The patch titled
Subject: idr: make idr_destroy() imply idr_remove_all()
has been added to the -mm tree. Its filename is
idr-make-idr_destroy-imply-idr_remove_all.patch
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From: Tejun Heo <tj@xxxxxxxxxx>
Subject: 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@xxxxxxxxxx>
Cc: "J. Bruce Fields" <bfields@xxxxxxxxxxxx>
Cc: Alasdair Kergon <agk@xxxxxxxxxx>
Cc: Chas Williams <chas@xxxxxxxxxxxxxxxx>
Cc: Christine Caulfield <ccaulfie@xxxxxxxxxx>
Cc: David Airlie <airlied@xxxxxxxx>
Cc: David Teigland <teigland@xxxxxxxxxx>
Cc: Eric Paris <eparis@xxxxxxxxxxxxxx>
Cc: Inki Dae <inki.dae@xxxxxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Cc: John McCutchan <john@xxxxxxxxxxxxxxxxx>
Cc: Joonyoung Shim <jy0922.shim@xxxxxxxxxxx>
Cc: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
Cc: Li Zefan <lizefan@xxxxxxxxxx>
Cc: Ohad Ben-Cohen <ohad@xxxxxxxxxx>
Cc: Robert Love <rlove@xxxxxxxxx>
Cc: Seung-Woo Kim <sw0312.kim@xxxxxxxxxxx>
Cc: Stefan Richter <stefanr@xxxxxxxxxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/idr.c | 20 +++++++++++---------
1 file changed, 11 insertions(+), 9 deletions(-)
diff -puN lib/idr.c~idr-make-idr_destroy-imply-idr_remove_all lib/idr.c
--- a/lib/idr.c~idr-make-idr_destroy-imply-idr_remove_all
+++ a/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);
_
Patches currently in -mm which might be from tj@xxxxxxxxxx are
linux-next.patch
cfq-fix-lock-imbalance-with-failed-allocations.patch
block-restore-proc-partitions-to-not-display-non-partitionable-removable-devices.patch
memcg-do-not-create-memsw-files-if-swap-accounting-is-disabled.patch
memcg-clean-up-swap-accounting-initialization-code.patch
memcg-prevent-changes-to-move_charge_at_immigrate-during-task-attach.patch
memcg-split-part-of-memcg-creation-to-css_online.patch
memcg-fast-hierarchy-aware-child-test.patch
memcg-fast-hierarchy-aware-child-test-fix.patch
memcg-replace-cgroup_lock-with-memcg-specific-memcg_lock.patch
memcg-increment-static-branch-right-after-limit-set.patch
memcg-avoid-dangling-reference-count-in-creation-failure.patch
idr-make-idr_destroy-imply-idr_remove_all.patch
atm-nicstar-dont-use-idr_remove_all.patch
block-loop-dont-use-idr_remove_all.patch
firewire-dont-use-idr_remove_all.patch
drm-dont-use-idr_remove_all.patch
dm-dont-use-idr_remove_all.patch
remoteproc-dont-use-idr_remove_all.patch
rpmsg-dont-use-idr_remove_all.patch
dlm-use-idr_for_each_entry-in-recover_idr_clear-error-path.patch
dlm-dont-use-idr_remove_all.patch
nfs-idr_destroy-no-longer-needs-idr_remove_all.patch
inotify-dont-use-idr_remove_all.patch
cgroup-dont-use-idr_remove_all.patch
idr-deprecate-idr_remove_all.patch
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