| Age | Commit message (Collapse) | Author |
|---|
|
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>
|
|
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>
|
|
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>
|
|
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>
|
|
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>
|
|
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>
|
|
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>
|
|
Instead, tty_io.c will always copy user space data to
kernel space, leaving the drivers to worry only about
normal kernel buffers.
No more "from_user" flag, and having the user copy in
each driver.
This cleans up the code and also fixes a number of
locking bugs.
|
|
This makes the agreed change of termios locking to be semaphore based
sleep locking. This is needed for USB in particular as it has to use
messaging to issue terminal mode changes.
This code passes Torvalds test grades 0, 1 and 2 (it looks ok, it
compiles and it booted). It does mean that a driver cannot take an
atomic peek at termios data during an interrupt. Nobody seems to be
doing this although some of the driver receive paths for line
disciplines will eventually want to (n_tty currently doesn't do this
locked on the receive path). Since the ldisc is given a chance to copy
any essential bits on the ->set_termios path this seems not to be a
problem.
|
|
No problems reported other than Linus typo in an unbuildable driver from
the last one.
This one adds tty_ldisc_flush and also makes tty_wakeup do the queue
wake as discussed with Paul. I've then propagated these functions
through all the drivers. This means most drivers don't know about the
ldisc locking and instead call generic functions that look after it.
The result is the removal of a lot of duplicate code both for ldisc
referencing and historical code for handling tty ldisc wakeup semantics.
A nice side effect is that by adding versions of the two helpers we can
switch most of the drivers over before changing the core tty code if
preferred.
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
|
|
From: Ralf Baechle <ralf@linux-mips.org>
The RM200's onboard video really is a plain old boring Cyrix PCI card.
|
|
The race is that con_close() can sleep, and drops the BKL while
tty->count==1. But another thread can come into init_dev() and will take a
new ref against the tty and start using it.
But con_close() doesn't notice that new ref and proceeds to null out
tty->driver_data while someone else is using the resurrected tty.
So the patch serialises con_close() against init_dev() with tty_sem.
Here's a test app which reproduced the oops instantly on 2-way. It realy
needs to be run against all tty-capable devices.
/*
* Run this against a tty which nobody currently has open, such as /dev/tty9
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <linux/kd.h>
void doit(char *filename)
{
int fd,x;
fd = open(filename, O_RDWR);
if (fd < 0) {
perror("open");
exit(1);
}
ioctl(fd, KDKBDREP, &x);
close(fd);
}
main(int argc, char *argv[])
{
char *filename = argv[1];
for ( ; ; )
doit(filename);
}
|
|
This sounds like a good moment to come with this patch.
This is essentially a five-year-old patch by Bruno Haible. It
introduces utf8 mode, and the effect it has on erasing input characters.
(Side note - without stty support, this is not very useful, but now
the infrastructure is in place)
|
|
From: "H. Peter Anvin" <hpa@transmeta.com>
Remove the limit of 2048 pty's - allocate them on demand up to the 12:20
dev_t limit: a million.
|
|
From: Christoph Hellwig <hch@lst.de>
All drivers that compile on ppc with CONFIG_ISA set (= all but
some m68-only drivers), I looked at the compile warnings very
closely and there are no new warnings or even errors this time :)
drivers/char/Makefile needed to be reordered big time to keep
the intialization order the same.
|
|
tty->device had been used only in a couple of places and can be
calculated by tty->index and tty->driver. Field removed, its users switched
to static inline dev_t tty_devnum(tty).
|
|
From: Christoph Hellwig <hch@lst.de>
keeping init order the same..
|
|
tty_paranoia_check() switched from kdev_t to struct inode.
|
|
From: Gerd Knorr <kraxel@suse.de>
The patch below fixes some vesafb issues. Changes:
* fixed struct screen_info in tty.h to use portable types. "unsigned
long" for 32bit values doesn't work on hammer machines ...
* limited the framebuffer memory used by vesafb to 16 MB. This avoids
that vesafb's ioremap() eats plenty of kernel address space for no real
benefit if the gfx card has very much memory (some have 128 MB or more,
ia32 has 128 MB address space for vmalloc and ioremap ...).
