunk(struct node *p)
> if (!new)
> goto Fallback;
>
> - if (fsnotify_add_mark_locked(&new->mark, entry->connector->obj,
> + if (fsnotify_add_mark_locked(new->mark, entry->connector->obj,
> FSNOTIFY_OBJ_TYPE_INODE, 1)) {
> - fsnotify_put_mark(&new->mark);
> + fsnotify_put_mark(new->mark);
> goto Fallback;
> }
>
> @@ -344,7 +378,7 @@ static void untag_chunk(struct node *p)
> fsnotify_detach_mark(entry);
> mutex_unlock(&entry->group->mark_mutex);
> fsnotify_free_mark(entry);
> - fsnotify_put_mark(&new->mark); /* drop initial reference */
> + fsnotify_put_mark(new->mark); /* drop initial reference */
> goto out;
>
> Fallback:
> @@ -375,7 +409,7 @@ static int create_chunk(struct inode *inode, struct audit_tree *tree)
> return -ENOMEM;
> }
>
> - entry = &chunk->mark;
> + entry = chunk->mark;
> if (fsnotify_add_inode_mark_locked(entry, inode, 0)) {
> mutex_unlock(&audit_tree_group->mark_mutex);
> fsnotify_put_mark(entry);
> @@ -426,7 +460,7 @@ static int tag_chunk(struct inode *inode, struct audit_tree *tree)
> if (!old_entry)
> return create_chunk(inode, tree);
>
> - old = container_of(old_entry, struct audit_chunk, mark);
> + old = mark_chunk(old_entry)->chunk;
>
> /* are we already there? */
> spin_lock(&hash_lock);
> @@ -447,7 +481,7 @@ static int tag_chunk(struct inode *inode, struct audit_tree *tree)
> return -ENOMEM;
> }
>
> - chunk_entry = &chunk->mark;
> + chunk_entry = chunk->mark;
>
> /*
> * mark_mutex protects mark from getting detached and thus also from
> @@ -457,7 +491,7 @@ static int tag_chunk(struct inode *inode, struct audit_tree *tree)
> /* old_entry is being shot, lets just lie */
> mutex_unlock(&audit_tree_group->mark_mutex);
> fsnotify_put_mark(old_entry);
> - fsnotify_put_mark(&chunk->mark);
> + fsnotify_put_mark(chunk->mark);
> return -ENOENT;
> }
>
> @@ -1011,7 +1045,7 @@ static int audit_tree_handle_event(struct fsnotify_group *group,
>
> static void audit_tree_freeing_mark(struct fsnotify_mark *entry, struct fsnotify_group *group)
> {
> - struct audit_chunk *chunk = container_of(entry, struct audit_chunk, mark);
> + struct audit_chunk *chunk = mark_chunk(entry);
>
> evict_chunk(chunk);
>
> @@ -1032,6 +1066,8 @@ static int __init audit_tree_init(void)
> {
> int i;
>
> + audit_tree_mark_cachep = KMEM_CACHE(audit_tree_mark, SLAB_PANIC);
> +
> audit_tree_group = fsnotify_alloc_group(&audit_tree_ops);
> if (IS_ERR(audit_tree_group))
> audit_panic("cannot initialize fsnotify group for rectree watches");
> --
> 2.16.4
>
- RGB
--
Richard Guy Briggs <rgb at redhat.com>
Sr. S/W Engineer, Kernel Security, Base Operating Systems
Remote, Ottawa, Red Hat Canada
IRC: rgb, SunRaycer
Voice: +1.647.777.2635, Internal: (81) 32635
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