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* [NETLINK]: Mark netlink policies constPatrick McHardy2007-06-072-5/+5
| | | | | Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* header cleaning: don't include smp_lock.h when not usedRandy Dunlap2007-05-081-1/+0
| | | | | | | | | | | | 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>
* [NETLINK]: Remove bogus BUG_ONPatrick McHardy2007-05-041-1/+0
| | | | | | | | | 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>
* [NETLINK]: Fix use after free in netlink_recvmsgPatrick McHardy2007-05-031-4/+2
| | | | | | | | 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>
* [NETLINK]: Kill CB only when socket is unusedHerbert Xu2007-05-031-14/+15
| | | | | | | | | | 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>
* [NETLINK]: Possible cleanups.Adrian Bunk2007-04-261-2/+2
| | | | | | | | | | | | | - 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>
* [NETLINK]: don't reinitialize callback mutexPatrick McHardy2007-04-261-2/+6
| | | | | | | | | 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>
* [NETLINK]: Switch cb_lock spinlock to mutex and allow to override itPatrick McHardy2007-04-262-16/+24
| | | | | | | | | | 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>
* [NETLINK]: introduce NLA_BINARY typeJohannes Berg2007-04-261-0/+5
| | | | | | | | | | | 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>
* [NETLINK]: Directly return -EINTR from netlink_dump_start()Thomas Graf2007-04-262-6/+8
| | | | | | | | | 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>
* [NETLINK]: Remove error pointer from netlink message handlerThomas Graf2007-04-262-45/+32
| | | | | | | | | | | | | | | | | | 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>
* [NETLINK]: Ignore control messages directly in netlink_run_queue()Thomas Graf2007-04-262-6/+4
| | | | | | | | 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>
* [NETLINK]: Ignore !NLM_F_REQUEST messages directly in netlink_run_queue()Thomas Graf2007-04-262-5/+8
| | | | | | | | | 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>
* [NETLINK]: Remove unused groups variableThomas Graf2007-04-261-2/+0
| | | | | | | Leftover from dynamic multicast groups allocation work. Signed-off-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NETLINK]: Introduce nlmsg_hdr() helperArnaldo Carvalho de Melo2007-04-261-1/+1
| | | | | | | | | 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>
* [SK_BUFF]: Convert skb->end to sk_buff_data_tArnaldo Carvalho de Melo2007-04-261-1/+1
| | | | | | | | 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>
* [SK_BUFF]: Convert skb->tail to sk_buff_data_tArnaldo Carvalho de Melo2007-04-261-1/+1
| | | | | | | | | | | | | | | 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>
* [SK_BUFF]: Introduce skb_reset_transport_header(skb)Arnaldo Carvalho de Melo2007-04-261-1/+1
| | | | | | | | | | | | | | | | 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>
* [TCP/DCCP/RANDOM]: Remove unused exports.Adrian Bunk2007-04-261-1/+0
| | | | | | | | | | 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>
* [NETLINK]: Mirror UDP MSG_TRUNC semantics.David S. Miller2007-04-261-0/+3
| | | | | | | | | 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>
* [NETLINK]: Don't attach callback to a going-away netlink socketDenis Lunev2007-04-191-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* [PATCH] mark struct file_operations const 8Arjan van de Ven2007-02-121-1/+1
| | | | | | | | | | | 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>
* [NET] NETLINK: Fix whitespace errors.YOSHIFUJI Hideaki2007-02-112-23/+23
| | | | | Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* [AF_NETLINK]: module_put cleanupMariusz Kozlowski2007-01-041-2/+1
| | | | | | | 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>
* [PATCH] struct path: convert netlinkJosef Sipek2006-12-081-1/+1
| | | | | | 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>
* [GENETLINK]: Fix misplaced command flags.Jamal Hadi Salim2006-12-071-2/+2
| | | | | | | 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>
* [GENETLINK]: Move command capabilities to flags.Jamal Hadi Salim2006-12-071-10/+8
| | | | | | | | | | | 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>
* [GENETLINK]: Add cmd dump completion.Jamal Hadi Salim2006-12-031-1/+1
| | | | | | | | 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>
* [NETLINK]: Remove unused dst_pid field in netlink_skb_parmsThomas Graf2006-12-031-1/+0
| | | | | | | | 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>
* [GENETLINK] ctrl: Avoid empty CTRL_ATTR_OPS attribute when dumpingThomas Graf2006-12-031-22/+25
| | | | | | | 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>
* [GENL]: Add genlmsg_put_reply() to simplify building reply headersThomas Graf2006-12-031-9/+8
| | | | | | | | | | 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>
* [GENL]: Add genlmsg_reply() to simply unicast replies to requestsThomas Graf2006-12-031-1/+1
| | | | | | | | | 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>
* [NETLINK]: Do precise netlink message allocations where possibleThomas Graf2006-12-032-8/+7
| | | | | | | | | | | | | 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>
* [NET]: fix uaccess handlingHeiko Carstens2006-10-311-2/+3
| | | | | Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* [GENL]: Provide more information to userspace about registered genl familiesThomas Graf2006-09-231-0/+40
| | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* [NETLINK]: Make use of NLA_STRING/NLA_NUL_STRING attribute validationThomas Graf2006-09-231-6/+4
| | | | | | | | 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>
* [NETLINK]: Improve string attribute validationThomas Graf2006-09-231-10/+39
| | | | | | | | | | | | | | | | 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>
* [NET]: Use BUILD_BUG_ON() for checking size of skb->cb.YOSHIFUJI Hideaki2006-09-231-4/+1
| | | | | Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NETLINK]: Add notification message sending interfaceThomas Graf2006-09-222-2/+34
| | | | | | | | | | | | | | 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>
* [NETLINK]: Convert core netlink handling to new netlink apiThomas Graf2006-09-221-19/+22
| | | | | | | | 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>
* [NETLINK]: Extend netlink messaging interfaceThomas Graf2006-09-222-1/+76
| | | | | | | | | | | | | | 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>
* [NETLINK]: Call panic if nl_table allocation failsAkinobu Mita2006-08-301-8/+6
| | | | | | | | 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>
* [NET]: Conversions from kmalloc+memset to k(z|c)alloc.Panagiotis Issaris2006-07-211-9/+4
| | | | | | Signed-off-by: Panagiotis Issaris <takis@issaris.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* [PATCH] bcm43xx: netlink deadlock fixArjan van de Ven2006-07-041-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* Remove obsolete #include <linux/config.h>Jörn Engel2006-06-303-3/+0
| | | | | Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de> Signed-off-by: Adrian Bunk <bunk@stusta.de>
* [NETLINK]: Encapsulate eff_cap usage within security framework.Darrel Goeddel2006-06-301-1/+1
| | | | | | | | | | | | | | | | 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>
* Merge branch 'audit.b10' of ↵Linus Torvalds2006-05-021-0/+2
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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()
| * [PATCH] Reworked patch for labels on user space messagesSteve Grubb2006-05-011-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | [NETLINK]: cleanup unused macro in net/netlink/af_netlink.cSoyoung Park2006-04-301-1/+0
|/ | | | | | | | | 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>
* [PATCH] Notifier chain update: API changesAlan Stern2006-03-271-4/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-30 02:49:20 +0100