* mtrr is enabled by default. That should improve the vesafb performance
a lot. Also added a option to disable mtrr.
|
|
From: Pavel Machek <pavel@ucw.cz>
This fixes url in ioctls, fixes some kernel parameters, kills comment
in tty that is 10+ years old and wrong, and adds me a little
credits.
|
|
This fixes the TIOCCONS race; it's the same as the 2.4 patch except for
a fix for a brown-paperbag bug in it.
|
|
|
|
tty->device switched to dev_t
There are very few uses of tty->device left by now; most of
them actually want dev_t (process accounting, proc/<pid>/stat, several
ioctls, slip.c logics, etc.) and the rest will go away shortly.
|
|
sanitized driver->driver_name initialization and use
|
|
tty->tty_index added; we initialize it with minor(tty->device) -
tty->driver->minor_start. Majority of remaining tty->device uses had
that form and are switched to use of tty->index.
|
|
new field - tty->tty_name;
initialized to <driver->name><tty index+driver->base_name>
when we allocate tty_struct. Drivers code switched to use of that
beast (in debugging printks, mostly). Large, but trivial.
|
|
Instead of copying tty_driver into tty_struct we put a reference
in there. tty->driver turned into a pointer, users updated. Large, but
trivial
|
|
|
|
Many places use inappropriate types for comparing jiffies,
int for example. Fix those places up.
|
|
Also got rid of the unused flag paramater.
|
|
Currently, uart_get_divisor() and uart_get_baud_rate() take a tty
structure. We really want them to take a termios structure so we
can avoid passing a tty structure all the way down to the low level
drivers.
In order to do this, we need to be able to convert a termios
structure to a numeric baud rate - we provide tty_termios_baud_rate() in
tty_io.c for this purpose. It performs a subset of the
tty_get_baud_rate() functionality, but without any "alt_speed"
kludge.
We finally export uart_get_baud_rate() and uart_get_divisor() to for
low level drivers to use. We now have all the functions in place
to support ports which want to have access to the real baud rate
rather than a divisor value.
|
|
This is the next iteration of the workqueue abstraction.
The framework includes:
- per-CPU queueing support.
on SMP there is a per-CPU worker thread (bound to its CPU) and per-CPU
work queues - this feature is completely transparent to workqueue-users.
keventd automatically uses this feature. XFS can now update to work-queues
and have the same per-CPU performance as it had with its per-CPU worker
threads.
- delayed work submission
there's a new queue_delayed_work(wq, work, delay) function and a new
schedule_delayed_work(work, delay) function. The later one is used to
correctly fix former tq_timer users. I've reverted those changes in 2.5.40
that changed tq_timer uses to schedule_work() - eg. in the case of
random.c or the tty flip queue it was definitely the wrong thing to do.
delayed work means a timer embedded in struct work_struct. I considered
using split struct work_struct and delayed_work_struct types, but lots
of code actively uses task-queues in both delayed and non-delayed mode,
so i went for the more generic approach that allows both methods of work
submission. Delayed timers do not cause any other overhead in the
normal submission path otherwise.
- multithreaded run_workqueue() implementation
the run_workqueue() function can now be called from multiple contexts, and
a worker thread will only use up a single entryy - this property is used
by the flushing code, and can potentially be used in the future to extend
the number of per-CPU worker threads.
- more reliable flushing
there's now a 'pending work' counter, which is used to accurately detect
when the last work-function has finished execution. It's also used to
correctly flush against timed requests. I'm not convinced whether the old
keventd implementation got this detail right.
- i switched the arguments of the queueing function(s) per Jeff's
suggestion, it's more straightforward this way.
Driver fixes:
i have converted almost every affected driver to the new framework. This
cleaned up tons of code. I also fixed a number of drivers that were still
using BHs (these drivers did not compile in 2.5.40).
while this means lots of changes, it might ease the QA decision whether to
put this patch into 2.5.
The pach converts roughly 80% of all tqueue-using code to workqueues - and
all the places that are not converted to workqueues yet are places that do
not compile in vanilla 2.5.40 anyway, due to unrelated changes. I've
converted a fair number of drivers that do not compile in 2.5.40, and i
think i've managed to convert every driver that compiles under 2.5.40.
|
|
|
|
- merge with Alan (USB, zoran, sony motion-eye, rio, dmi-scan)
|
|
- more bugs found by the automatic stanford checker, yay!
- Andrew Morton: fix SAK locking bugs by moving it into a process context
- Johannes Erdfelt: USB updates
- Jeff Garzik: merge Hermes driver by David Gibson
- Jens Axboe: cdrom merges, ll_rw_blk proper accounting
|
|
|
