1. 30 Dec, 2016 4 commits
  2. 29 Dec, 2016 2 commits
    • Olof Johansson's avatar
      mm/filemap: fix parameters to test_bit() · 98473f9f
      Olof Johansson authored
       mm/filemap.c: In function 'clear_bit_unlock_is_negative_byte':
        mm/filemap.c:933:9: error: too few arguments to function 'test_bit'
          return test_bit(PG_waiters);
               ^~~~~~~~
      
      Fixes: b91e1302 ('mm: optimize PageWaiters bit use for unlock_page()')
      Signed-off-by: default avatarOlof Johansson <olof@lixom.net>
      Brown-paper-bag-by: default avatarLinus Torvalds <dummy@duh.com>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      98473f9f
    • Linus Torvalds's avatar
      mm: optimize PageWaiters bit use for unlock_page() · b91e1302
      Linus Torvalds authored
      In commit 62906027 ("mm: add PageWaiters indicating tasks are
      waiting for a page bit") Nick Piggin made our page locking no longer
      unconditionally touch the hashed page waitqueue, which not only helps
      performance in general, but is particularly helpful on NUMA machines
      where the hashed wait queues can bounce around a lot.
      
      However, the "clear lock bit atomically and then test the waiters bit"
      sequence turns out to be much more expensive than it needs to be,
      because you get a nasty stall when trying to access the same word that
      just got updated atomically.
      
      On architectures where locking is done with LL/SC, this would be trivial
      to fix with a new primitive that clears one bit and tests another
      atomically, but that ends up not working on x86, where the only atomic
      operations that return the result end up being cmpxchg and xadd.  The
      atomic bit operations return the old value of the same bit we changed,
      not the value of an unrelated bit.
      
      On x86, we could put the lock bit in the high bit of the byte, and use
      "xadd" with that bit (where the overflow ends up not touching other
      bits), and look at the other bits of the result.  However, an even
      simpler model is to just use a regular atomic "and" to clear the lock
      bit, and then the sign bit in eflags will indicate the resulting state
      of the unrelated bit #7.
      
      So by moving the PageWaiters bit up to bit #7, we can atomically clear
      the lock bit and test the waiters bit on x86 too.  And architectures
      with LL/SC (which is all the usual RISC suspects), the particular bit
      doesn't matter, so they are fine with this approach too.
      
      This avoids the extra access to the same atomic word, and thus avoids
      the costly stall at page unlock time.
      
      The only downside is that the interface ends up being a bit odd and
      specialized: clear a bit in a byte, and test the sign bit.  Nick doesn't
      love the resulting name of the new primitive, but I'd rather make the
      name be descriptive and very clear about the limitation imposed by
      trying to work across all relevant architectures than make it be some
      generic thing that doesn't make the odd semantics explicit.
      
      So this introduces the new architecture primitive
      
          clear_bit_unlock_is_negative_byte();
      
      and adds the trivial implementation for x86.  We have a generic
      non-optimized fallback (that just does a "clear_bit()"+"test_bit(7)"
      combination) which can be overridden by any architecture that can do
      better.  According to Nick, Power has the same hickup x86 has, for
      example, but some other architectures may not even care.
      
      All these optimizations mean that my page locking stress-test (which is
      just executing a lot of small short-lived shell scripts: "make test" in
      the git source tree) no longer makes our page locking look horribly bad.
      Before all these optimizations, just the unlock_page() costs were just
      over 3% of all CPU overhead on "make test".  After this, it's down to
      0.66%, so just a quarter of the cost it used to be.
      
