Commit Graph

92 Commits

Author SHA1 Message Date
Randy Dunlap e63340ae6b header cleaning: don't include smp_lock.h when not used
Remove includes of <linux/smp_lock.h> where it is not used/needed.
Suggested by Al Viro.

Builds cleanly on x86_64, i386, alpha, ia64, powerpc, sparc,
sparc64, and arm (all 59 defconfigs).

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-08 11:15:07 -07:00
Patrick McHardy 9e71efcd6d [NETLINK]: Remove bogus BUG_ON
Remove bogus BUG_ON(mutex_is_locked(nlk_sk(sk)->cb_mutex)), when the
netlink_kernel_create caller specifies an external mutex it might
validly be locked.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-05-04 12:15:11 -07:00
Patrick McHardy 188ccb5583 [NETLINK]: Fix use after free in netlink_recvmsg
When the user passes in MSG_TRUNC the skb is used after getting freed.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-05-03 03:27:01 -07:00
Herbert Xu 3f660d66df [NETLINK]: Kill CB only when socket is unused
Since we can still receive packets until all references to the
socket are gone, we don't need to kill the CB until that happens.
This also aligns ourselves with the receive queue purging which
happens at that point.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-05-03 03:17:14 -07:00
Adrian Bunk 42bad1da50 [NETLINK]: Possible cleanups.
- make the following needlessly global variables static:
  - core/rtnetlink.c: struct rtnl_msg_handlers[]
  - netfilter/nf_conntrack_proto.c: struct nf_ct_protos[]
- make the following needlessly global functions static:
  - core/rtnetlink.c: rtnl_dump_all()
  - netlink/af_netlink.c: netlink_queue_skip()

Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-26 00:57:41 -07:00
Patrick McHardy ffa4d7216e [NETLINK]: don't reinitialize callback mutex
Don't reinitialize the callback mutex the netlink_kernel_create caller
handed in, it is supposed to already be initialized and could already
be held by someone.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25 22:29:06 -07:00
Patrick McHardy af65bdfce9 [NETLINK]: Switch cb_lock spinlock to mutex and allow to override it
Switch cb_lock to mutex and allow netlink kernel users to override it
with a subsystem specific mutex for consistent locking in dump callbacks.
All netlink_dump_start users have been audited not to rely on any
side-effects of the previously used spinlock.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25 22:29:03 -07:00
Johannes Berg d30045a0bc [NETLINK]: introduce NLA_BINARY type
This patch introduces a new NLA_BINARY attribute policy type with the
verification of simply checking the maximum length of the payload.

It also fixes a small typo in the example.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25 22:28:05 -07:00
Thomas Graf c702e8047f [NETLINK]: Directly return -EINTR from netlink_dump_start()
Now that all users of netlink_dump_start() use netlink_run_queue()
to process the receive queue, it is possible to return -EINTR from
netlink_dump_start() directly, therefore simplying the callers.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25 22:27:33 -07:00
Thomas Graf 1d00a4eb42 [NETLINK]: Remove error pointer from netlink message handler
The error pointer argument in netlink message handlers is used
to signal the special case where processing has to be interrupted
because a dump was started but no error happened. Instead it is
simpler and more clear to return -EINTR and have netlink_run_queue()
deal with getting the queue right.

nfnetlink passed on this error pointer to its subsystem handlers
but only uses it to signal the start of a netlink dump. Therefore
it can be removed there as well.

