On Thu, Mar 30, 2017 at 09:54:52PM +0300, Matan Barak wrote: > > /* Convert a locked reference obtained from rdma_lookup_get_uobject to > > a simple kref by dropping the read/write lock. The caller must pair > > this with uverbs_uobject_put */ > > void rdma_lookup_to_kref(struct ib_uobject *uobj, bool write); > > > > Similarly I think you should add a uobj_remove_commit_kref() wrapper > > which does remove_commit but leaves the caller with a kref, as that > > pattern seems to come up alot in this code as well. > > > > Actually, this isn't that frequent pattern. It mainly happens in > ib_uverbs_lookup_comp_file. There's a different pattern of inc_kref > and then remove_commit which is used in order to copy the latest > events_reported info before releasing the uobject's memory. That is the one I was talking about.. > When this destroy function comes from the user-space, the pd object > is locked, so this test would be atomic and safe. The uobject won't > be destroyed, until the object itself is destroyed. So effectively, > it's like taking another kref :) And this is the sketchyness I don't like - this is something that would be easy to break and you have to rely on quite a few assumptions to know that this is 'safe'. It would be much better to hold the kref - that should be cleaned up before start messing with this much more. Jason -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
