Commit graph

15 commits

Author SHA1 Message Date
Alan Cox
01da5fd83d [PATCH] Fix tty layer DoS and comment relevant code
Unlike the other tty comment patch this one has code changes.  Specifically
it limits the queue size for a tty to 64K characters (128Kbytes) worst case
even if the tty is ignoring tty->throttle.  This is because certain drivers
don't honour the throttle value correctly, although it is a useful
safeguard anyway.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-08-27 11:01:34 -07:00
Jon Smirl
894673ee61 [PATCH] tty: Remove include of screen_info.h from tty.h
screen_info.h doesn't have anything to do with the tty layer and shouldn't be
included by tty.h.  This patches removes the include and modifies all users to
directly include screen_info.h.  struct screen_info is mainly used to
communicate with the console drivers in drivers/video/console.  Note that this
patch touches every arch and I have no way of testing it.  If there is a
mistake the worst thing that will happen is a compile error.

[akpm@osdl.org: fix arm build]
[akpm@osdl.org: fix alpha build]
Signed-off-by: Jon Smirl <jonsmir@gmail.com>
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-10 13:24:16 -07:00
Jon Smirl
a8f340e394 [PATCH] vt: Remove VT-specific declarations and definitions from tty.h
MAX_NR_CONSOLES, fg_console, want_console and last_console are more of a
function of the VT layer than the TTY one.  Moving these to vt.h and vt_kern.h
allows all of the framebuffer and VT console drivers to remove their
dependency on tty.h.

[akpm@osdl.org: fix alpha build]
Signed-off-by: Jon Smirl <jonsmir@gmail.com>
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-10 13:24:16 -07:00
Paul Fulghum
33b37a33c2 [PATCH] remove active field from tty buffer structure
Remove 'active' field from tty buffer structure.  This was added in 2.6.16
as part of a patch to make the new tty buffering SMP safe.  This field is
unnecessary with the more intelligently written flush_to_ldisc that adds
receive_room handling.

Removing this field reverts to simpler logic where the tail buffer is
always the 'active' buffer, which should not be freed by flush_to_ldisc.
(active == buffer being filled with new data)

The result is simpler, smaller, and faster tty buffer code.

Signed-off-by: Paul Fulghum <paulkf@microgate.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-28 14:59:05 -07:00
Paul Fulghum
817d6d3bce [PATCH] remove TTY_DONT_FLIP
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 <paulkf@microgate.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-28 14:59:05 -07:00
Hansjoerg Lipp
1cdcb6b43f [PATCH] TTY: return class device pointer from tty_register_device()
Let tty_register_device() return a pointer to the class device it creates.
This allows registrants to add their own sysfs files under the class
device node.

Signed-off-by: Hansjoerg Lipp <hjlipp@web.de>
Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-06-21 12:40:47 -07:00
David Woodhouse
62c4f0a2d5 Don't include linux/config.h from anywhere else in include/
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2006-04-26 12:56:16 +01:00
Ingo Molnar
70522e121a [PATCH] sem2mutex: tty
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 <mingo@elte.hu>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-23 07:38:11 -08:00
Paul Fulghum
8977d929e4 [PATCH] tty buffering stall fix
Prevent stalled processing of received data when a driver allocates tty
buffer space but does not immediately follow the allocation with more data
and a call to schedule receive tty processing.  (example: hvc_console) This
bug was introduced by the first locking patch for the new tty buffering.

Signed-off-by: Paul Fulghum <paulkf@microgate.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-10 08:13:12 -08:00
Paul Fulghum
808249ceba [PATCH] new tty buffering locking fix
Change locking in the new tty buffering facility from using tty->read_lock,
which is currently ignored by drivers and thus ineffective.  New locking
uses a new tty buffering specific lock enforced centrally in the tty
buffering code.

Two drivers (esp and cyclades) are updated to use the tty buffering
functions instead of accessing tty buffering internals directly.  This is
required for the new locking to work.

Minor checks for NULL buffers added to
tty_prepare_flip_string/tty_prepare_flip_string_flags

Signed-off-by: Paul Fulghum <paulkf@microgate.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-03 08:32:09 -08:00
Alan Cox
33f0f88f1c [PATCH] TTY layer buffering revamp
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 <alan@redhat.com>
Cc: Paul Fulghum <paulkf@microgate.com>
Signed-off-by: Hirokazu Takata <takata@linux-m32r.org>
Signed-off-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: John Hawkes <hawkes@sgi.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-10 08:01:59 -08:00
Brian Gerst
7e7f358c8f [PATCH] Split out screen_info from tty.h
This makes it possible for boot code to use screen_info without dragging in
all of tty.h.

Signed-off-by: Brian Gerst <bgerst@didntduck.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-08 20:14:05 -08:00
Antonino A. Daplas
d2d58384fc [PATCH] vesafb: Add blanking support
Add rudimentary support by manipulating the VGA registers.  However, not
all vesa modes are VGA compatible, so VGA compatiblity is checked first.
Only 2 levels are supported, powerup and powerdown.

Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-09 13:57:58 -07:00
Alexey Dobriyan
bfb07599da [PATCH] Introduce tty_unregister_ldisc()
It's a bit strange to see tty_register_ldisc call in modules' exit
functions.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-23 09:45:35 -07:00
Linus Torvalds
1da177e4c3 Linux-2.6.12-rc2
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!
2005-04-16 15:20:36 -07:00