Commit Graph

29 Commits

Author SHA1 Message Date
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
Ralf Baechle
c1854ebc7f [AX25] mkiss: Drop spinlock before sleeping call.
With the previous missing-unlock fix the spinlock is dropped only
after the tty->driver->write() call which might sleep.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-09 14:16:21 -08:00
Francois Romieu
b341387225 [AX25/MKISS]: unbalanced spinlock_bh in ax_encaps()
The unlocking disappeared during commit
5793f4be23.

Signed-off-by: Francois Romieu <romieu@fr.zoreil.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-07 12:57:40 -08:00
Adrian Bunk
e6b365f61e [PATCH] drivers/net/hamradio/dmascc.c: remove dmascc_setup()
It seems dmascc_setup() is a leftover time before dmascc_init() was
there.

Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2005-11-05 21:00:01 -05:00
Jesper Juhl
b4558ea93d drivers/net: Remove pointless checks for NULL prior to calling kfree() 2005-10-28 16:53:13 -04:00
Ralf Baechle
ab7a435a01 [PATCH] Remove unused header.
mkiss.h has been integrated into mkiss.c earlier.

Signed-off-by: Ralf Baechle DL5RB <ralf@linux-mips.org>

 drivers/net/hamradio/mkiss.h |   62 -------------------------------------------
 1 files changed, 62 deletions(-)
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
2005-10-19 22:14:20 -04:00
Ralf Baechle
74cfe03f80 [PATCH] Initialize the .owner field the tty_ldisc structure.
If .owner isn't set the module can be unloaded even while still active.

Signed-off-by: Ralf Baechle DL5RB <ralf@linux-mips.org>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
2005-10-18 17:03:28 -04:00
Ralf Baechle
5793f4be23 [PATCH] SMACK support for mkiss
SMACK (Stuttgart Modified Amateurradio CRC KISS) is a KISS variant that
uses CRC16 checksums to secure data transfers between the modem and host.
It's also used to communicate over a pty to applications such as Wampes.

Patches for Linux 2.4 by Thomas Osterried DL9SAU, upgraded to the latest
mkiss 2.6 mkiss driver by me.

Signed-off-by: Thomas Osterried DL9SAU <thomas@x-berg.in-berlin.de>
Signed-off-by: Ralf Baechle DL5RB <ralf@linux-mips.org>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
2005-10-18 17:02:14 -04:00
Ralf Baechle
bc0a743860 [PATCH] rcu in bpqether driver.
From Suzanne Wood <suzannew@cs.pdx.edu>:

Clarify RCU implementation in bpqether.c.

Because bpq_new_device() calls list_add_rcu() and bpq_free_device() calls
list_del_rcu(), substitute list_for_each_entry_rcu() for
list_for_each_entry() in bpq_get_ax25_dev() and in bpq_seq_start().

Add rcu dereference protection in bpq_seq_next().

The rcu_read_lock()/unlock() in bpq_device_event() are removed because
netdev event handlers are called with RTNL locking in place.

FYI: bpq_free_device() calls list_del_rcu() which, per list.h, requires
synchronize_rcu() which can block or call_rcu() or call_rcu_bh() which
cannot block.  Herbert Xu notes that synchronization is done here by
unregister_netdevice().  This calls synchronize_net() which in turn uses
synchronize_rcu().

Signed-off-by: Ralf Baechle DL5RB <ralf@linux-mips.org>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
2005-10-18 17:01:27 -04:00
Ralf Baechle
d591958626 [PATCH] AX.25: Convert mkiss.c to DEFINE_RWLOCK
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Ralf Baechle DL5RB <ralf@linux-mips.org>

 drivers/net/hamradio/mkiss.c |    2 +-
 1 files changed, 1 insertion(+), 1 deletion(-)
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
2005-10-04 07:42:22 -04:00
Ralf Baechle
96eb549c0c [PATCH] AX.25: Delete debug printk from mkiss driver
Signed-off-by: Ralf Baechle DL5RB <ralf@linux-mips.org>

--

 drivers/net/hamradio/mkiss.c |    1 -
 1 files changed, 1 deletion(-)
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
2005-10-04 07:42:21 -04:00
Ralf Baechle
6f74998e5c [AX.25]: Rename ax25_encapsulate to ax25_hard_header
Rename ax25_encapsulate to ax25_hard_header which these days more
accurately describes what the function is supposed to do.

Signed-off-by: Ralf Baechle DL5RB <ralf@linux-mips.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-09-12 14:21:01 -07:00
Ralf Baechle
c4bc7ee2e4 [HAMRADIO]: driver cleanups
Misc related cleanups in hamradio drivers:

 o Use symbolic constants instead of magic numbers
 o Don't try to handle the case where AX.25 isn't configured - the kernel
   configuration doesn't permit that.
 o Remove useless headers

Signed-off-by: Ralf Baechle DL5RB <ralf@linux-mips.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-09-12 14:19:26 -07:00
Ingo Molnar
8d06afab73 [PATCH] timer initialization cleanup: DEFINE_TIMER
Clean up timer initialization by introducing DEFINE_TIMER a'la
DEFINE_SPINLOCK.  Build and boot-tested on x86.  A similar patch has been
been in the -RT tree for some time.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-09 14:03:48 -07:00
David S. Miller
f2ccd8fa06 [NET]: Kill skb->real_dev
Bonding just wants the device before the skb_bond()
decapsulation occurs, so simply pass that original
device into packet_type->func() as an argument.