This patch also cleans up the error handling in the affected
message handlers to be consistent since it had to be touched anyway.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25 22:27:30 -07:00
Thomas Graf 45e7ae7f71 [NETLINK]: Ignore control messages directly in netlink_run_queue()
Changes netlink_rcv_skb() to skip netlink controll messages and don't
pass them on to the message handler.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25 22:27:29 -07:00
Thomas Graf d35b685640 [NETLINK]: Ignore !NLM_F_REQUEST messages directly in netlink_run_queue()
netlink_rcv_skb() is changed to skip messages which don't have the
NLM_F_REQUEST bit to avoid every netlink family having to perform this
check on their own.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25 22:27:29 -07:00
Thomas Graf 33a0543cd9 [NETLINK]: Remove unused groups variable
Leftover from dynamic multicast groups allocation work.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25 22:27:27 -07:00
Arnaldo Carvalho de Melo b529ccf279 [NETLINK]: Introduce nlmsg_hdr() helper
For the common "(struct nlmsghdr *)skb->data" sequence, so that we reduce the
number of direct accesses to skb->data and for consistency with all the other
cast skb member helpers.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25 22:26:34 -07:00
Arnaldo Carvalho de Melo 4305b54135 [SK_BUFF]: Convert skb->end to sk_buff_data_t
Now to convert the last one, skb->data, that will allow many simplifications
and removal of some of the offset helpers.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25 22:26:29 -07:00
Arnaldo Carvalho de Melo 27a884dc3c [SK_BUFF]: Convert skb->tail to sk_buff_data_t
So that it is also an offset from skb->head, reduces its size from 8 to 4 bytes
on 64bit architectures, allowing us to combine the 4 bytes hole left by the
layer headers conversion, reducing struct sk_buff size to 256 bytes, i.e. 4
64byte cachelines, and since the sk_buff slab cache is SLAB_HWCACHE_ALIGN...
:-)

Many calculations that previously required that skb->{transport,network,
mac}_header be first converted to a pointer now can be done directly, being
meaningful as offsets or pointers.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25 22:26:28 -07:00
Arnaldo Carvalho de Melo badff6d01a [SK_BUFF]: Introduce skb_reset_transport_header(skb)
For the common, open coded 'skb->h.raw = skb->data' operation, so that we can
later turn skb->h.raw into a offset, reducing the size of struct sk_buff in
64bit land while possibly keeping it as a pointer on 32bit.

This one touches just the most simple cases:

skb->h.raw = skb->data;
skb->h.raw = {skb_push|[__]skb_pull}()

The next ones will handle the slightly more "complex" cases.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25 22:25:15 -07:00
Adrian Bunk cb69cc5236 [TCP/DCCP/RANDOM]: Remove unused exports.
This patch removes the following not or no longer used exports:
- drivers/char/random.c: secure_tcp_sequence_number
- net/dccp/options.c: sysctl_dccp_feat_sequence_window
- net/netlink/af_netlink.c: netlink_set_err

Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25 22:24:03 -07:00
David S. Miller b558ff7999 [NETLINK]: Mirror UDP MSG_TRUNC semantics.
If the user passes MSG_TRUNC in via msg_flags, return
the full packet size not the truncated size.

Idea from Herbert Xu and Thomas Graf.

Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25 22:23:35 -07:00
Denis Lunev ac57b3a9ce [NETLINK]: Don't attach callback to a going-away netlink socket
There is a race between netlink_dump_start() and netlink_release()
that can lead to the situation when a netlink socket with non-zero
callback is freed.

Here it is:

CPU1:                           CPU2
netlink_release():              netlink_dump_start():

                                sk = netlink_lookup(); /* OK */

netlink_remove();

spin_lock(&nlk->cb_lock);
if (nlk->cb) { /* false */
  ...
}
spin_unlock(&nlk->cb_lock);

                                spin_lock(&nlk->cb_lock);
                                if (nlk->cb) { /* false */
                                         ...
                                }
                                nlk->cb = cb;
                                spin_unlock(&nlk->cb_lock);
                                ...
sock_orphan(sk);
/*
 * proceed with releasing
 * the socket
 */

The proposal it to make sock_orphan before detaching the callback
in netlink_release() and to check for the sock to be SOCK_DEAD in
netlink_dump_start() before setting a new callback.