      (The difference on NUMA is bigger, but there this micro-optimization is
      likely less noticeable, since the big issue on NUMA was not the accesses
      to 'struct page', but the waitqueue accesses that were already removed
      by Nick's earlier commit).
      Acked-by: default avatarNick Piggin <npiggin@gmail.com>
      Cc: Dave Hansen <dave.hansen@linux.intel.com>
      Cc: Bob Peterson <rpeterso@redhat.com>
      Cc: Steven Whitehouse <swhiteho@redhat.com>
      Cc: Andrew Lutomirski <luto@kernel.org>
      Cc: Andreas Gruenbacher <agruenba@redhat.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Mel Gorman <mgorman@techsingularity.net>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      b91e1302
  3. 28 Dec, 2016 2 commits
    • Linus Torvalds's avatar
      Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 · 2d706e79
      Linus Torvalds authored
      Pull crypto fix from Herbert Xu:
       "This fixes a hash corruption bug in the marvell driver"
      
      * 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
        crypto: marvell - Copy IVDIG before launching partial DMA ahash requests
      2d706e79
    • Linus Torvalds's avatar
      Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net · 8f18e4d0
      Linus Torvalds authored
      Pull networking fixes from David Miller:
      
       1) Various ipvlan fixes from Eric Dumazet and Mahesh Bandewar.
      
          The most important is to not assume the packet is RX just because
          the destination address matches that of the device. Such an
          assumption causes problems when an interface is put into loopback
          mode.
      
       2) If we retry when creating a new tc entry (because we dropped the
          RTNL mutex in order to load a module, for example) we end up with
          -EAGAIN and then loop trying to replay the request. But we didn't
          reset some state when looping back to the top like this, and if
          another thread meanwhile inserted the same tc entry we were trying
          to, we re-link it creating an enless loop in the tc chain. Fix from
          Daniel Borkmann.
      
       3) There are two different WRITE bits in the MDIO address register for
          the stmmac chip, depending upon the chip variant. Due to a bug we
          could set them both, fix from Hock Leong Kweh.
      
       4) Fix mlx4 bug in XDP_TX handling, from Tariq Toukan.
      
      * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net:
        net: stmmac: fix incorrect bit set in gmac4 mdio addr register
        r8169: add support for RTL8168 series add-on card.
        net: xdp: remove unused bfp_warn_invalid_xdp_buffer()
        openvswitch: upcall: Fix vlan handling.
        ipv4: Namespaceify tcp_tw_reuse knob
        net: korina: Fix NAPI versus resources freeing
        net, sched: fix soft lockup in tc_classify
        net/mlx4_en: Fix user prio field in XDP forward
        tipc: don't send FIN message from connectionless socket
        ipvlan: fix multicast processing
        ipvlan: fix various issues in ipvlan_process_multicast()
      8f18e4d0
  4. 27 Dec, 2016 7 commits
  5. 26 Dec, 2016 5 commits
    • Al Viro's avatar
      arm64: don't pull uaccess.h into *.S · b4b8664d
      Al Viro authored
      Split asm-only parts of arm64 uaccess.h into a new header and use that
      from *.S.
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      b4b8664d
    • Florian Fainelli's avatar
      net: korina: Fix NAPI versus resources freeing · e6afb1ad
      Florian Fainelli authored
      Commit beb0babf ("korina: disable napi on close and restart")
      introduced calls to napi_disable() that were missing before,
      unfortunately this leaves a small window during which NAPI has a chance
      to run, yet we just freed resources since korina_free_ring() has been
      called:
      
      Fix this by disabling NAPI first then freeing resource, and make sure
      that we also cancel the restart task before doing the resource freeing.
      
      Fixes: beb0babf ("korina: disable napi on close and restart")
      Reported-by: default avatarAlexandros C. Couloumbis <alex@ozo.com>
      Signed-off-by: default avatarFlorian Fainelli <f.fainelli@gmail.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      e6afb1ad
    • Daniel Borkmann's avatar
      net, sched: fix soft lockup in tc_classify · 628185cf
      Daniel Borkmann authored
      Shahar reported a soft lockup in tc_classify(), where we run into an
      endless loop when walking the classifier chain due to tp->next == tp
      which is a state we should never run into. The issue only seems to
      trigger under load in the tc control path.
      
