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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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Add support for Texas Instruments' HCI Low Level (HCILL) Bluetooth
protocol, which is a power management extension to H4. The HCILL is
widely used by TI's BRF63xx Bluetooth chips.
Signed-off-by: Ohad Ben-Cohen <ohad@bencohen.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
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A trivial fix to (what looks like) an unintentional fall-through in the
HCI line discipline.
Signed-off-by: Ohad Ben-Cohen <ohad@bencohen.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
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Normally a serial Bluetooth device is opened, TIOSETD'ed to N_HCI line
discipline, HCIUARTSETPROTO'ed and finally closed. In case the device
fails to HCIUARTSETPROTO, closing it produces a NULL pointer dereference.
Signed-off-by: Ohad Ben-Cohen <ohad@bencohen.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
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Adding HCIUARTGETDEVICE makes it possible to get the HCI device number
that is attached to a given serial device. This is required during the
initialization process of some Bluetooth chips.
Signed-off-by: Ohad Ben-Cohen <ohad@bencohen.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
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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 <tim@physik3.uni-rostock.de>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This patch cleans up the Bluetooth HCI UART driver a bit.
Signed-off-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
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This patch checks for tty->driver before trying to call flush_buffer().
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
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Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
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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>
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Signed-off-by: Deepak Saxena <dsaxena@plexity.net>
Cc: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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This patch contains the big cleanup of the HCI UART driver. The uneeded
header files are removed and their structure declarations are moved into
the protocol implementations.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
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The TXCRC compile option is not really useful and thus change it
into a module parameter.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
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This patch moves the usage of packet type into the SKB control
buffer. After this patch it is now possible to shrink the sk_buff
structure and redefine its pkt_type.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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This patch removes the unused bt_dump() function and it also removes
its BT_DMP macro. It also unexports the hci_dev_get(), hci_send_cmd()
and hci_si_event() functions.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
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tty_register_ldisc(N_FOO, NULL) => tty_unregister_ldisc(N_FOO)
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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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!
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