Messages in this thread | | | Date | Wed, 28 Nov 2012 17:12:03 -0800 | From | Kent Overstreet <> | Subject | Re: [PATCH 12/25] aio: Refcounting cleanup |
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On Wed, Nov 28, 2012 at 04:17:59PM -0800, Zach Brown wrote: > > > struct kioctx { > > atomic_t users; > > - int dead; > > + atomic_t dead; > > Do we want to be paranoid and atomic_set() that to 0 when the ioctx is > allocated?
I suppose we should, yeah.
> > + while (!list_empty(&ctx->active_reqs)) { > > + struct list_head *pos = ctx->active_reqs.next; > > + struct kiocb *iocb = list_kiocb(pos); > > I'd use list_first_entry() and ignore the list_kiocb() wrapper, I think.
Fine by me.
> > > + if (!atomic_xchg(&ctx->dead, 1)) { > > + hlist_del_rcu(&ctx->list); > > + synchronize_rcu(); > > > + hlist_for_each_entry_rcu(ctx, n, &mm->ioctx_list, list) > > + if (ctx->user_id == ctx_id){ > > + BUG_ON(atomic_read(&ctx->dead)); > > Hmm. Won't it be possible to race lookup and io_destroy() to hit this > BUG?
Ouch, yes. Dunno what I was thinking when I added that.
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