On Fri, Apr 14, 2017 at 2:08 AM, Wolfgang Bumiller <w.bumil...@proxmox.com> wrote: > Before I do that - trying to wrap my head around the interdependencies > here better to be thorough - I noticed that tcf_hash_release() can > return ACT_P_DELETED. The ACT_P_CREATED case means tcf_hash_create() > was used, in the other case the tc_action's ref & bind count is bumped > by tcf_hash_check() and then also decremented by tcf_hash_release() if > it existed, iow. kept at 1, but not always: It does always happen in > act_police.c but in other files such as act_bpf.c or act_connmark.c if > eg. bind is set they return without decrementing, so both ref&bind count > are bumped when they return - the refcount logic isn't easy to follow > for a newcomer. Now there are two uses of __tcf_hash_release() in > act_api.c which check for a return value of ACT_P_DELETED, in which case > they call module_put().
That's the nasty part... IIRC, Jamal has fixed two bugs on action refcnt'ing. We really need to clean up the code. > So I'm not sure exactly how the module and tc_action counts are related > (and I usually like to understand my own patches ;-) ). Each action holds a refcnt to its module, each filter holds a refcnt to its bound or referenced (unbound) action. > Maybe I'm missing something obvious but I'm currently a bit confused as > to whether the tcf_hash_release() call there is okay, or should have its > return value checked or should depend on ->init()'s ACT_P_CREATED value > as well? > I think it's the same? If we have ACT_P_CREATED here, tcf_hash_release() will return ACT_P_DELETED for sure because the newly created action has refcnt==1? Thanks.
