On Thu, Dec 10, 2015 at 08:10:34AM -0700, Jens Axboe wrote: > On 12/10/2015 07:17 AM, Geliang Tang wrote: > >We already have list_is_last(), it makes sense to also add > >list_is_first() for consistency. This list utility function > >to check for first element in a list. > > Honestly, I think we already have way too many of these kind of helpers. > IMHO they don't really help, they hurt readability. You should know how the > list works anyway, and if you do, then it's a no-brainer what's first and > last. If you don't, then you are bound to screw up in other ways. > > Just my 2 cents. Personally I would disagree. Something like: if (list_is_first(&rq->queuelist, &nd->queue)) is much more readable to me than: if (rq->queuelist.prev == &nd->queue) The first one takes no effort for me -- it's almost English. While the second one takes me a few seconds (and some precious brain cycles) to decipher. Maybe whether it's readable depends on how many years you've been looking at the pattern. But IMHO we shouldn't make "having x # of years staring at kernel code" a prerequisite for being able to read kernel code. -- Josh -- To unsubscribe from this list: send the line "unsubscribe linux-block" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
