Doug / smarc-fsl-linux-kernel

26 Apr, 2012

1 commit

21 Apr, 2012

2 commits

  • ec8f23ce0   net: Convert all sysctl registrations to register_net_sysctl ... Browse Code »

    This results in code with less boiler plate that is a bit easier
    to read.

    Additionally stops us from using compatibility code in the sysctl
    core, hastening the day when the compatibility code can be removed.

    Signed-off-by: Eric W. Biederman
    Acked-by: Pavel Emelyanov
    Signed-off-by: David S. Miller

    Eric W. Biederman
     
  • 5dd3df105   net: Move all of the network sysctls without a namespace into init_net. ... Browse Code »

    This makes it clearer which sysctls are relative to your current network
    namespace.

    This makes it a little less error prone by not exposing sysctls for the
    initial network namespace in other namespaces.

    This is the same way we handle all of our other network interfaces to
    userspace and I can't honestly remember why we didn't do this for
    sysctls right from the start.

    Signed-off-by: Eric W. Biederman
    Acked-by: Pavel Emelyanov
    Signed-off-by: David S. Miller

    Eric W. Biederman
     

16 Apr, 2012

1 commit

04 Apr, 2012

1 commit

  • eb6a24816   af_unix: reduce high order page allocations ... Browse Code »

    unix_dgram_sendmsg() currently builds linear skbs, and this can stress
    page allocator with high order page allocations. When memory gets
    fragmented, this can eventually fail.

    We can try to use order-2 allocations for skb head (SKB_MAX_ALLOC) plus
    up to 16 page fragments to lower pressure on buddy allocator.

    This patch has no effect on messages of less than 16064 bytes.
    (on 64bit arches with PAGE_SIZE=4096)

    For bigger messages (from 16065 to 81600 bytes), this patch brings
    reliability at the expense of performance penalty because of extra pages
    allocations.

    netperf -t DG_STREAM -T 0,2 -- -m 16064 -s 200000
    ->4086040 Messages / 10s

    netperf -t DG_STREAM -T 0,2 -- -m 16068 -s 200000
    ->3901747 Messages / 10s

    Signed-off-by: Eric Dumazet
    Signed-off-by: David S. Miller

    Eric Dumazet
     

24 Mar, 2012

1 commit

  • 626cf2366   poll: add poll_requested_events() and poll_does_not_wait() functions ... Browse Code »

    In some cases the poll() implementation in a driver has to do different
    things depending on the events the caller wants to poll for. An example
    is when a driver needs to start a DMA engine if the caller polls for
    POLLIN, but doesn't want to do that if POLLIN is not requested but instead
    only POLLOUT or POLLPRI is requested. This is something that can happen
    in the video4linux subsystem among others.

    Unfortunately, the current epoll/poll/select implementation doesn't
    provide that information reliably. The poll_table_struct does have it: it
    has a key field with the event mask. But once a poll() call matches one
    or more bits of that mask any following poll() calls are passed a NULL
    poll_table pointer.

    Also, the eventpoll implementation always left the key field at ~0 instead
    of using the requested events mask.

    This was changed in eventpoll.c so the key field now contains the actual
    events that should be polled for as set by the caller.

    The solution to the NULL poll_table pointer is to set the qproc field to
    NULL in poll_table once poll() matches the events, not the poll_table
    pointer itself. That way drivers can obtain the mask through a new
    poll_requested_events inline.

    The poll_table_struct can still be NULL since some kernel code calls it
    internally (netfs_state_poll() in ./drivers/staging/pohmelfs/netfs.h). In
    that case poll_requested_events() returns ~0 (i.e. all events).

    Very rarely drivers might want to know whether poll_wait will actually
    wait. If another earlier file descriptor in the set already matched the
    events the caller wanted to wait for, then the kernel will return from the
    select() call without waiting. This might be useful information in order
    to avoid doing expensive work.

    A new helper function poll_does_not_wait() is added that drivers can use
    to detect this situation. This is now used in sock_poll_wait() in
    include/net/sock.h. This was the only place in the kernel that needed
    this information.

