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  1. 13 2月, 2012 3 次提交
  3. 04 6月, 2011 1 次提交
    • L
      Revert "tty: make receive_buf() return the amout of bytes received" · 55db4c64
      由 Linus Torvalds 提交于 
      This reverts commit b1c43f82.

It was broken in so many ways, and results in random odd pty issues.

It re-introduced the buggy schedule_work() in flush_to_ldisc() that can
cause endless work-loops (see commit a5660b41: "tty: fix endless
work loop when the buffer fills up").

It also used an "unsigned int" return value fo the ->receive_buf()
function, but then made multiple functions return a negative error code,
and didn't actually check for the error in the caller.

And it didn't actually work at all.  BenH bisected down odd tty behavior
to it:
  "It looks like the patch is causing some major malfunctions of the X
   server for me, possibly related to PTYs.  For example, cat'ing a
   large file in a gnome terminal hangs the kernel for -minutes- in a
   loop of what looks like flush_to_ldisc/workqueue code, (some ftrace
   data in the quoted bits further down).

   ...

   Some more data: It -looks- like what happens is that the
   flush_to_ldisc work queue entry constantly re-queues itself (because
   the PTY is full ?) and the workqueue thread will basically loop
   forver calling it without ever scheduling, thus starving the consumer
   process that could have emptied the PTY."

which is pretty much exactly the problem we fixed in a5660b41.

Milton Miller pointed out the 'unsigned int' issue.
Reported-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Reported-by: NMilton Miller <miltonm@bga.com>
Cc: Stefan Bigler <stefan.bigler@keymile.com>
Cc: Toby Gray <toby.gray@realvnc.com>
Cc: Felipe Balbi <balbi@ti.com>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      55db4c64
  5. 23 4月, 2011 1 次提交
  7. 13 4月, 2011 1 次提交
  9. 17 2月, 2011 1 次提交
  11. 08 12月, 2010 1 次提交
  13. 22 10月, 2010 1 次提交
  15. 12 10月, 2010 1 次提交
  17. 22 7月, 2010 3 次提交
  19. 27 2月, 2010 1 次提交
  21. 04 12月, 2009 1 次提交
  23. 11 6月, 2009 2 次提交
    • A
      tty: fix bluetooth scribbling on low latency flags · 7f8d09ea
      由 Alan Cox 提交于 
      Bluetooth shouldn't be doing this as most drivers don't support the flag,
furthermore it shouldn't be needed with newer buffering. This becomes rather
more visible as the locking fixes make the abuse of low_latency visible as
spew on the users console/dmesg.
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      7f8d09ea
    • A
      tty: rewrite the ldisc locking · c65c9bc3
      由 Alan Cox 提交于 
      There are several pretty much unfixable races in the old ldisc code, especially
with respect to pty behaviour and also to hangup. It's easier to rewrite the
code than simply try and patch it up.

This patch
- splits the ldisc from the tty (so we will be able to refcount it more cleanly
  later)
- introduces a mutex lock for ldisc changing on an active device
- fixes the complete mess that hangup caused
- implements hopefully correct setldisc/close/hangup locking

There are still some problems around pty pairs that have always been there but
at least it is now possible to understand the code and fix further problems.

This fixes the following known bugs
- hang up can leak ldisc references
- hang up may not call open/close on ldisc in a matched way
- pty/tty pairs can deadlock during an ldisc change
- reading the ldisc proc files can cause every ldisc to be loaded

and probably a few other of the mysterious ldisc race reports.

I'm sure it also adds the odd new one.
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      c65c9bc3
  25. 30 11月, 2008 2 次提交
    • M
      Bluetooth: Enable per-module dynamic debug messages · a418b893
      由 Marcel Holtmann 提交于 
      With the introduction of CONFIG_DYNAMIC_PRINTK_DEBUG it is possible to
allow debugging without having to recompile the kernel. This patch turns
all BT_DBG() calls into pr_debug() to support dynamic debug messages.

As a side effect all CONFIG_BT_*_DEBUG statements are now removed and
some broken debug entries have been fixed.
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>
      a418b893
    • M
      Bluetooth: Send HCI Reset command by default on device initialization · 7a9d4020
      由 Marcel Holtmann 提交于 
      The Bluetooth subsystem was not using the HCI Reset command when doing
device initialization. The Bluetooth 1.0b specification was ambiguous
on how the device firmware was suppose to handle it. Almost every device
was triggering a transport reset at the same time. In case of USB this
ended up in disconnects from the bus.

All modern Bluetooth dongles handle this perfectly fine and a lot of
them actually require that HCI Reset is sent. If not then they are
either stuck in their HID Proxy mode or their internal structures for
inquiry and paging are not correctly setup.

