Jens Axboe wrote: > On Mon, Dec 08 2008, Alan D. Brunelle wrote: >> Mike Anderson wrote: >>> Jens Axboe <jens.axboe@xxxxxxxxxx> wrote: >>>> On Fri, Dec 05 2008, Alan D. Brunelle wrote: >>>>> Commands needing to be retried (TUR in this case) would result in a block >>>>> I/O request being re-used, without being re-initialized properly. This >>>>> patch ensures that the requests are correctly re-initialized via >>>>> standard allocation means. >>>>> >>>>> Prior to this patch, boots were failing consistently as in: >>>>> http://lkml.org/lkml/2008/12/5/161 >>>>> >>>>> With this patch in place, the system is booting reliably. >>>>> >>>>> Signed-off-by: Alan D. Brunelle <alan.brunelle@xxxxxx> >>>>> Cc: Jens Axboe <jens.axboe@xxxxxxxxxx> >>>> Looks good. >>>> >>>> Acked-by: Jens Axboe <jens.axboe@xxxxxxxxxx> >>>> >>>> Perhaps James can push it in, I'm about to shutdown for the day... >>>> >>> I know a failure was not detected in the hp_sw_start_stop function, but it >>> uses the same retry method as hp_sw_tur we should update this function >>> also. >>> >>> I made a quick scope of callers of blk_get_request and I did not see a >>> repeated of this retry usage model. I will make another pass to see if I >>> missed something. >> drivers/cdrom/cdrom.c:cdrom_read_cdda_bpc() is even worse: it gets one >> request, then sits in a while loop re-using the same request over and >> over again. > > Sigh, it does indeed look messy... > >> Since blk_rq_init() is an exported symbol, perhaps instead of having the >> three callers realloc, it _may_ be sufficient to just have them call >> that before re-use? (See attached un-tested patch for an example.) > > I think that's a really bad idea, since it basically just clears the > 'rq'. If you have that rq on some list (timeout, for instance), the > kernel will not be happy. I think we have to, for now at least, put and > get a request before looping. Then for 2.6.29 we can hopefully improve > this situation! OK, I'll work that one up for 2.6.28 and test it out this morning. Alan -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