Signed-off-by: Denis Lunev <den@openvz.org>
Signed-off-by: Kirill Korotaev <dev@openvz.org>
Signed-off-by: Pavel Emelianov <xemul@openvz.org>
Acked-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-18 17:05:58 -07:00
Arjan van de Ven da7071d7e3 [PATCH] mark struct file_operations const 8
Many struct file_operations in the kernel can be "const".  Marking them const
moves these to the .rodata section, which avoids false sharing with potential
dirty data.  In addition it'll catch accidental writes at compile time to
these shared resources.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 09:48:46 -08:00
YOSHIFUJI Hideaki 746fac4dcd [NET] NETLINK: Fix whitespace errors.
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-02-10 23:19:58 -08:00
Mariusz Kozlowski 5e7c001c62 [AF_NETLINK]: module_put cleanup
This patch removes redundant argument check for module_put().

Signed-off-by: Mariusz Kozlowski <m.kozlowski@tuxland.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-01-03 18:38:15 -08:00
Josef Sipek 6db5fc5d53 [PATCH] struct path: convert netlink
Signed-off-by: Josef Sipek <jsipek@fsl.cs.sunysb.edu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-08 08:28:48 -08:00
Jamal Hadi Salim 48d4ed7a86 [GENETLINK]: Fix misplaced command flags.
The command flags for dump and do were swapped..

Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-12-06 20:06:25 -08:00
Jamal Hadi Salim 334c29a645 [GENETLINK]: Move command capabilities to flags.
This patch moves command capabilities to command flags. Other than
being cleaner, saves several bytes.
We increment the nlctrl version so as to signal to user space that
to not expect the attributes. We will try to be careful
not to do this too often ;->

Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-12-06 18:38:41 -08:00
Jamal Hadi Salim a4d1366d50 [GENETLINK]: Add cmd dump completion.
Remove assumption that generic netlink commands cannot have dump
completion callbacks.

Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-12-02 21:32:09 -08:00
Thomas Graf 4e9b826935 [NETLINK]: Remove unused dst_pid field in netlink_skb_parms
The destination PID is passed directly to netlink_unicast()
respectively netlink_multicast().

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-12-02 21:30:43 -08:00
Thomas Graf e94ef68205 [GENETLINK] ctrl: Avoid empty CTRL_ATTR_OPS attribute when dumping
Based on Jamal's patch but compiled and even tested. :-)

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-12-02 21:30:23 -08:00
Thomas Graf 17c157c889 [GENL]: Add genlmsg_put_reply() to simplify building reply headers
By modyfing genlmsg_put() to take a genl_family and by adding
genlmsg_put_reply() the process of constructing the netlink
and generic netlink headers is simplified.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Acked-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-12-02 21:22:42 -08:00
Thomas Graf 81878d27fd [GENL]: Add genlmsg_reply() to simply unicast replies to requests
A generic netlink user has no interest in knowing how to
address the source of the original request.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Acked-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-12-02 21:22:41 -08:00
Thomas Graf 339bf98ffc [NETLINK]: Do precise netlink message allocations where possible
Account for the netlink message header size directly in nlmsg_new()
instead of relying on the caller calculate it correctly.

Replaces error handling of message construction functions when
constructing notifications with bug traps since a failure implies
a bug in calculating the size of the skb.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Acked-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-12-02 21:22:11 -08:00
Heiko Carstens a27b58fed9 [NET]: fix uaccess handling
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-10-30 15:24:41 -08:00
Thomas Graf eb328111ef [GENL]: Provide more information to userspace about registered genl families
Additionaly exports the following information when providing
the list of registered generic netlink families:
  - protocol version
  - header size
  - maximum number of attributes
  - list of available operations including
      - id
      - flags
      - avaiability of policy and doit/dumpit function

libnl HEAD provides a utility to read this new information:

	0x0010 nlctrl version 1
	    hdrsize 0 maxattr 6
	      op GETFAMILY (0x03) [POLICY,DOIT,DUMPIT]
	0x0011 NLBL_MGMT version 1
	    hdrsize 0 maxattr 0
	      op unknown (0x02) [DOIT]
	      op unknown (0x03) [DOIT]
	      ....