It remains to be seen whether we can use this same
exact thing to get rid of skb->input_dev as well.

Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-29 15:32:25 -07:00
Linus Torvalds
3d963f5bb1 Merge refs/heads/upstream from master.kernel.org:/pub/scm/linux/kernel/git/jgarzik/netdev-2.6 2005-08-29 10:04:37 -07:00
Ralf Baechle
815f62bf74 [PATCH] SMP rewrite of mkiss
Rewrite the mkiss driver to make it SMP-proof following the example of
6pack.c.

Signed-off-by: Ralf Baechle DL5RB <ralf@linux-mips.org>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
2005-08-27 04:35:31 -04:00
Ralf Baechle
214838a210 [PATCH] Fix 6pack setting of MAC address
Don't check type of sax25_family; dev_set_mac_address has already done
that before and anyway, the type to check against would have been
ARPHRD_AX25.  We only got away because AF_AX25 and ARPHRD_AX25 both happen
to be defined to the same value.

Don't check sax25_ndigis either; it's value is insignificant for the
purpose of setting the MAC address and the check has shown to break
some application software for no good reason.

Signed-off-by: Ralf Baechle DL5RB <ralf@linux-mips.org>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
2005-08-27 04:32:39 -04:00
Ralf Baechle
84a2ea1c2c [PATCH] 6pack Timer initialization
I dropped the timer initialization bits by accident when sending the
p-persistence fix.  This patch gets the driver to work again on halfduplex
links.

Signed-off-by: Ralf Baechle DL5RB <ralf@linux-mips.org>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
2005-08-27 04:32:39 -04:00
Jeff Garzik
cd04b947bc Merge /spare/repo/linux-2.6/ 2005-08-11 00:07:03 -04:00
Ralf Baechle DL5RB
c0438174e8 [PATCH] 6pack persistence fix
Fix the p-persistence CSMA algorithm which in simplex mode was starting
with a slottime delay before doing anything else as if there was carrier
collision resulting in bad performance on simplex links.

Signed-off-by: Ralf Baechle DL5RB <ralf@linux-mips.org>
Acked-by: Jeff Garzik <jgarzik@pobox.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-08-10 11:03:02 -07:00
Ralf Baechle
e064cd7e3a [PATCH] SMP fix for 6pack driver
Drivers really only work well in SMP if they actually can be selected.
This is a leftover from the time when the 6pack drive only used to be
a bitrotten variant of the slip driver.

Signed-off-by: Ralf Baechle DL5RB <ralf@linux-mips.org>

 Kconfig |    2 +-
 1 files changed, 1 insertion(+), 1 deletion(-)
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
2005-07-31 01:07:41 -04:00
Marcelo Feitoza Parisi
cd8749b4aa [PATCH] Use time_before in hamradio drivers
Use of time_before() macro, defined at linux/jiffies.h, which deal with
wrapping correctly and are nicer to read.

Signed-off-by: Marcelo Feitoza Parisi <marcelo@feitoza.com.br>
Signed-off-by: Domen Puncer <domen@coderock.org>
Signed-off-by: Ralf Baechle DL5RB <ralf@linux-mips.org>

 baycom_epp.c     |    3 ++-
 baycom_par.c     |    3 ++-
 baycom_ser_fdx.c |    3 ++-
 baycom_ser_hdx.c |    3 ++-
 mkiss.c          |    3 ++-
 5 files changed, 10 insertions(+), 5 deletions(-)
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
2005-07-31 00:51:49 -04:00
David S. Miller
b03efcfb21 [NET]: Transform skb_queue_len() binary tests into skb_queue_empty()
This is part of the grand scheme to eliminate the qlen
member of skb_queue_head, and subsequently remove the
'list' member of sk_buff.

Most users of skb_queue_len() want to know if the queue is
empty or not, and that's trivially done with skb_queue_empty()
which doesn't use the skb_queue_head->qlen member and instead
uses the queue list emptyness as the test.

Signed-off-by: David S. Miller <davem@davemloft.net>
2005-07-08 14:57:23 -07:00
Alexey Dobriyan
64ccd715d3 [PATCH] Convert users to tty_unregister_ldisc()
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>
2005-06-23 09:45:36 -07:00
Adrian Bunk
0fd56f6789 [PATCH] drivers/net/hamradio/baycom_epp.c: cleanups
The times when tricky goto's produced better codes are long gone.

This patch should express the same in a better way.

(Also fixes the final gcc-4.0 x86 compile error)

Signed-off-by: Adrian Bunk <bunk@stusta.de>
Cc: Jeff Garzik <jgarzik@pobox.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-02 15:12:31 -07:00
Al Viro
a553260618 [PATCH] ISA DMA Kconfig fixes - part 3
Drivers that expect ISA DMA API are marked as such in Kconfig.

Signed-off-by: Al Viro <viro@parcelfarce.linux.theplanet.co.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-05-04 07:33:14 -07:00
Arnaldo Carvalho de Melo
56cb515628 [AX25] Introduce ax25_type_trans
Replacing the open coded equivalents and making ax25 look more like
a linux network protocol, i.e. more similar to inet.

Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-04-24 18:53:06 -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