[PATCH] inotify/idr leak fix

Fix a bug which was reported and diagnosed by Stefan Jones <[email protected]> IDR trees include a cache of idr_layer objects. There's no way to destroy this cache, so when we discard an overall idr tree we end up leaking some memory. Add and use idr_destroy() for this. v9fs and infiniband also need to use idr_destroy() to avoid leaks. Or, we make the cache global, like radix_tree_preload(). Which is probably better. Later. Cc: Eric Van Hensbergen <[email protected]> Cc: Roland Dreier <[email protected]> Cc: Robert Love <[email protected]> Cc: John McCutchan <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
josf · Oct 23, 2005 · 8d3b359 · 8d3b359
1 parent c0fef67
commit 8d3b359
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diff --git a/fs/inotify.c b/fs/inotify.c
@@ -176,6 +176,7 @@ static inline void put_inotify_dev(struct inotify_device *dev)
 	if (atomic_dec_and_test(&dev->count)) {
 		atomic_dec(&dev->user->inotify_devs);
 		free_uid(dev->user);
+		idr_destroy(&dev->idr);
 		kfree(dev);
 	}
 }

diff --git a/include/linux/idr.h b/include/linux/idr.h
@@ -75,4 +75,5 @@ int idr_pre_get(struct idr *idp, unsigned gfp_mask);
 int idr_get_new(struct idr *idp, void *ptr, int *id);
 int idr_get_new_above(struct idr *idp, void *ptr, int starting_id, int *id);
 void idr_remove(struct idr *idp, int id);
+void idr_destroy(struct idr *idp);
 void idr_init(struct idr *idp);
diff --git a/lib/idr.c b/lib/idr.c
@@ -345,6 +345,19 @@ void idr_remove(struct idr *idp, int id)
 }
 EXPORT_SYMBOL(idr_remove);
 
+/**
+ * idr_destroy - release all cached layers within an idr tree
+ * idp: idr handle
+ */
+void idr_destroy(struct idr *idp)
+{
+	while (idp->id_free_cnt) {
+		struct idr_layer *p = alloc_layer(idp);
+		kmem_cache_free(idr_layer_cache, p);
+	}
+}
+EXPORT_SYMBOL(idr_destroy);
+
 /**
  * idr_find - return pointer for given id
  * @idp: idr handle