From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx147.postini.com [74.125.245.147]) by kanga.kvack.org (Postfix) with SMTP id C6F3C6B005D for ; Tue, 4 Sep 2012 11:35:51 -0400 (EDT) Message-ID: <1346772948.27919.9.camel@gandalf.local.home> Subject: Re: [PATCH v3 01/17] hashtable: introduce a small and naive hashtable From: Steven Rostedt Date: Tue, 04 Sep 2012 11:35:48 -0400 In-Reply-To: <20120828230050.GA3337@Krystal> References: <20120824203332.GF21325@google.com> <5037E9D9.9000605@gmail.com> <20120824212348.GK21325@google.com> <5038074D.300@gmail.com> <20120824230740.GN21325@google.com> <20120825042419.GA27240@Krystal> <503C95E4.3010000@gmail.com> <20120828101148.GA21683@Krystal> <503CAB1E.5010408@gmail.com> <20120828115638.GC23818@Krystal> <20120828230050.GA3337@Krystal> Content-Type: text/plain; charset="ISO-8859-15" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Mathieu Desnoyers Cc: Sasha Levin , Tejun Heo , torvalds@linux-foundation.org, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, paul.gortmaker@windriver.com, davem@davemloft.net, mingo@elte.hu, ebiederm@xmission.com, aarcange@redhat.com, ericvh@gmail.com, netdev@vger.kernel.org, josh@joshtriplett.org, eric.dumazet@gmail.com, axboe@kernel.dk, agk@redhat.com, dm-devel@redhat.com, neilb@suse.de, ccaulfie@redhat.com, teigland@redhat.com, Trond.Myklebust@netapp.com, bfields@fieldses.org, fweisbec@gmail.com, jesse@nicira.com, venkat.x.venkatsubra@oracle.com, ejt@redhat.com, snitzer@redhat.com, edumazet@google.com, linux-nfs@vger.kernel.org, dev@openvswitch.org, rds-devel@oss.oracle.com, lw@cn.fujitsu.com On Tue, 2012-08-28 at 19:00 -0400, Mathieu Desnoyers wrote: > Looking again at: > > +#define hash_for_each_size(name, bits, bkt, node, obj, member) \ > + for (bkt = 0; bkt < HASH_SIZE(bits); bkt++) \ > + hlist_for_each_entry(obj, node, &name[bkt], member) > > you will notice that a "break" or "continue" in the inner loop will not > affect the outer loop, which is certainly not what the programmer would > expect! > > I advise strongly against creating such error-prone construct. > A few existing loop macros do this. But they require a do { } while () approach, and all have a comment. It's used by do_each_thread() in sched.h and ftrace does this as well. Look at kernel/trace/ftrace.c at do_for_each_ftrace_rec(). Yes it breaks 'break' but it does not break 'continue' as it would just go to the next item that would have been found (like a normal for would). -- Steve -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org