Hi, On Thu 30-01-14 13:39:18, Frederic Weisbecker wrote: > I'm currently working on some cleanups on IPI code too and working on top > of these patches, just have a few comments: Great, thanks!
> On Mon, Dec 23, 2013 at 09:39:23PM +0100, Jan Kara wrote: > > Abusing rq->csd.list for a list of requests to complete is rather ugly. > > Especially since using queuelist should be safe and much cleaner. > > It would be nice to have a few more details that explain why doing so is safe > wrt a block request lifecycle. At least something that tells why rq->queuelist > can't be ever used concurrently by the time we send the IPI and we > trigger/raise > the softirq. Sure. Should I send the patch to you with an updated changelog and added comment you requested? > > Signed-off-by: Jan Kara <[email protected]> > > --- > > block/blk-softirq.c | 12 ++++++------ > > 1 file changed, 6 insertions(+), 6 deletions(-) > > > > diff --git a/block/blk-softirq.c b/block/blk-softirq.c > > index 57790c1a97eb..7ea5534096d5 100644 > > --- a/block/blk-softirq.c > > +++ b/block/blk-softirq.c > > @@ -30,8 +30,8 @@ static void blk_done_softirq(struct softirq_action *h) > > while (!list_empty(&local_list)) { > > struct request *rq; > > > > - rq = list_entry(local_list.next, struct request, csd.list); > > - list_del_init(&rq->csd.list); > > + rq = list_entry(local_list.next, struct request, queuelist); > > + list_del_init(&rq->queuelist); > > rq->q->softirq_done_fn(rq); > > } > > } > > @@ -45,9 +45,9 @@ static void trigger_softirq(void *data) > > > > local_irq_save(flags); > > list = this_cpu_ptr(&blk_cpu_done); > > - list_add_tail(&rq->csd.list, list); > > + list_add_tail(&rq->queuelist, list); > > And given that's an alternate use of rq->queuelist, perhaps add a comment > to unconfuse people. Good idea, will do. Honza > > > > - if (list->next == &rq->csd.list) > > + if (list->next == &rq->queuelist) > > raise_softirq_irqoff(BLOCK_SOFTIRQ); > > > > local_irq_restore(flags); > > @@ -136,7 +136,7 @@ void __blk_complete_request(struct request *req) > > struct list_head *list; > > do_local: > > list = this_cpu_ptr(&blk_cpu_done); > > - list_add_tail(&req->csd.list, list); > > + list_add_tail(&req->queuelist, list); > > > > /* > > * if the list only contains our just added request, > > @@ -144,7 +144,7 @@ do_local: > > * entries there, someone already raised the irq but it > > * hasn't run yet. > > */ > > - if (list->next == &req->csd.list) > > + if (list->next == &req->queuelist) > > raise_softirq_irqoff(BLOCK_SOFTIRQ); > > } else if (raise_blk_irq(ccpu, req)) > > goto do_local; > > -- > > 1.8.1.4 > > -- Jan Kara <[email protected]> SUSE Labs, CR -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
