15 Feb, 2007

1 commit

  • After Al Viro (finally) succeeded in removing the sched.h #include in module.h
    recently, it makes sense again to remove other superfluous sched.h includes.
    There are quite a lot of files which include it but don't actually need
    anything defined in there. Presumably these includes were once needed for
    macros that used to live in sched.h, but moved to other header files in the
    course of cleaning it up.

    To ease the pain, this time I did not fiddle with any header files and only
    removed #includes from .c-files, which tend to cause less trouble.

    Compile tested against 2.6.20-rc2 and 2.6.20-rc2-mm2 (with offsets) on alpha,
    arm, i386, ia64, mips, powerpc, and x86_64 with allnoconfig, defconfig,
    allmodconfig, and allyesconfig as well as a few randconfigs on x86_64 and all
    configs in arch/arm/configs on arm. I also checked that no new warnings were
    introduced by the patch (actually, some warnings are removed that were emitted
    by unnecessarily included header files).

    Signed-off-by: Tim Schmielau
    Acked-by: Russell King
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Tim Schmielau
     

09 Dec, 2006

1 commit

  • 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
     

02 Oct, 2006

1 commit

  • As part of an SMP cleanliness pass over UML, I consted a bunch of
    structures in order to not have to document their locking. One of these
    structures was a struct tty_operations. In order to const it in UML
    without introducing compiler complaints, the declaration of
    tty_set_operations needs to be changed, and then all of its callers need to
    be fixed.

    This patch declares all struct tty_operations in the tree as const. In all
    cases, they are static and used only as input to tty_set_operations. As an
    extra check, I ran an i386 allyesconfig build which produced no extra
    warnings.

    53 drivers are affected. I checked the history of a bunch of them, and in
    most cases, there have been only a handful of maintenance changes in the
    last six months. serial_core.c was the busiest one that I looked at.

    Signed-off-by: Jeff Dike
    Acked-by: Alan Cox
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Jeff Dike
     

01 Jul, 2006

1 commit


30 Jun, 2006

1 commit

  • * git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/devfs-2.6: (22 commits)
    [PATCH] devfs: Remove it from the feature_removal.txt file
    [PATCH] devfs: Last little devfs cleanups throughout the kernel tree.
    [PATCH] devfs: Rename TTY_DRIVER_NO_DEVFS to TTY_DRIVER_DYNAMIC_DEV
    [PATCH] devfs: Remove the tty_driver devfs_name field as it's no longer needed
    [PATCH] devfs: Remove the line_driver devfs_name field as it's no longer needed
    [PATCH] devfs: Remove the videodevice devfs_name field as it's no longer needed
    [PATCH] devfs: Remove the gendisk devfs_name field as it's no longer needed
    [PATCH] devfs: Remove the miscdevice devfs_name field as it's no longer needed
    [PATCH] devfs: Remove the devfs_fs_kernel.h file from the tree
    [PATCH] devfs: Remove devfs_remove() function from the kernel tree
    [PATCH] devfs: Remove devfs_mk_cdev() function from the kernel tree
    [PATCH] devfs: Remove devfs_mk_bdev() function from the kernel tree
    [PATCH] devfs: Remove devfs_mk_symlink() function from the kernel tree
    [PATCH] devfs: Remove devfs_mk_dir() function from the kernel tree
    [PATCH] devfs: Remove devfs_*_tape() functions from the kernel tree
    [PATCH] devfs: Remove devfs support from the sound subsystem
    [PATCH] devfs: Remove devfs support from the ide subsystem.
    [PATCH] devfs: Remove devfs support from the serial subsystem
    [PATCH] devfs: Remove devfs from the init code
    [PATCH] devfs: Remove devfs from the partition code
    ...

    Linus Torvalds
     

29 Jun, 2006

1 commit

  • 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
     

27 Jun, 2006

4 commits


11 Jan, 2006

1 commit

  • 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
     

10 Sep, 2005

1 commit

  • The idea of this patch is to lock both sides of a ptmx/pty pair during line
    discipline changing. This is needed to ensure that say a poll on one side of
    the pty doesn't occur while the line discipline is actively being changed.
    This resulted in an oops reported on lkml, see:

    http://marc.theaimsgroup.com/?l=linux-kernel&m=111342171410005&w=2

    A 'hacky' approach was previously implmemented which served to eliminate the
    poll vs. line discipline changing race. However, this patch takes a more
    general approach to the issue. The patch only adds locking on a less often
    used path, the line-discipline changing path, as opposed to locking the
    ptmx/pty pair on read/write/poll paths.

    The patch below, takes both ldisc locks in either order b/c the locks are both
    taken under the same spinlock(). I thought about locking the ptmx/pty
    separately, such as master always first but that introduces a 3 way deadlock.
    For example, process 1 does a blocking read on the slave side. Then, process
    2 does an ldisc change on the slave side, which acquires the master ldisc lock
    but not the slave's. Finally, process 3 does a write which blocks on the
    process 2's ldisc reference.

    This patch does introduce some changes in semantics. For example, a line
    discipline change on side 'a' of a ptmx/pty pair, will now wait for a
    read/write to complete on the other side, or side 'b'. The current behavior
    is to simply wait for any read/writes on only side 'a', not both sides 'a' and
    'b'. I think this behavior makes sense, but I wanted to point it out.

    I've tested the patch with a bunch of read/write/poll while changing the line
    discipline out from underneath.

    This patch obviates the need for the above "hide the problem" patch.

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

    Jason Baron
     

17 Apr, 2005

1 commit

  • 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