    Drivers should no longer access any of the poll_table internals, but use
    the poll_requested_events() and poll_does_not_wait() access functions
    instead. In order to enforce that the poll_table fields are now prepended
    with an underscore and a comment was added warning against using them
    directly.

    This required a change in unix_dgram_poll() in unix/af_unix.c which used
    the key field to get the requested events. It's been replaced by a call
    to poll_requested_events().

    For qproc it was especially important to change its name since the
    behavior of that field changes with this patch since this function pointer
    can now be NULL when that wasn't possible in the past.

    Any driver accessing the qproc or key fields directly will now fail to compile.

    Some notes regarding the correctness of this patch: the driver's poll()
    function is called with a 'struct poll_table_struct *wait' argument. This
    pointer may or may not be NULL, drivers can never rely on it being one or
    the other as that depends on whether or not an earlier file descriptor in
    the select()'s fdset matched the requested events.

    There are only three things a driver can do with the wait argument:

    1) obtain the key field:

    events = wait ? wait->key : ~0;

    This will still work although it should be replaced with the new
    poll_requested_events() function (which does exactly the same).
    This will now even work better, since wait is no longer set to NULL
    unnecessarily.

    2) use the qproc callback. This could be deadly since qproc can now be
    NULL. Renaming qproc should prevent this from happening. There are no
    kernel drivers that actually access this callback directly, BTW.

    3) test whether wait == NULL to determine whether poll would return without
    waiting. This is no longer sufficient as the correct test is now
    wait == NULL || wait->_qproc == NULL.

    However, the worst that can happen here is a slight performance hit in
    the case where wait != NULL and wait->_qproc == NULL. In that case the
    driver will assume that poll_wait() will actually add the fd to the set
    of waiting file descriptors. Of course, poll_wait() will not do that
    since it tests for wait->_qproc. This will not break anything, though.

    There is only one place in the whole kernel where this happens
    (sock_poll_wait() in include/net/sock.h) and that code will be replaced
    by a call to poll_does_not_wait() in the next patch.

    Note that even if wait->_qproc != NULL drivers cannot rely on poll_wait()
    actually waiting. The next file descriptor from the set might match the
    event mask and thus any possible waits will never happen.

    Signed-off-by: Hans Verkuil
    Reviewed-by: Jonathan Corbet
    Reviewed-by: Al Viro
    Cc: Davide Libenzi
    Signed-off-by: Hans de Goede
    Cc: Mauro Carvalho Chehab
    Cc: David Miller
    Cc: Eric Dumazet
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Hans Verkuil
     

22 Mar, 2012

1 commit

  • e2a0883e4   Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs ... Browse Code »

    Pull vfs pile 1 from Al Viro:
    "This is _not_ all; in particular, Miklos' and Jan's stuff is not there
    yet."

    * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (64 commits)
    ext4: initialization of ext4_li_mtx needs to be done earlier
    debugfs-related mode_t whack-a-mole
    hfsplus: add an ioctl to bless files
    hfsplus: change finder_info to u32
    hfsplus: initialise userflags
    qnx4: new helper - try_extent()
    qnx4: get rid of qnx4_bread/qnx4_getblk
    take removal of PF_FORKNOEXEC to flush_old_exec()
    trim includes in inode.c
    um: uml_dup_mmap() relies on ->mmap_sem being held, but activate_mm() doesn't hold it
    um: embed ->stub_pages[] into mmu_context
    gadgetfs: list_for_each_safe() misuse
    ocfs2: fix leaks on failure exits in module_init
    ecryptfs: make register_filesystem() the last potential failure exit
    ntfs: forgets to unregister sysctls on register_filesystem() failure
    logfs: missing cleanup on register_filesystem() failure
    jfs: mising cleanup on register_filesystem() failure
    make configfs_pin_fs() return root dentry on success
    configfs: configfs_create_dir() has parent dentry in dentry->d_parent
    configfs: sanitize configfs_create()
    ...

