Messages in this thread | | | Date | Sun, 13 Dec 2009 14:28:14 -0800 | From | Yinghai Lu <> | Subject | Re: nfs broken in net-next? -- now in mainline -- bisected: d9f5950f90292f7cc42834338dfd5f44dc4cc4ca |
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Eric Dumazet wrote: > Le 13/12/2009 03:41, Yinghai Lu a écrit : >>>> cause the problem: nfs mount fail. >>>> >>>> the setup is: >>>> 64bit kernel, have all needed drivers in kernel, and boot with >>>> ip=dhcp, root disk is 256M ramdisk. >>>> then try to mount nfs.... >>>> >>> change entries default value from 65536 to 256, >>> nfs mount will work. >>> >> interesting: >> >> m:~/dump # grep UDP dmesg.txt >> [ 28.996034] UDP hash table entries: 65536 (order: 11, 10485760 bytes) >> [ 29.032364] UDP-Lite hash table entries: 65536 (order: 11, 10485760 bytes) >> >> will not work >> >> but 32768 will work. > > Thanks a lot for this work Yinghai ! > This last bit helped me a lot ... > > Hmm, udp_lib_get_port() assumes it can loop at least one time in : > > for (last = first + udptable->mask + 1; > first != last; > first++) { > // unit_work > } > > but if udptable->mask == 65535, loop is not entered at all (since last == first) > > We should convert it to a do { } while(...); construct, or use 32bit variables > and (u16) casts. > > Thanks > > [PATCH] udp: udp_lib_get_port() fix > > Now we can have a large udp hash table, udp_lib_get_port() loop > should be converted to a do {} while (cond) form, > or we dont enter it at all if hash table size is exactly 65536. > > Reported-by: Yinghai Lu <yinghai@kernel.org> > Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> > --- > diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c > index 1f95348..f0126fd 100644 > --- a/net/ipv4/udp.c > +++ b/net/ipv4/udp.c > @@ -216,9 +216,8 @@ int udp_lib_get_port(struct sock *sk, unsigned short snum, > * force rand to be an odd multiple of UDP_HTABLE_SIZE > */ > rand = (rand | 1) * (udptable->mask + 1); > - for (last = first + udptable->mask + 1; > - first != last; > - first++) { > + last = first + udptable->mask + 1; > + do { > hslot = udp_hashslot(udptable, net, first); > bitmap_zero(bitmap, PORTS_PER_CHAIN); > spin_lock_bh(&hslot->lock); > @@ -238,7 +237,7 @@ int udp_lib_get_port(struct sock *sk, unsigned short snum, > snum += rand; > } while (snum != first); > spin_unlock_bh(&hslot->lock); > - } > + } while (++first != last); > goto fail; > } else { > hslot = udp_hashslot(udptable, net, snum);
thanks. that fix the problem.
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