Commit Graph

23 Commits

Author SHA1 Message Date
Geoff Levand c18e68696f net/connector: Add const qualifier to cb_id
The connector driver never modifies any cb_id passed to it, so add a const
qualifier to those arguments so callers can declare their struct cb_id as a
constant object.

Fixes build warnings like these when passing a constant struct cb_id:

  warning: passing argument 1 of ‘cn_add_callback’ discards ‘const’ qualifier from pointer target

Signed-off-by: Geoff Levand <geoff@infradead.org>
Link: https://lore.kernel.org/r/a9e49c9e-67fa-16e7-0a6b-72f6bd30c58a@infradead.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2020-12-16 11:06:49 -08:00
Thomas Gleixner 1a59d1b8e0 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version this program is distributed in the
  hope that it will be useful but without any warranty without even
  the implied warranty of merchantability or fitness for a particular
  purpose see the gnu general public license for more details you
  should have received a copy of the gnu general public license along
  with this program if not write to the free software foundation inc
  59 temple place suite 330 boston ma 02111 1307 usa

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 1334 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30 11:26:35 -07:00
Elena Reshetova e65f7ee39b drivers, connector: convert cn_callback_entry.refcnt from atomic_t to refcount_t
atomic_t variables are currently used to implement reference
counters with the following properties:
 - counter is initialized to 1 using atomic_set()
 - a resource is freed upon counter reaching zero
 - once counter reaches zero, its further
   increments aren't allowed
 - counter schema uses basic atomic operations
   (set, inc, inc_not_zero, dec_and_test, etc.)

Such atomic variables should be converted to a newly provided
refcount_t type and API that prevents accidental counter overflows
and underflows. This is important since overflows and underflows
can lead to use-after-free situation and be exploitable.

The variable cn_callback_entry.refcnt is used as pure reference counter.
Convert it to refcount_t and fix up the operations.

Suggested-by: Kees Cook <keescook@chromium.org>
Reviewed-by: David Windsor <dwindsor@gmail.com>
Reviewed-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-22 02:22:39 +01:00
Valentin Ilie f3c48ecce5 drivers: connector: fixed coding style issues
V2: Replaced assignment in if statement.
Fixed coding style issues.

Signed-off-by: Valentin Ilie <valentin.ilie@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-07-16 23:23:52 -07:00
Patrick McHardy 04f482faf5 connector: convert to synchronous netlink message processing
Commits 01a16b21 (netlink: kill eff_cap from struct netlink_skb_parms)
and c53fa1ed (netlink: kill loginuid/sessionid/sid members from struct
netlink_skb_parms) removed some members from struct netlink_skb_parms
that depend on the current context, all netlink users are now required
to do synchronous message processing.

connector however queues received messages and processes them in a work
queue, which is not valid anymore. This patch converts connector to do
synchronous message processing by invoking the registered callback handler
directly from the netlink receive function.

In order to avoid invoking the callback with connector locks held, a
reference count is added to struct cn_callback_entry, the reference
is taken when finding a matching callback entry on the device's queue_list
and released after the callback handler has been invoked.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-03-30 17:14:33 -07:00
Joe Perches 008536e845 connector: Convert char *name to const char *name
Allow more const declarations.

Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-02-23 13:22:26 -08:00
Tejun Heo 6cebb17bee connector: remove lazy workqueue creation
Commit 1a5645bc (connector: create connector workqueue only while
needed once) implements lazy workqueue creation for connector
workqueue.  With cmwq now in place, lazy workqueue creation doesn't
make much sense while adding a lot of complexity.  Remove it and
allocate an ordered workqueue during initialization.

This also removes a call to flush_scheduled_work() which is deprecated
and scheduled to be removed.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-10-24 14:20:01 -07:00
Philipp Reisner f1489cfb17 connector: Removed the destruct_data callback since it is always kfree_skb()
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Acked-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-10-02 10:54:05 -07:00
Philipp Reisner 7069331dbe connector: Provide the sender's credentials to the callback
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Acked-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-10-02 10:54:01 -07:00
Philipp Reisner 293500a23f connector: Keep the skb in cn_callback_data
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Acked-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-10-02 10:53:58 -07:00
David S. Miller 74d154189d Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
Conflicts:
	drivers/net/wireless/iwmc3200wifi/netdev.c
	net/wireless/scan.c
2009-07-23 19:03:51 -07:00
Evgeniy Polyakov acb9c1b2f4 connector: maintainer/mail update.
Signed-off-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-07-21 12:43:51 -07:00
Mike Frysinger 0741241c6b connector: make callback argument type explicit
The connector documentation states that the argument to the callback
function is always a pointer to a struct cn_msg, but rather than encode it
in the API itself, it uses a void pointer everywhere.  This doesn't make
much sense to encode the pointer in documentation as it prevents proper C
type checking from occurring and can easily allow people to use the wrong
pointer type.  So convert the argument type to an explicit struct cn_msg
pointer.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-07-17 10:13:21 -07:00
Frederic Weisbecker 1a5645bc90 connector: create connector workqueue only while needed once
The netlink connector uses its own workqueue to relay the datas sent
from userspace to the appropriate callback.  If you launch the test
from Documentation/connector and change it a bit to send a high flow
of data, you will see thousands of events coming to the "cqueue"
workqueue by looking at the workqueue tracer.