    Linus Torvalds
     

21 Mar, 2012

2 commits

27 Feb, 2012

1 commit

23 Feb, 2012

1 commit

  • 9f6f9af76   af_unix: MSG_TRUNC support for dgram sockets ... Browse Code »

    Piergiorgio Beruto expressed the need to fetch size of first datagram in
    queue for AF_UNIX sockets and suggested a patch against SIOCINQ ioctl.

    I suggested instead to implement MSG_TRUNC support as a recv() input
    flag, as already done for RAW, UDP & NETLINK sockets.

    len = recv(fd, &byte, 1, MSG_PEEK | MSG_TRUNC);

    MSG_TRUNC asks recv() to return the real length of the packet, even when
    is was longer than the passed buffer.

    There is risk that a userland application used MSG_TRUNC by accident
    (since it had no effect on af_unix sockets) and this might break after
    this patch.

    Signed-off-by: Eric Dumazet
    Tested-by: Piergiorgio Beruto
    CC: Michael Kerrisk
    Signed-off-by: David S. Miller

    Eric Dumazet
     

22 Feb, 2012

2 commits

  • fc0d75364   unix: Support peeking offset for stream sockets ... Browse Code »

    The same here -- we can protect the sk_peek_off manipulations with
    the unix_sk->readlock mutex.

    The peeking of data from a stream socket is done in the datagram style,
    i.e. even if there's enough room for more data in the user buffer, only
    the head skb's data is copied in there. This feature is preserved when
    peeking data from a given offset -- the data is read till the nearest
    skb's boundary.

    Signed-off-by: Pavel Emelyanov
    Acked-by: Eric Dumazet
    Signed-off-by: David S. Miller

    Pavel Emelyanov
     
  • f55bb7f9c   unix: Support peeking offset for datagram and seqpacket sockets ... Browse Code »

    The sk_peek_off manipulations are protected with the unix_sk->readlock mutex.
    This mutex is enough since all we need is to syncronize setting the offset
    vs reading the queue head. The latter is fully covered with the mentioned lock.

    The recently added __skb_recv_datagram's offset is used to pick the skb to
    read the data from.

    Signed-off-by: Pavel Emelyanov
    Acked-by: Eric Dumazet
    Signed-off-by: David S. Miller

    Pavel Emelyanov
     

31 Jan, 2012

1 commit

  • 6f01fd6e6   af_unix: fix EPOLLET regression for stream sockets ... Browse Code »

    Commit 0884d7aa24 (AF_UNIX: Fix poll blocking problem when reading from
    a stream socket) added a regression for epoll() in Edge Triggered mode
    (EPOLLET)

    Appropriate fix is to use skb_peek()/skb_unlink() instead of
    skb_dequeue(), and only call skb_unlink() when skb is fully consumed.

    This remove the need to requeue a partial skb into sk_receive_queue head
    and the extra sk->sk_data_ready() calls that added the regression.

    This is safe because once skb is given to sk_receive_queue, it is not
    modified by a writer, and readers are serialized by u->readlock mutex.

    This also reduce number of spinlock acquisition for small reads or
    MSG_PEEK users so should improve overall performance.

    Reported-by: Nick Mathewson
    Signed-off-by: Eric Dumazet
    Cc: Alexey Moiseytsev
    Signed-off-by: David S. Miller

    Eric Dumazet
     

10 Jan, 2012

1 commit

  • 38e5781bb   Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net ... Browse Code »

    * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net:
    igmp: Avoid zero delay when receiving odd mixture of IGMP queries
    netdev: make net_device_ops const
    bcm63xx: make ethtool_ops const
    usbnet: make ethtool_ops const
    net: Fix build with INET disabled.
    net: introduce netif_addr_lock_nested() and call if when appropriate
    net: correct lock name in dev_[uc/mc]_sync documentations.
    net: sk_update_clone is only used in net/core/sock.c
    8139cp: fix missing napi_gro_flush.
    pktgen: set correct max and min in pktgen_setup_inject()
    smsc911x: Unconditionally include linux/smscphy.h in smsc911x.h
    asix: fix infinite loop in rx_fixup()
    net: Default UDP and UNIX diag to 'n'.
    r6040: fix typo in use of MCR0 register bits
    net: fix sock_clone reference mismatch with tcp memcontrol

