Hi Jan, I'm currently working on some cleanups on IPI code too and working on top of these patches, just have a few comments:
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. > > 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. Thanks. > > - 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 > -- 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/