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-09-22 15:18:51 -07:00
Thomas Graf 5176f91ea8 [NETLINK]: Make use of NLA_STRING/NLA_NUL_STRING attribute validation
Converts existing NLA_STRING attributes to use the new
validation features, saving a couple of temporary buffers.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-09-22 15:18:25 -07:00
Thomas Graf a5531a5d85 [NETLINK]: Improve string attribute validation
Introduces a new attribute type NLA_NUL_STRING to support NUL
terminated strings. Attributes of this kind require to carry
a terminating NUL within the maximum specified in the policy.

The `old' NLA_STRING which is not required to be NUL terminated
is extended to provide means to specify a maximum length of the
string.

Aims at easing the pain with using nla_strlcpy() on temporary
buffers.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-09-22 15:18:24 -07:00
YOSHIFUJI Hideaki ef047f5e10 [NET]: Use BUILD_BUG_ON() for checking size of skb->cb.
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-09-22 15:18:15 -07:00
Thomas Graf d387f6ad10 [NETLINK]: Add notification message sending interface
Adds nlmsg_notify() implementing proper notification logic. The
message is multicasted to all listeners in the group. The
applications the requests orignates from can request a unicast
back report in which case said socket will be excluded from the
multicast to avoid duplicated notifications.

nlmsg_multicast() is extended to take allocation flags to
allow notification in atomic contexts.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-09-22 14:54:49 -07:00
Thomas Graf bf8b79e444 [NETLINK]: Convert core netlink handling to new netlink api
Fixes a theoretical memory and locking leak when the size of
the netlink header would exceed the skb tailroom.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-09-22 14:53:44 -07:00
Thomas Graf fe4944e59c [NETLINK]: Extend netlink messaging interface
Adds:
 nlmsg_get_pos()                 return current position in message
 nlmsg_trim()                    trim part of message
 nla_reserve_nohdr(skb, len)     reserve room for an attribute w/o hdr
 nla_put_nohdr(skb, len, data)   add attribute w/o hdr
 nla_find_nested()               find attribute in nested attributes

Fixes nlmsg_new() to take allocation flags and consider size.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-09-22 14:53:43 -07:00
Akinobu Mita fab2caf62e [NETLINK]: Call panic if nl_table allocation fails
This patch makes crash happen if initialization of nl_table fails
in initcalls. It is better than getting use after free crash later.

Signed-off-by: Akinobu Mita <mita@miraclelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-29 21:22:18 -07:00
Panagiotis Issaris 0da974f4f3 [NET]: Conversions from kmalloc+memset to k(z|c)alloc.
Signed-off-by: Panagiotis Issaris <takis@issaris.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-07-21 14:51:30 -07:00
Arjan van de Ven 6abd219c6e [PATCH] bcm43xx: netlink deadlock fix
reported by Jure Repinc:

> > http://bugzilla.kernel.org/show_bug.cgi?id=6773

> > checked out dmesg output and found the message
> >
> > ======================================================
> > [ BUG: hard-safe -> hard-unsafe lock order detected! ]
> > ------------------------------------------------------
> >
> > starting at line 660 of the dmesg.txt that I will attach.

The patch below should fix the deadlock, albeit I suspect it's not the
"right" fix; the right fix may well be to move the rx processing in bcm43xx
to softirq context.  [it's debatable, ipw2200 hit this exact same bug; at
some point it's better to bite the bullet and move this to the common layer
as my patch below does]

Make the nl_table_lock irq-safe; it's taken for read in various netlink
functions, including functions that several wireless drivers (ipw2200,
bcm43xx) want to call from hardirq context.