    Linus Torvalds
     

09 Jan, 2012

1 commit

  • 972b2c719   Merge branch 'for-linus2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs ... Browse Code »

    * 'for-linus2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (165 commits)
    reiserfs: Properly display mount options in /proc/mounts
    vfs: prevent remount read-only if pending removes
    vfs: count unlinked inodes
    vfs: protect remounting superblock read-only
    vfs: keep list of mounts for each superblock
    vfs: switch ->show_options() to struct dentry *
    vfs: switch ->show_path() to struct dentry *
    vfs: switch ->show_devname() to struct dentry *
    vfs: switch ->show_stats to struct dentry *
    switch security_path_chmod() to struct path *
    vfs: prefer ->dentry->d_sb to ->mnt->mnt_sb
    vfs: trim includes a bit
    switch mnt_namespace ->root to struct mount
    vfs: take /proc/*/mounts and friends to fs/proc_namespace.c
    vfs: opencode mntget() mnt_set_mountpoint()
    vfs: spread struct mount - remaining argument of next_mnt()
    vfs: move fsnotify junk to struct mount
    vfs: move mnt_devname
    vfs: move mnt_list to struct mount
    vfs: switch pnode.h macros to struct mount *
    ...

    Linus Torvalds
     

08 Jan, 2012

1 commit

04 Jan, 2012

1 commit

31 Dec, 2011

3 commits

27 Dec, 2011

2 commits

21 Dec, 2011

1 commit

  • 2ea744a58   net: unix -- Add missing module.h inclusion ... Browse Code »

    Otherwise getting

    | net/unix/diag.c:312:16: error: expected declaration specifiers or ‘...’ before string constant
    | net/unix/diag.c:313:1: error: expected declaration specifiers or ‘...’ before string constant

    Signed-off-by: Cyrill Gorcunov
    Signed-off-by: David S. Miller

    Cyrill Gorcunov
     

17 Dec, 2011

10 commits

27 Nov, 2011

1 commit

29 Sep, 2011

1 commit

  • 16e572626   af_unix: dont send SCM_CREDENTIALS by default ... Browse Code »

    Since commit 7361c36c5224 (af_unix: Allow credentials to work across
    user and pid namespaces) af_unix performance dropped a lot.

    This is because we now take a reference on pid and cred in each write(),
    and release them in read(), usually done from another process,
    eventually from another cpu. This triggers false sharing.

    # Events: 154K cycles
    #
    # Overhead Command Shared Object Symbol
    # ........ ....... .................. .........................
    #
    10.40% hackbench [kernel.kallsyms] [k] put_pid
    8.60% hackbench [kernel.kallsyms] [k] unix_stream_recvmsg
    7.87% hackbench [kernel.kallsyms] [k] unix_stream_sendmsg
    6.11% hackbench [kernel.kallsyms] [k] do_raw_spin_lock
    4.95% hackbench [kernel.kallsyms] [k] unix_scm_to_skb
    4.87% hackbench [kernel.kallsyms] [k] pid_nr_ns
    4.34% hackbench [kernel.kallsyms] [k] cred_to_ucred
    2.39% hackbench [kernel.kallsyms] [k] unix_destruct_scm
    2.24% hackbench [kernel.kallsyms] [k] sub_preempt_count
    1.75% hackbench [kernel.kallsyms] [k] fget_light
    1.51% hackbench [kernel.kallsyms] [k]
    __mutex_lock_interruptible_slowpath
    1.42% hackbench [kernel.kallsyms] [k] sock_alloc_send_pskb

    This patch includes SCM_CREDENTIALS information in a af_unix message/skb
    only if requested by the sender, [man 7 unix for details how to include
    ancillary data using sendmsg() system call]

    Note: This might break buggy applications that expected SCM_CREDENTIAL
    from an unaware write() system call, and receiver not using SO_PASSCRED
    socket option.

