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authorTejun Heo <tj@kernel.org>2013-02-27 17:03:35 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2013-02-27 19:10:13 -0800
commit9bb26bc1ffa32ec983860a5a66b6f291a875e39d (patch)
treee821dc2bc21d6a61ae086d4eb45890f9c9c37920 /lib
parent6cdae7416a1c45c2ce105a78187d9b7e8feb9e24 (diff)
downloadlinux-9bb26bc1ffa32ec983860a5a66b6f291a875e39d.tar.gz
idr: make idr_destroy() imply idr_remove_all()
idr is silly in quite a few ways, one of which is how it's supposed to be destroyed - idr_destroy() doesn't release IDs and doesn't even whine if the idr isn't empty. If the caller forgets idr_remove_all(), it simply leaks memory. Even ida gets this wrong and leaks memory on destruction. There is absoltely no reason not to call idr_remove_all() from idr_destroy(). Nobody is abusing idr_destroy() for shrinking free layer buffer and continues to use idr after idr_destroy(), so it's safe to do remove_all from destroy. In the whole kernel, there is only one place where idr_remove_all() is legitimiately used without following idr_destroy() while there are quite a few places where the caller forgets either idr_remove_all() or idr_destroy() leaking memory. This patch makes idr_destroy() call idr_destroy_all() and updates the function description accordingly. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib')
-rw-r--r--lib/idr.c20
1 files changed, 11 insertions, 9 deletions
diff --git a/lib/idr.c b/lib/idr.c
index ca5aa000d6c..b8602e0b30d 100644
--- a/lib/idr.c
+++ b/lib/idr.c
@@ -436,15 +436,6 @@ EXPORT_SYMBOL(idr_remove);
/**
* idr_remove_all - remove all ids from the given idr tree
* @idp: idr handle
- *
- * idr_destroy() only frees up unused, cached idp_layers, but this
- * function will remove all id mappings and leave all idp_layers
- * unused.
- *
- * A typical clean-up sequence for objects stored in an idr tree will
- * use idr_for_each() to free all objects, if necessay, then
- * idr_remove_all() to remove all ids, and idr_destroy() to free
- * up the cached idr_layers.
*/
void idr_remove_all(struct idr *idp)
{
@@ -484,9 +475,20 @@ EXPORT_SYMBOL(idr_remove_all);
/**
* idr_destroy - release all cached layers within an idr tree
* @idp: idr handle
+ *
+ * Free all id mappings and all idp_layers. After this function, @idp is
+ * completely unused and can be freed / recycled. The caller is
+ * responsible for ensuring that no one else accesses @idp during or after
+ * idr_destroy().
+ *
+ * A typical clean-up sequence for objects stored in an idr tree will use
+ * idr_for_each() to free all objects, if necessay, then idr_destroy() to
+ * free up the id mappings and cached idr_layers.
*/
void idr_destroy(struct idr *idp)
{
+ idr_remove_all(idp);
+
while (idp->id_free_cnt) {
struct idr_layer *p = get_from_free_list(idp);
kmem_cache_free(idr_layer_cache, p);