The deadlock was found by the lock validator.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Michael Buesch <mb@bu3sch.de>
Cc: "John W. Linville" <linville@tuxdriver.com>
Cc: Jeff Garzik <jeff@garzik.org>
Acked-by: "David S. Miller" <davem@davemloft.net>
Cc: jamal <hadi@cyberus.ca>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-03 15:26:58 -07:00
Jörn Engel 6ab3d5624e Remove obsolete #include <linux/config.h>
Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
2006-06-30 19:25:36 +02:00
Darrel Goeddel c7bdb545d2 [NETLINK]: Encapsulate eff_cap usage within security framework.
This patch encapsulates the usage of eff_cap (in netlink_skb_params) within
the security framework by extending security_netlink_recv to include a required
capability parameter and converting all direct usage of eff_caps outside
of the lsm modules to use the interface.  It also updates the SELinux
implementation of the security_netlink_send and security_netlink_recv
hooks to take advantage of the sid in the netlink_skb_params struct.
This also enables SELinux to perform auditing of netlink capability checks.
Please apply, for 2.6.18 if possible.

Signed-off-by: Darrel Goeddel <dgoeddel@trustedcs.com>
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by:  James Morris <jmorris@namei.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-29 16:57:55 -07:00
Linus Torvalds 532f57da40 Merge branch 'audit.b10' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit-current
* 'audit.b10' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit-current:
  [PATCH] Audit Filter Performance
  [PATCH] Rework of IPC auditing
  [PATCH] More user space subject labels
  [PATCH] Reworked patch for labels on user space messages
  [PATCH] change lspp ipc auditing
  [PATCH] audit inode patch
  [PATCH] support for context based audit filtering, part 2
  [PATCH] support for context based audit filtering
  [PATCH] no need to wank with task_lock() and pinning task down in audit_syscall_exit()
  [PATCH] drop task argument of audit_syscall_{entry,exit}
  [PATCH] drop gfp_mask in audit_log_exit()
  [PATCH] move call of audit_free() into do_exit()
  [PATCH] sockaddr patch
  [PATCH] deal with deadlocks in audit_free()
2006-05-01 21:43:05 -07:00
Steve Grubb e7c3497013 [PATCH] Reworked patch for labels on user space messages
The below patch should be applied after the inode and ipc sid patches.
This patch is a reworking of Tim's patch that has been updated to match
the inode and ipc patches since its similar.

[updated:
>  Stephen Smalley also wanted to change a variable from isec to tsec in the
>  user sid patch.                                                              ]

Signed-off-by: Steve Grubb <sgrubb@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-05-01 06:09:58 -04:00
Soyoung Park 09493abfdb [NETLINK]: cleanup unused macro in net/netlink/af_netlink.c
1 line removal, of unused macro.
ran 'egrep -r' from linux-2.6.16/ for Nprintk and
didn't see it anywhere else but here, in #define...

Signed-off-by: Soyoung Park <speattle@yahoo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-04-29 18:33:13 -07:00
Alan Stern e041c68341 [PATCH] Notifier chain update: API changes
The kernel's implementation of notifier chains is unsafe.  There is no
protection against entries being added to or removed from a chain while the
chain is in use.  The issues were discussed in this thread:

    http://marc.theaimsgroup.com/?l=linux-kernel&m=113018709002036&w=2

We noticed that notifier chains in the kernel fall into two basic usage
classes:

	"Blocking" chains are always called from a process context
	and the callout routines are allowed to sleep;

	"Atomic" chains can be called from an atomic context and
	the callout routines are not allowed to sleep.

We decided to codify this distinction and make it part of the API.  Therefore
this set of patches introduces three new, parallel APIs: one for blocking
notifiers, one for atomic notifiers, and one for "raw" notifiers (which is
really just the old API under a new name).  New kinds of data structures are
used for the heads of the chains, and new routines are defined for
registration, unregistration, and calling a chain.  The three APIs are
explained in include/linux/notifier.h and their implementation is in
kernel/sys.c.

With atomic and blocking chains, the implementation guarantees that the chain
links will not be corrupted and that chain callers will not get messed up by
entries being added or removed.  For raw chains the implementation provides no
guarantees at all; users of this API must provide their own protections.  (The
idea was that situations may come up where the assumptions of the atomic and
blocking APIs are not appropriate, so it should be possible for users to
handle these things in their own way.)