    If SOCK_PASSCRED is set on source or destination socket, we still
    include credentials for mere write() syscalls.

    Performance boost in hackbench : more than 50% gain on a 16 thread
    machine (2 quad-core cpus, 2 threads per core)

    hackbench 20 thread 2000

    4.228 sec instead of 9.102 sec

    Signed-off-by: Eric Dumazet
    Acked-by: Tim Chen
    Signed-off-by: David S. Miller

    Eric Dumazet
     

17 Sep, 2011

1 commit

25 Aug, 2011

1 commit

  • 0856a3040   Scm: Remove unnecessary pid & credential references in Unix socket's send and receive path ... Browse Code »

    Patch series 109f6e39..7361c36c back in 2.6.36 added functionality to
    allow credentials to work across pid namespaces for packets sent via
    UNIX sockets. However, the atomic reference counts on pid and
    credentials caused plenty of cache bouncing when there are numerous
    threads of the same pid sharing a UNIX socket. This patch mitigates the
    problem by eliminating extraneous reference counts on pid and
    credentials on both send and receive path of UNIX sockets. I found a 2x
    improvement in hackbench's threaded case.

    On the receive path in unix_dgram_recvmsg, currently there is an
    increment of reference count on pid and credentials in scm_set_cred.
    Then there are two decrement of the reference counts. Once in scm_recv
    and once when skb_free_datagram call skb->destructor function
    unix_destruct_scm. One pair of increment and decrement of ref count on
    pid and credentials can be eliminated from the receive path. Until we
    destroy the skb, we already set a reference when we created the skb on
    the send side.

    On the send path, there are two increments of ref count on pid and
    credentials, once in scm_send and once in unix_scm_to_skb. Then there
    is a decrement of the reference counts in scm_destroy's call to
    scm_destroy_cred at the end of unix_dgram_sendmsg functions. One pair
    of increment and decrement of the reference counts can be removed so we
    only need to increment the ref counts once.

    By incorporating these changes, for hackbench running on a 4 socket
    NHM-EX machine with 40 cores, the execution of hackbench on
    50 groups of 20 threads sped up by factor of 2.

    Hackbench command used for testing:
    ./hackbench 50 thread 2000

    Signed-off-by: Tim Chen
    Signed-off-by: David S. Miller

    Tim Chen
     

20 Jul, 2011

1 commit

24 May, 2011

1 commit

  • 71338aa7d   net: convert %p usage to %pK ... Browse Code »

    The %pK format specifier is designed to hide exposed kernel pointers,
    specifically via /proc interfaces. Exposing these pointers provides an
    easy target for kernel write vulnerabilities, since they reveal the
    locations of writable structures containing easily triggerable function
    pointers. The behavior of %pK depends on the kptr_restrict sysctl.

    If kptr_restrict is set to 0, no deviation from the standard %p behavior
    occurs. If kptr_restrict is set to 1, the default, if the current user
    (intended to be a reader via seq_printf(), etc.) does not have CAP_SYSLOG
    (currently in the LSM tree), kernel pointers using %pK are printed as 0's.
    If kptr_restrict is set to 2, kernel pointers using %pK are printed as
    0's regardless of privileges. Replacing with 0's was chosen over the
    default "(null)", which cannot be parsed by userland %p, which expects
    "(nil)".

    The supporting code for kptr_restrict and %pK are currently in the -mm
    tree. This patch converts users of %p in net/ to %pK. Cases of printing
    pointers to the syslog are not covered, since this would eliminate useful
    information for postmortem debugging and the reading of the syslog is
    already optionally protected by the dmesg_restrict sysctl.

    Signed-off-by: Dan Rosenberg
    Cc: James Morris
    Cc: Eric Dumazet
    Cc: Thomas Graf
    Cc: Eugene Teo
    Cc: Kees Cook
    Cc: Ingo Molnar
    Cc: David S. Miller
    Cc: Peter Zijlstra
    Cc: Eric Paris
    Signed-off-by: Andrew Morton
    Signed-off-by: David S. Miller

    Dan Rosenberg