      What happens is that in tc_ctl_tfilter(), thread A allocates a new
      tp, initializes it, sets tp_created to 1, and calls into tp->ops->change()
      with it. In that classifier callback we had to unlock/lock the rtnl
      mutex and returned with -EAGAIN. One reason why we need to drop there
      is, for example, that we need to request an action module to be loaded.
      
      This happens via tcf_exts_validate() -> tcf_action_init/_1() meaning
      after we loaded and found the requested action, we need to redo the
      whole request so we don't race against others. While we had to unlock
      rtnl in that time, thread B's request was processed next on that CPU.
      Thread B added a new tp instance successfully to the classifier chain.
      When thread A returned grabbing the rtnl mutex again, propagating -EAGAIN
      and destroying its tp instance which never got linked, we goto replay
      and redo A's request.
      
      This time when walking the classifier chain in tc_ctl_tfilter() for
      checking for existing tp instances we had a priority match and found
      the tp instance that was created and linked by thread B. Now calling
      again into tp->ops->change() with that tp was successful and returned
      without error.
      
      tp_created was never cleared in the second round, thus kernel thinks
      that we need to link it into the classifier chain (once again). tp and
      *back point to the same object due to the match we had earlier on. Thus
      for thread B's already public tp, we reset tp->next to tp itself and
      link it into the chain, which eventually causes the mentioned endless
      loop in tc_classify() once a packet hits the data path.
      
      Fix is to clear tp_created at the beginning of each request, also when
      we replay it. On the paths that can cause -EAGAIN we already destroy
      the original tp instance we had and on replay we really need to start
      from scratch. It seems that this issue was first introduced in commit
      12186be7 ("net_cls: fix unconfigured struct tcf_proto keeps chaining
      and avoid kernel panic when we use cls_cgroup").
      
      Fixes: 12186be7 ("net_cls: fix unconfigured struct tcf_proto keeps chaining and avoid kernel panic when we use cls_cgroup")
      Reported-by: default avatarShahar Klein <shahark@mellanox.com>
      Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
      Cc: Cong Wang <xiyou.wangcong@gmail.com>
      Acked-by: default avatarEric Dumazet <edumazet@google.com>
      Tested-by: default avatarShahar Klein <shahark@mellanox.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      628185cf
    • Linus Torvalds's avatar
      Linux 4.10-rc1 · 7ce7d89f
      Linus Torvalds authored
      7ce7d89f
    • Larry Finger's avatar
      powerpc: Fix build warning on 32-bit PPC · 8ae679c4
      Larry Finger authored
      I am getting the following warning when I build kernel 4.9-git on my
      PowerBook G4 with a 32-bit PPC processor:
      
          AS      arch/powerpc/kernel/misc_32.o
        arch/powerpc/kernel/misc_32.S:299:7: warning: "CONFIG_FSL_BOOKE" is not defined [-Wundef]
      
      This problem is evident after commit 989cea5c ("kbuild: prevent
      lib-ksyms.o rebuilds"); however, this change in kbuild only exposes an
      error that has been in the code since 2005 when this source file was
      created.  That was with commit 9994a338 ("powerpc: Introduce
      entry_{32,64}.S, misc_{32,64}.S, systbl.S").
      
      The offending line does not make a lot of sense.  This error does not
      seem to cause any errors in the executable, thus I am not recommending
      that it be applied to any stable versions.
      
      Thanks to Nicholas Piggin for suggesting this solution.
      
      Fixes: 9994a338 ("powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S")
      Signed-off-by: default avatarLarry Finger <Larry.Finger@lwfinger.net>
      Cc: Nicholas Piggin <npiggin@gmail.com>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Michael Ellerman <mpe@ellerman.id.au>
      Cc: linuxppc-dev@lists.ozlabs.org
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      8ae679c4
  6. 25 Dec, 2016 20 commits