Messages in this thread | | | From | "Petr Vandrovec" <> | Date | Mon, 3 Mar 2003 19:52:47 +0100 | Subject | Re: [PATCH] make nbd working in 2.5.x |
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On 3 Mar 03 at 19:39, Pavel Machek wrote: > > we use nbd for our diskless systems, and it looks to me like that > > it has some serious problems in 2.5.x... Can you apply this patch > > and forward it to Linus? > > > > There were: > > * Missing disk's queue initialization > > * Driver should use list_del_init: put_request now verifies > > that req->queuelist is empty, and list_del was incompatible > > with this. > > * I converted nbd_end_request back to end_that_request_{first,last} > > as I saw no reason why driver should do it itself... and > > blk_put_request has no place under queue_lock, so apparently when > > semantic changed nobody went through drivers... > > I do not think this is good idea. I am not sure who converted it to > bio, but he surely had good reason to do that.
I think that at the beginning of 2.5.x series there was some thinking about removing end_that_request* completely from the API. As it never happened, and __end_that_request_first()/end_that_request_last() has definitely better quality (like that it does not ignore req->waiting...) than opencoded nbd loop, I prefer using end_that_request* over opencoding bio traversal.
If you want, then just replace blk_put_request() with __blk_put_request(), instead of first change. But I personally will not trust such code, as next time something in bio changes nbd will miss this change again. Petr Vandrovec
> > diff -urdN linux/drivers/block/nbd.c linux/drivers/block/nbd.c > > --- linux/drivers/block/nbd.c 2003-02-28 20:56:05.000000000 +0100 > > +++ linux/drivers/block/nbd.c 2003-03-01 22:53:36.000000000 +0100 > > @@ -76,22 +76,15 @@ > > { > > int uptodate = (req->errors == 0) ? 1 : 0; > > request_queue_t *q = req->q; > > - struct bio *bio; > > - unsigned nsect; > > unsigned long flags; > > > > #ifdef PARANOIA > > requests_out++; > > #endif > > spin_lock_irqsave(q->queue_lock, flags); > > - while((bio = req->bio) != NULL) { > > - nsect = bio_sectors(bio); > > - blk_finished_io(nsect); > > - req->bio = bio->bi_next; > > - bio->bi_next = NULL; > > - bio_endio(bio, nsect << 9, uptodate ? 0 : -EIO); > > + if (!end_that_request_first(req, uptodate, req->nr_sectors)) { > > + end_that_request_last(req); > > } > > - blk_put_request(req); > > spin_unlock_irqrestore(q->queue_lock, flags); > > } > >
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