This flow of events can be sent very quickly. So, to not encumber the
kevent workqueue and delay other jobs, the "cqueue" workqueue should
remain.

But this workqueue is pointless most of the time, it will always be
created (assuming you have built it of course) although only
developpers with specific needs will use it.

So avoid this "most of the time useless task", this patch proposes to
create this workqueue only when needed once.  The first jobs to be
sent to connector callbacks will be sent to kevent while the "cqueue"
thread creation will be scheduled to kevent too.

The following jobs will continue to be scheduled to keventd until the
cqueue workqueue is created, and then the rest of the jobs will
continue to perform as usual, through this dedicated workqueue.

Each time I tested this patch, only the first event was sent to
keventd, the rest has been sent to cqueue which have been created
quickly.

Also, this patch fixes some trailing whitespaces on the connector files.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-02-02 23:22:04 -08:00
Evgeniy Polyakov 4b1b366721 connector: convert to single-threaded workqueue
From: Evgeniy Polyakov <johnpol@2ka.mipt.ru>

We don't need one cqueue thread for each CPU.  cqueue is used for
receiving userspace datagrams, which are very rare and thus will
happily live with a single queue.

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-03-23 21:51:12 -07:00
Li Zefan 6e32814bc8 [CONNECTOR]: Cleanup struct cn_callback_entry
- 'cb' is a fake struct member. In a previous patch struct cn_callback
was renamed to cn_callback_id, so 'cb' should have been deleted at that
time.

- 'nls' isn't used and is redundant, we can retrieve this data through
cn_callback_entry.pdev->nls.

- 'seq' and 'group' should be u32, as they are declared to be u32 in
other places.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-01-28 15:00:40 -08:00
Li Zefan 96a899655e [CONNECTOR]: Cleanup struct cn_queue_dev
Struct member netlink_groups is never used, and I don't see how it can
be useful.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-01-28 15:00:39 -08:00
Li Zefan cf585ae8ae [CONNECTOR]: Don't touch queue dev after decrement of ref count.
cn_queue_free_callback() will touch 'dev'(i.e. cbq->pdev), so it
should be called before atomic_dec(&dev->refcnt).

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-01-08 23:44:44 -08:00
Evgeniy Polyakov a240d9f1d8 [CONNECTOR]: Replace delayed work with usual work queue.
Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-12-18 01:53:58 -08:00
David Howells c4028958b6 WorkStruct: make allyesconfig
Fix up for make allyesconfig.

Signed-Off-By: David Howells <dhowells@redhat.com>
2006-11-22 14:57:56 +00:00
Andreas Schwab cec6f7f39c [CONNECTOR]: Fix warning in cn_queue.c
cn_queue.c:130: warning: value computed is not used

There is no point in testing the atomic value if the result is thrown
away.

From Evgeniy:

It was created to put implicit smp barrier, but it is not needed there.

Signed-off-by: Andreas Schwab <schwab@suse.de>
Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-17 21:29:43 -07:00
Evgeniy Polyakov acd042bb2d [CONNECTOR]: async connector mode.
If input message rate from userspace is too high, do not drop them,
but try to deliver using work queue allocation.

Failing there is some kind of congestion control.

It also removes warn_on on this condition, which scares people.

Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-09-26 15:06:50 -07:00
Evgeniy Polyakov 7672d0b544 [NET]: Add netlink connector.
Kernel connector - new userspace <-> kernel space easy to use
communication module which implements easy to use bidirectional
message bus using netlink as it's backend.  Connector was created to
eliminate complex skb handling both in send and receive message bus
direction.

Connector driver adds possibility to connect various agents using as
one of it's backends netlink based network.  One must register
callback and identifier. When driver receives special netlink message
with appropriate identifier, appropriate callback will be called.

From the userspace point of view it's quite straightforward:

	socket();
	bind();
	send();
	recv();

But if kernelspace want to use full power of such connections, driver
writer must create special sockets, must know about struct sk_buff
handling...  Connector allows any kernelspace agents to use netlink
based networking for inter-process communication in a significantly
easier way:

int cn_add_callback(struct cb_id *id, char *name, void (*callback) (void *));
void cn_netlink_send(struct cn_msg *msg, u32 __groups, int gfp_mask);

struct cb_id
{
	__u32			idx;
	__u32			val;
};

idx and val are unique identifiers which must be registered in
connector.h for in-kernel usage.  void (*callback) (void *) - is a
callback function which will be called when message with above idx.val
will be received by connector core.

Using connector completely hides low-level transport layer from it's
users.

Connector uses new netlink ability to have many groups in one socket.

[ Incorporating many cleanups and fixes by myself and
  Andrew Morton -DaveM ]

Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-09-11 19:15:07 -07:00