There are some limitations, which should not be too hard to live with.  For
atomic/blocking chains, registration and unregistration must always be done in
a process context since the chain is protected by a mutex/rwsem.  Also, a
callout routine for a non-raw chain must not try to register or unregister
entries on its own chain.  (This did happen in a couple of places and the code
had to be changed to avoid it.)

Since atomic chains may be called from within an NMI handler, they cannot use
spinlocks for synchronization.  Instead we use RCU.  The overhead falls almost
entirely in the unregister routine, which is okay since unregistration is much
less frequent that calling a chain.

Here is the list of chains that we adjusted and their classifications.  None
of them use the raw API, so for the moment it is only a placeholder.

  ATOMIC CHAINS
  -------------
arch/i386/kernel/traps.c:		i386die_chain
arch/ia64/kernel/traps.c:		ia64die_chain
arch/powerpc/kernel/traps.c:		powerpc_die_chain
arch/sparc64/kernel/traps.c:		sparc64die_chain
arch/x86_64/kernel/traps.c:		die_chain
drivers/char/ipmi/ipmi_si_intf.c:	xaction_notifier_list
kernel/panic.c:				panic_notifier_list
kernel/profile.c:			task_free_notifier
net/bluetooth/hci_core.c:		hci_notifier
net/ipv4/netfilter/ip_conntrack_core.c:	ip_conntrack_chain
net/ipv4/netfilter/ip_conntrack_core.c:	ip_conntrack_expect_chain
net/ipv6/addrconf.c:			inet6addr_chain
net/netfilter/nf_conntrack_core.c:	nf_conntrack_chain
net/netfilter/nf_conntrack_core.c:	nf_conntrack_expect_chain
net/netlink/af_netlink.c:		netlink_chain

  BLOCKING CHAINS
  ---------------
arch/powerpc/platforms/pseries/reconfig.c:	pSeries_reconfig_chain
arch/s390/kernel/process.c:		idle_chain
arch/x86_64/kernel/process.c		idle_notifier
drivers/base/memory.c:			memory_chain
drivers/cpufreq/cpufreq.c		cpufreq_policy_notifier_list
drivers/cpufreq/cpufreq.c		cpufreq_transition_notifier_list
drivers/macintosh/adb.c:		adb_client_list
drivers/macintosh/via-pmu.c		sleep_notifier_list
drivers/macintosh/via-pmu68k.c		sleep_notifier_list
drivers/macintosh/windfarm_core.c	wf_client_list
drivers/usb/core/notify.c		usb_notifier_list
drivers/video/fbmem.c			fb_notifier_list
kernel/cpu.c				cpu_chain
kernel/module.c				module_notify_list
kernel/profile.c			munmap_notifier
kernel/profile.c			task_exit_notifier
kernel/sys.c				reboot_notifier_list
net/core/dev.c				netdev_chain
net/decnet/dn_dev.c:			dnaddr_chain
net/ipv4/devinet.c:			inetaddr_chain

It's possible that some of these classifications are wrong.  If they are,
please let us know or submit a patch to fix them.  Note that any chain that
gets called very frequently should be atomic, because the rwsem read-locking
used for blocking chains is very likely to incur cache misses on SMP systems.
(However, if the chain's callout routines may sleep then the chain cannot be
atomic.)

The patch set was written by Alan Stern and Chandra Seetharaman, incorporating
material written by Keith Owens and suggestions from Paul McKenney and Andrew
Morton.

[jes@sgi.com: restructure the notifier chain initialization macros]
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Jes Sorensen <jes@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-27 08:44:50 -08:00
Ingo Molnar 14cc3e2b63 [PATCH] sem2mutex: misc static one-file mutexes
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: Dave Jones <davej@codemonkey.org.uk>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Jens Axboe <axboe@suse.de>
Cc: Neil Brown <neilb@cse.unsw.edu.au>
Acked-by: Alasdair G Kergon <agk@redhat.com>
Cc: Greg KH <greg@kroah.com>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Adam Belay <ambx1@neo.rr.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-26 08:56:55 -08:00