ok, does anyone mind if I commit it as-is?
-a On 21 December 2016 at 13:37, Vincenzo Maffione <v.maffi...@gmail.com> wrote: > Hi Luigi, > I attached a minimal change containing two fixes: > > - change IFNET_WLOCK into IFNET_RLOCK, to fix the cxgbe issue related > to this thread > - use the proper locking functions for the "worker_lock", unrelated > but needed to avoid the O.S. to trap because of a mismatch between > MTX_SPIN and MTX_DEF. > > Cheers, > Vincenzo > > 2016-12-21 20:30 GMT+01:00 Luigi Rizzo <ri...@iet.unipi.it>: >> On Wed, Dec 21, 2016 at 11:15 AM, Vincenzo Maffione >> <v.maffi...@gmail.com> wrote: >>> Hi, >>> There is no commit related to that in the FreeBSD svn or git. >>> >>> The fix has been published to the github netmap repository here >>> (branch master): https://github.com/luigirizzo/netmap >>> >>> What we should do is to import all the recent updates from the github >>> into HEAD. I can prepare a patch for HEAD, if you wish. Just let me >>> know. >> >> I just checked and the diff between FreeBSD head and netmap head >> in github is almost 3k lines due to a lot of recent refactoring. >> So, if there is an easy way to extract just the locking change that would >> be preferable as an interim solution. >> >> cheers >> luigi >> >>> >>> Cheers, >>> Vincenzo >>> >>> >>> 2016-12-20 21:45 GMT+01:00 Adrian Chadd <adrian.ch...@gmail.com>: >>>> hi, >>>> >>>> What's the commit? We should get it into -HEAD asap. >>>> >>>> >>>> -adrian >>>> >>>> >>>> On 20 December 2016 at 01:25, Vincenzo Maffione <v.maffi...@gmail.com> >>>> wrote: >>>>> Ok, applied to the netmap github repo. >>>>> This fix will be published when Luigi does the next commit on FreeBSD. >>>>> >>>>> Cheers, >>>>> Vincenzo >>>>> >>>>> 2016-12-19 20:05 GMT+01:00 Navdeep Parhar <n...@freebsd.org>: >>>>>> IFNET_RLOCK will work, thanks. >>>>>> >>>>>> Navdeep >>>>>> >>>>>> On Mon, Dec 19, 2016 at 3:21 AM, Vincenzo Maffione >>>>>> <v.maffi...@gmail.com> wrote: >>>>>>> Hi Navdeep, >>>>>>> >>>>>>> Indeed, we have reviewed the code, and we think it is ok to >>>>>>> implement nm_os_ifnet_lock() with IFNET_RLOCK(), instead of using >>>>>>> IFNET_WLOCK(). >>>>>>> Since IFNET_RLOCK() results into sx_slock(), this should fix the issue. >>>>>>> >>>>>>> On FreeBSD, this locking is needed to protect a flag read by >>>>>>> nm_iszombie(). >>>>>>> However, on Linux the same lock is also needed to protect the call to >>>>>>> the nm_hw_register() callback, so we prefer to have an "unified" >>>>>>> locking scheme, i.e. always calling nm_hw_register under the lock. >>>>>>> >>>>>>> Does this make sense to you? Would it be easy for you to make a quick >>>>>>> test by replacing IFNET_WLOCK with IFNET_RLOCK? >>>>>>> >>>>>>> Thanks, >>>>>>> Vincenzo >>>>>>> >>>>>>> 2016-12-17 23:28 GMT+01:00 Navdeep Parhar <n...@freebsd.org>: >>>>>>>> Luigi, Vincenzo, >>>>>>>> >>>>>>>> The last major update to netmap (r307394 and followups) broke cxgbe's >>>>>>>> native netmap support. The problem is that netmap_hw_reg now holds an >>>>>>>> rw_lock around the driver's netmap_on/off routines. It has always been >>>>>>>> safe for the driver to sleep during these operations but now it panics >>>>>>>> instead. >>>>>>>> >>>>>>>> Why is IFNET_WLOCK needed here? It seems like a regression to disallow >>>>>>>> sleep on the control path. >>>>>>>> >>>>>>>> Regards, >>>>>>>> Navdeep >>>>>>>> >>>>>>>> begin_synchronized_op with the following non-sleepable locks held: >>>>>>>> exclusive rw ifnet_rw (ifnet_rw) r = 0 (0xffffffff8271d680) locked @ >>>>>>>> /root/ws/head/sys/dev/netmap/netmap_freebsd.c:95 >>>>>>>> stack backtrace: >>>>>>>> #0 0xffffffff810837a5 at witness_debugger+0xe5 >>>>>>>> #1 0xffffffff81084d88 at witness_warn+0x3b8 >>>>>>>> #2 0xffffffff83ef2bcc at begin_synchronized_op+0x6c >>>>>>>> #3 0xffffffff83f14beb at cxgbe_netmap_reg+0x5b >>>>>>>> #4 0xffffffff809846f1 at netmap_hw_reg+0x81 >>>>>>>> #5 0xffffffff809806de at netmap_do_regif+0x19e >>>>>>>> #6 0xffffffff8098121d at netmap_ioctl+0x7ad >>>>>>>> #7 0xffffffff8098682f at freebsd_netmap_ioctl+0x5f >>>>>>> >>>>>>> >>>>>>> >>>>>>> -- >>>>>>> Vincenzo Maffione >>>>>>> _______________________________________________ >>>>>>> freebsd-net@freebsd.org mailing list >>>>>>> https://lists.freebsd.org/mailman/listinfo/freebsd-net >>>>>>> To unsubscribe, send any mail to "freebsd-net-unsubscr...@freebsd.org" >>>>> >>>>> >>>>> >>>>> -- >>>>> Vincenzo Maffione >>>>> _______________________________________________ >>>>> freebsd-net@freebsd.org mailing list >>>>> https://lists.freebsd.org/mailman/listinfo/freebsd-net >>>>> To unsubscribe, send any mail to "freebsd-net-unsubscr...@freebsd.org" >>> >>> >>> >>> -- >>> Vincenzo Maffione >> >> >> >> -- >> -----------------------------------------+------------------------------- >> Prof. Luigi RIZZO, ri...@iet.unipi.it . Dip. di Ing. dell'Informazione >> http://www.iet.unipi.it/~luigi/ . Universita` di Pisa >> TEL +39-050-2217533 . via Diotisalvi 2 >> Mobile +39-338-6809875 . 56122 PISA (Italy) >> -----------------------------------------+------------------------------- > > > > -- > Vincenzo Maffione _______________________________________________ freebsd-net@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "freebsd-net-unsubscr...@freebsd.org"