To handle old and new devices smoothly the Bluetooth subsystem contains
a quirk to force the HCI Reset on initialization. However maintaining
such a quirk becomes more and more complicated. This patch turns the
logic around and lets the old devices disable the HCI Reset command.

The only device where the HCI_QUIRK_NO_RESET is still needed are the
original Digianswer devices and dongles with an early CSR firmware.

CSR reported that they fixed this for version 12 firmware. The last
official release of version 11 firmware is build ID 115. The first
version 12 candidate was build ID 117.
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>
      7a9d4020
  27. 14 10月, 2008 1 次提交
  29. 18 8月, 2008 1 次提交
    • M
      [Bluetooth] Consolidate maintainers information · 63fbd24e
      由 Marcel Holtmann 提交于 
      The Bluetooth entries for the MAINTAINERS file are a little bit too
much. Consolidate them into two entries. One for Bluetooth drivers and
another one for the Bluetooth subsystem.

Also the MODULE_AUTHOR should indicate the current maintainer of the
module and actually not the original author. Fix all Bluetooth modules
to provide current maintainer information.
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>
      63fbd24e
  31. 21 7月, 2008 1 次提交
    • A
      tty: Ldisc revamp · a352def2
      由 Alan Cox 提交于 
      Move the line disciplines towards a conventional ->ops arrangement.  For
the moment the actual 'tty_ldisc' struct in the tty is kept as part of
the tty struct but this can then be changed if it turns out that when it
all settles down we want to refcount ldiscs separately to the tty.

Pull the ldisc code out of /proc and put it with our ldisc code.
Signed-off-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      a352def2
  33. 30 4月, 2008 2 次提交
  35. 13 2月, 2008 1 次提交
    • D
      hci_ldisc: fix null pointer deref · 3611f4d2
      由 David Newall 提交于 
      Arjan:

  With the help of kerneloops.org I've spotted a nice little interaction
  between the TTY layer and the bluetooth code, however the tty layer is not
  something I'm all too familiar with so I rather ask than brute-force fix the
  code incorrectly.

  The raw details are at:
  http://www.kerneloops.org/search.php?search=uart_flush_buffer

  What happens is that, on closing the bluetooth tty, the tty layer goes
  into the release_dev() function, which first does a bunch of stuff, then
  sets the file->private_data to NULL, does some more stuff and then calls the
  ldisc close function.  Which in this case, is hci_uart_tty_close().

  Now, hci_uart_tty_close() calls hci_uart_close() which clears some
  internal bit, and then calls hci_uart_flush()...  which calls back to the
  tty layers' uart_flush_buffer() function.  (in drivers/bluetooth/hci_tty.c
  around line 194) Which then WARN_ON()'s because that's not allowed/supposed
  to be called this late in the shutdown of the port....

  Should the bluetooth driver even call this flush function at all??

David:

  This seems to be what happens: Hci_uart_close() flushes using
  hci_uart_flush().  Subsequently, in hci_dev_do_close(), (one step in
  hci_unregister_dev()), hci_uart_flush() is called again.  The comment in
  uart_flush_buffer(), relating to the WARN_ON(), indicates you can't flush
  after the port is closed; which sounds reasonable.  I think hci_uart_close()
  should set hdev->flush to NULL before returning.  Hci_dev_do_close() does
  check for this.  The code path is rather involved and I'm not entirely clear
  of all steps, but I think that's what should be done.
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      3611f4d2
  37. 22 10月, 2007 1 次提交
  39. 11 5月, 2007 3 次提交
  41. 15 2月, 2007 1 次提交
    • T
      [PATCH] remove many unneeded #includes of sched.h · cd354f1a
      由 Tim Schmielau 提交于 
      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: NTim Schmielau <tim@physik3.uni-rostock.de>
Acked-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      cd354f1a
  43. 29 9月, 2006 1 次提交
  45. 13 7月, 2006 1 次提交
  47. 01 7月, 2006 1 次提交
  49. 11 1月, 2006 1 次提交
    • A
      [PATCH] TTY layer buffering revamp · 33f0f88f
      由 Alan Cox 提交于 
      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: NAlan Cox <alan@redhat.com>
Cc: Paul Fulghum <paulkf@microgate.com>
Signed-off-by: NHirokazu Takata <takata@linux-m32r.org>
Signed-off-by: NSerge Hallyn <serue@us.ibm.com>
Signed-off-by: NJeff Dike <jdike@addtoit.com>
Signed-off-by: NJohn Hawkes <hawkes@sgi.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      33f0f88f
  51. 07 11月, 2005 1 次提交
  53. 29 10月, 2005 2 次提交
  55. 30 8月, 2005 1 次提交
  57. 06 8月, 2005 1 次提交
  59. 24 6月, 2005 1 次提交