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author | Tejun Heo <tj@kernel.org> | 2013-02-28 02:03:35 +0100 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-02-28 04:10:13 +0100 |
commit | 9bb26bc1ffa32ec983860a5a66b6f291a875e39d (patch) | |
tree | e821dc2bc21d6a61ae086d4eb45890f9c9c37920 /lib | |
parent | idr: fix a subtle bug in idr_get_next() (diff) | |
download | linux-9bb26bc1ffa32ec983860a5a66b6f291a875e39d.tar.xz linux-9bb26bc1ffa32ec983860a5a66b6f291a875e39d.zip |
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.c | 20 |
1 files changed, 11 insertions, 9 deletions
diff --git a/lib/idr.c b/lib/idr.c index ca5aa000d6c3..b8602e0b30da 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); |