Messages in this thread | | | Subject | Re: DEFINE_IDA causing memory leaks? (was Re: [PATCH 1/2] virtio: fix memory leak of virtio ida cache layers) | From | James Bottomley <> | Date | Thu, 17 Sep 2015 10:58:29 -0700 |
| |
On Thu, 2015-09-17 at 13:15 -0400, Tejun Heo wrote: > Hello, > > On Thu, Sep 17, 2015 at 09:48:37AM -0700, James Bottomley wrote: > > Well, there's an easy fix for that. We could have ida_remove() actually > > free the bitmap and not cache it if it's the last layer. That way ida > > would naturally empty and we wouldn't need a destructor. Tejun, would > > that work? > > Yeah, that definitely is one way to go about it. It kinda muddles the > purpose of ida_destroy() tho. I suppose we can rename it to > idr_remove_all() and then do the same to idr. I'm not particularly > objecting to all that but what's wrong with just calling idr_destroy() > on exit paths? If missing the call in modules is an issue, maybe we > can just annotate idr/ida with debugobj?
The argument is that we shouldn't have to explicitly destroy a statically initialized object, so
DEFINE_IDA(someida);
Should just work without having to explicitly do
ida_destory(someida);
somewhere in the exit code. It's about usage patterns. Michael's argument is that if we can't follow the no destructor pattern for DEFINE_IDA() then we shouldn't have it at all, because it's confusing kernel design patterns. The pattern we would have would be
struct ida someida:
ida_init(&someida);
...
ida_destroy(&someida);
so the object explicitly has a constructor matched to a destructor.
James
| |