* Steven Rostedt (rostedt@xxxxxxxxxxx) wrote: > 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 Yes. It's worth noting that it is a do_each_thread() / while_each_thread() pair. > and ftrace does this as well. > Look at kernel/trace/ftrace.c at do_for_each_ftrace_rec(). Same here. > > 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). Good point. So would changing hash_for_each_size() to a do_each_hash_size()/while_each_hash_size() make it clearer that this contains a double-loop ? (along with an appropriate comment about break). Thanks, Mathieu > > -- Steve > > -- Mathieu Desnoyers Operating System Efficiency R&D Consultant EfficiOS Inc. http://www.efficios.com -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel