Eric Lee / smarc-fsl-linux-kernel

17 Jul, 2007

1 commit

01 Jun, 2007

1 commit

  • 040b6362d   tty: fix leakage of -ERESTARTSYS to userland ... Browse Code »

    Spotted by Satoru Takeuchi.

    kill_pgrp(task_pgrp(current)) sends the signal to the current's thread
    group, but can choose any sub-thread as a target for signal_wake_up().
    This means that job_control() and tty_check_change() may return
    -ERESTARTSYS without signal_pending().

    Signed-off-by: Oleg Nesterov
    Cc: Satoru Takeuchi
    Cc: Roland McGrath
    Cc: Alan Cox
    Cc:
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Oleg Nesterov
     

11 May, 2007

1 commit

  • e10cc1df1   tty: add compat_ioctl ... Browse Code »

    Add compat_ioctl method for tty code to allow processing of 32 bit ioctl
    calls on 64 bit systems by tty core, tty drivers, and line disciplines.

    Based on patch by Arnd Bergmann:
    http://www.uwsg.iu.edu/hypermail/linux/kernel/0511.0/1732.html

    [akpm@linux-foundation.org: make things static]
    Signed-off-by: Paul Fulghum
    Acked-by: Arnd Bergmann
    Cc: Alan Cox
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Paul Fulghum
     

13 Feb, 2007

2 commits

  • ab521dc0f   [PATCH] tty: update the tty layer to work with struct pid ... Browse Code »

    Of kernel subsystems that work with pids the tty layer is probably the largest
    consumer. But it has the nice virtue that the assiation with a session only
    lasts until the session leader exits. Which means that no reference counting
    is required. So using struct pid winds up being a simple optimization to
    avoid hash table lookups.

    In the long term the use of pid_nr also ensures that when we have multiple pid
    spaces mixed everything will work correctly.

    Signed-off-by: Eric W. Biederman
    Cc: Alan Cox
    Cc: Oleg Nesterov
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Eric W. Biederman
     
  • 3e7cd6c41   [PATCH] pid: replace is_orphaned_pgrp with is_current_pgrp_orphaned ... Browse Code »

    Every call to is_orphaned_pgrp passed in process_group(current) which is racy
    with respect to another thread changing our process group. It didn't bite us
    because we were dealing with integers and the worse we would get would be a
    stale answer.

    In switching the checks to use struct pid to be a little more efficient and
    prepare the way for pid namespaces this race became apparent.

    So I simplified the calls to the more specialized is_current_pgrp_orphaned so
    I didn't have to worry about making logic changes to avoid the race.

    Signed-off-by: Eric W. Biederman
    Cc: Alan Cox
    Cc: Oleg Nesterov
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Eric W. Biederman
     

14 Dec, 2006

1 commit

09 Dec, 2006

1 commit

  • 606d099cd   [PATCH] tty: switch to ktermios ... Browse Code »

    This is the grungy swap all the occurrences in the right places patch that
    goes with the updates. At this point we have the same functionality as
    before (except that sgttyb() returns speeds not zero) and are ready to
    begin turning new stuff on providing nobody reports lots of bugs

    If you are a tty driver author converting an out of tree driver the only
    impact should be termios->ktermios name changes for the speed/property
    setting functions from your upper layers.

    If you are implementing your own TCGETS function before then your driver
    was broken already and its about to get a whole lot more painful for you so
    please fix it 8)

    Also fill in c_ispeed/ospeed on init for most devices, although the current
    code will do this for you anyway but I'd like eventually to lose that extra
    paranoia

    [akpm@osdl.org: bluetooth fix]
    [mp3@de.ibm.com: sclp fix]
    [mp3@de.ibm.com: warning fix for tty3270]
    [hugh@veritas.com: fix tty_ioctl powerpc build]
    [jdike@addtoit.com: uml: fix ->set_termios declaration]
    Signed-off-by: Alan Cox
    Signed-off-by: Martin Peschke
    Acked-by: Peter Oberparleiter
    Cc: Cornelia Huck
    Signed-off-by: Hugh Dickins
    Signed-off-by: Jeff Dike
    Cc: Paolo 'Blaisorblade' Giarrusso
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Alan Cox
     

29 Jun, 2006

1 commit

  • 817d6d3bc   [PATCH] remove TTY_DONT_FLIP ... Browse Code »

    Remove TTY_DONT_FLIP tty flag. This flag was introduced in 2.1.X kernels
    to prevent the N_TTY line discipline functions read_chan() and
    n_tty_receive_buf() from running at the same time. 2.2.15 introduced
    tty->read_lock to protect access to the N_TTY read buffer, which is the
    only state requiring protection between these two functions.

    The current TTY_DONT_FLIP implementation is broken for SMP, and is not
    universally honored by drivers that send data directly to the line
    discipline receive_buf function.

    Because TTY_DONT_FLIP is not necessary, is broken in implementation, and is
    not universally honored, it is removed.

    Signed-off-by: Paul Fulghum
    Cc: Alan Cox
    Cc: Theodore Ts'o
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Paul Fulghum
     

12 Jun, 2006

1 commit

  • 289a1e995   [PATCH] Fix for the PPTP hangs that have been reported ... Browse Code »

    People have been reporting that PPP connections over ptys, such as
    used with PPTP, will hang randomly when transferring large amounts of
    data, for instance in http://bugzilla.kernel.org/show_bug.cgi?id=6530.
    I have managed to reproduce the problem, and the patch below fixes the
    actual cause.

    The problem is not in fact in ppp_async.c but in n_tty.c. What
    happens is that when pptp reads from the pty, we call read_chan() in
    drivers/char/n_tty.c on the master side of the pty. That copies all
    the characters out of its buffer to userspace and then calls
    check_unthrottle(), which calls the pty unthrottle routine, which
    calls tty_wakeup on the slave side, which calls ppp_asynctty_wakeup,
    which calls tasklet_schedule. So far so good. Since we are in
    process context, the tasklet runs immediately and calls
    ppp_async_process(), which calls ppp_async_push, which calls the
    tty->driver->write function to send some more output.

    However, tty->driver->write() returns zero, because the master
    tty->receive_room is still zero. We haven't returned from
    check_unthrottle() yet, and read_chan() only updates tty->receive_room
    _after_ calling check_unthrottle. That means that the driver->write
    call in ppp_async_process() returns 0. That would be fine if we were
    going to get a subsequent wakeup call, but we aren't (we just had it,
    and the buffer is now empty).

    The solution is for n_tty.c to update tty->receive_room _before_
    calling the driver unthrottle routine. The patch below does this.
    With this patch I was able to transfer a 900MB file over a PPTP
    connection (taking about 25 minutes), whereas without the patch the
    connection would always stall in under a minute.

    Signed-off-by: Paul Mackerras
    Signed-off-by: Linus Torvalds

    Paul Mackerras
     

23 Mar, 2006

1 commit

  • 70522e121   [PATCH] sem2mutex: tty ... Browse Code »

    Semaphore to mutex conversion.

    The conversion was generated via scripts, and the result was validated
    automatically via a script as well.

    Signed-off-by: Ingo Molnar
    Cc: Alan Cox
    Cc: Russell King
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Ingo Molnar
     

11 Jan, 2006

1 commit

  • 33f0f88f1   [PATCH] TTY layer buffering revamp ... Browse Code »

    The API and code have been through various bits of initial review by
    serial driver people but they definitely need to live somewhere for a
    while so the unconverted drivers can get knocked into shape, existing
    drivers that have been updated can be better tuned and bugs whacked out.

    This replaces the tty flip buffers with kmalloc objects in rings. In the
    normal situation for an IRQ driven serial port at typical speeds the
    behaviour is pretty much the same, two buffers end up allocated and the
    kernel cycles between them as before.

    When there are delays or at high speed we now behave far better as the
    buffer pool can grow a bit rather than lose characters. This also means
    that we can operate at higher speeds reliably.

    For drivers that receive characters in blocks (DMA based, USB and
    especially virtualisation) the layer allows a lot of driver specific
    code that works around the tty layer with private secondary queues to be
    removed. The IBM folks need this sort of layer, the smart serial port
    people do, the virtualisers do (because a virtualised tty typically
    operates at infinite speed rather than emulating 9600 baud).

    Finally many drivers had invalid and unsafe attempts to avoid buffer
    overflows by directly invoking tty methods extracted out of the innards
    of work queue structs. These are no longer needed and all go away. That
    fixes various random hangs with serial ports on overflow.

    The other change in here is to optimise the receive_room path that is
    used by some callers. It turns out that only one ldisc uses receive room
    except asa constant and it updates it far far less than the value is
    read. We thus make it a variable not a function call.

    I expect the code to contain bugs due to the size alone but I'll be
    watching and squashing them and feeding out new patches as it goes.

    Because the buffers now dynamically expand you should only run out of
    buffering when the kernel runs out of memory for real. That means a lot of
    the horrible hacks high performance drivers used to do just aren't needed any
    more.

    Description:

    tty_insert_flip_char is an old API and continues to work as before, as does
    tty_flip_buffer_push() [this is why many drivers dont need modification]. It
    does now also return the number of chars inserted

    There are also

    tty_buffer_request_room(tty, len)

    which asks for a buffer block of the length requested and returns the space
    found. This improves efficiency with hardware that knows how much to
    transfer.

    and tty_insert_flip_string_flags(tty, str, flags, len)

    to insert a string of characters and flags

    For a smart interface the usual code is

    len = tty_request_buffer_room(tty, amount_hardware_says);
    tty_insert_flip_string(tty, buffer_from_card, len);

    More description!

    At the moment tty buffers are attached directly to the tty. This is causing a
    lot of the problems related to tty layer locking, also problems at high speed
    and also with bursty data (such as occurs in virtualised environments)

    I'm working on ripping out the flip buffers and replacing them with a pool of
    dynamically allocated buffers. This allows both for old style "byte I/O"
    devices and also helps virtualisation and smart devices where large blocks of
    data suddenely materialise and need storing.

    So far so good. Lots of drivers reference tty->flip.*. Several of them also
    call directly and unsafely into function pointers it provides. This will all
    break. Most drivers can use tty_insert_flip_char which can be kept as an API
    but others need more.

    At the moment I've added the following interfaces, if people think more will
    be needed now is a good time to say

    int tty_buffer_request_room(tty, size)

    Try and ensure at least size bytes are available, returns actual room (may be
    zero). At the moment it just uses the flipbuf space but that will change.
    Repeated calls without characters being added are not cumulative. (ie if you
    call it with 1, 1, 1, and then 4 you'll have four characters of space. The
    other functions will also try and grow buffers in future but this will be a
    more efficient way when you know block sizes.

    int tty_insert_flip_char(tty, ch, flag)

    As before insert a character if there is room. Now returns 1 for success, 0
    for failure.

    int tty_insert_flip_string(tty, str, len)

    Insert a block of non error characters. Returns the number inserted.

    int tty_prepare_flip_string(tty, strptr, len)

    Adjust the buffer to allow len characters to be added. Returns a buffer
    pointer in strptr and the length available. This allows for hardware that
    needs to use functions like insl or mencpy_fromio.

    Signed-off-by: Alan Cox
    Cc: Paul Fulghum
    Signed-off-by: Hirokazu Takata
    Signed-off-by: Serge Hallyn
    Signed-off-by: Jeff Dike
    Signed-off-by: John Hawkes
    Signed-off-by: Martin Schwidefsky
    Signed-off-by: Adrian Bunk
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Alan Cox
     

28 Oct, 2005

1 commit

11 Sep, 2005

1 commit

08 Jul, 2005

1 commit

  • d6afe27bf   [PATCH] tty output lossage fix ... Browse Code »

    The patch fixes a few corner cases around tty line editing with
    very long input lines:

    - n_tty_receive_char(): don't simply drop eol characters,
    otherwise canon_data isn't increased and the reader isn't woken
    up.

    - n_tty_receive_room(): If there is no newline pending and the
    edit buffer is full, allow only a single character to be written
    (until eol is found and the line is flushed), so characters from
    the next line aren't dropped.

    - write_chan(): if an incomplete line was written, continue
    writing until write() returns 0, otherwise it might not write
    the eol character to flush the line and the writer goes to sleep
    without ever being woken up.

    BTW the core problem is that part of this should be handled in the
    receive_buf path, but for this it has to return the number of
    written characters, as the amount of written characters may not be
    the same as the amount of characters going into the write buffer,
    so the receive_room() usage in pty_write() is not really reliable.

    Alan said:

    The problem looks valid. The behaviour of 'traditional unix' appears to
    be the following

    If you exceed the line limit then beep and drop the character
    Always allow EOL to complete a canonical line input
    Always do signal/control processing if enabled

    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Roman Zippel
     

17 Apr, 2005

1 commit

  • 1da177e4c   Linux-2.6.12-rc2 ... Browse Code »

    Initial git repository build. I'm not bothering with the full history,
    even though we have it. We can create a separate "historical" git
    archive of that later if we want to, and in the meantime it's about
    3.2GB when imported into git - space that would just make the early
    git days unnecessarily complicated, when we don't have a lot of good
    infrastructure for it.

    Let it rip!

    Linus Torvalds