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2006-03-27[PATCH] Notifier chain update: API changesAlan Stern1-1/+1
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>
2006-03-25[PATCH] roundup_pow_of_two() 64-bit fixAndrew Morton1-2/+3
fls() takes an integer, so roundup_pow_of_two() is busted for ulongs larger than 2^32-1. Fix this by implementing and using fls_long(). (Why does roundup_pow_of_two() return a long?) (Why is roundup_pow_of_two() __attribute_const__ whereas long_log2() is __attribute_pure__?) (Why does long_log2() suck so much? Because we were missing fls_long()?) Cc: Roland Dreier <rdreier@cisco.com> Cc: "Chen, Kenneth W" <kenneth.w.chen@intel.com> Cc: John Hawkes <hawkes@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-23[PATCH] pause_on_oops command line optionAndrew Morton1-0/+3
Attempt to fix the problem wherein people's oops reports scroll off the screen due to repeated oopsing or to oopses on other CPUs. If this happens the user can reboot with the `pause_on_oops=<seconds>' option. It will allow the first oopsing CPU to print an oops record just a single time. Second oopsing attempts, or oopses on other CPUs will cause those CPUs to enter a tight loop until the specified number of seconds have elapsed. The patch implements the infrastructure generically in the expectation that architectures other than x86 will find it useful. Cc: Dave Jones <davej@codemonkey.org.uk> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-17[PATCH] x86_64: Add boot option to disable randomized mappings and cleanupAndi Kleen1-6/+0
AMD SimNow!'s JIT doesn't like them at all in the guest. For distribution installation it's easiest if it's a boot time option. Also I moved the variable to a more appropiate place and make it independent from sysctl And marked __read_mostly which it is. Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-24[ACPI] merge 3549 4320 4485 4588 4980 5483 5651 acpica asus fops pnpacpi ↵Len Brown1-0/+1
branches into release Signed-off-by: Len Brown <len.brown@intel.com>
2006-01-17[IPV6]: Preserve procfs IPV6 address output formatYOSHIFUJI Hideaki1-0/+1
Procfs always output IPV6 addresses without the colon characters, and we cannot change that. Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-13[NET]: Use NIP6_FMT in kernel.hJoe Perches1-0/+2
There are errors and inconsistency in the display of NIP6 strings. ie: net/ipv6/ip6_flowlabel.c There are errors and inconsistency in the display of NIPQUAD strings too. ie: net/netfilter/nf_conntrack_ftp.c This patch: adds NIP6_FMT to kernel.h changes all code to use NIP6_FMT fixes net/ipv6/ip6_flowlabel.c adds NIPQUAD_FMT to kernel.h fixes net/netfilter/nf_conntrack_ftp.c changes a few uses of "%u.%u.%u.%u" to NIPQUAD_FMT for symmetry to NIP6_FMT Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-10[PATCH] dump_thread() cleanupakpm@osdl.org1-0/+4
) From: Adrian Bunk <bunk@stusta.de> - create one common dump_thread() prototype in kernel.h - dump_thread() is only used in fs/binfmt_aout.c and can therefore be removed on all architectures where CONFIG_BINFMT_AOUT is not available Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-09[PATCH] mutex subsystem, add typecheck_fn(type, function)Chuck Ebbert1-0/+9
add typecheck_fn(type, function) to do type-checking of function pointers. Modified-by: Ingo Molnar <mingo@elte.hu> (made it typeof() based, instead of typedef based.) Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2006-01-08[PATCH] remove gcc-2 checksAndrew Morton1-2/+0
Remove various things which were checking for gcc-1.x and gcc-2.x compilers. From: Adrian Bunk <bunk@stusta.de> Some documentation updates and removes some code paths for gcc < 3.2. Acked-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-12-15[ACPI] fix reboot upon suspend-to-diskAlexey Starikovskiy1-0/+1
http://bugzilla.kernel.org/show_bug.cgi?id=4320 Signed-off-by: Alexey Starikovskiy <alexey.y.starikovskiy@intel.com> Acked-by: Pavel Machek <pavel@suse.cz> Signed-off-by: Len Brown <len.brown@intel.com>
2005-11-07[PATCH] __deprecated_for_modules: panic_timeoutAdrian Bunk1-1/+1
This looks like something which out-of-tree code could possibly be using. Give panic_timeout the twelve-month treatment. Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-07[PATCH] kernel-docs: fix kernel-doc format problemsRandy Dunlap1-1/+0
Convert to proper kernel-doc format. Some have extra blank lines (not allowed immed. after the function name) or need blank lines (after all parameters). Function summary must be only one line. Colon (":") in a function description does weird things (causes kernel-doc to think that it's a new section head sadly). Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30[PATCH] include/linux/kernel.h:BUILD_BUG_ON(): fix a commentNikita Danilov1-1/+1
Fix comment describing BUILD_BUG_ON: BUG_ON is not an assertion (unfortunately). Signed-off-by: Nikita Danilov <nikita@clusterfs.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-13[PATCH] Make BUILD_BUG_ON fail at compile time.Andi Kleen1-2/+2
Force a compiler error instead of a link error, because they are easier to track down. Idea stolen from code by Jan Beulich <jbeulich@novell.com> If the argument to BUILD_BUG_ON evaluates to non-zero the compiler will do: t.c:6: error: size of array `type name' is negative (surprised that gcc doesn't have an extension for this) Signed-off-by: "Andi Kleen" <ak@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-25[PATCH] sched: voluntary kernel preemptionIngo Molnar1-5/+13
This patch adds a new preemption model: 'Voluntary Kernel Preemption'. The 3 models can be selected from a new menu: (X) No Forced Preemption (Server) ( ) Voluntary Kernel Preemption (Desktop) ( ) Preemptible Kernel (Low-Latency Desktop) we still default to the stock (Server) preemption model. Voluntary preemption works by adding a cond_resched() (reschedule-if-needed) call to every might_sleep() check. It is lighter than CONFIG_PREEMPT - at the cost of not having as tight latencies. It represents a different latency/complexity/overhead tradeoff. It has no runtime impact at all if disabled. Here are size stats that show how the various preemption models impact the kernel's size: text data bss dec hex filename 3618774 547184 179896 4345854 424ffe vmlinux.stock 3626406 547184 179896 4353486 426dce vmlinux.voluntary +0.2% 3748414 548640 179896 4476950 445016 vmlinux.preempt +3.5% voluntary-preempt is +0.2% of .text, preempt is +3.5%. This feature has been tested for many months by lots of people (and it's also included in the RHEL4 distribution and earlier variants were in Fedora as well), and it's intended for users and distributions who dont want to use full-blown CONFIG_PREEMPT for one reason or another. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-05-01[PATCH] clean up kernel messagesMatt Mackall1-0/+9
Arrange for all kernel printks to be no-ops. Only available if CONFIG_EMBEDDED. This patch saves about 375k on my laptop config and nearly 100k on minimal configs. Signed-off-by: Matt Mackall <mpm@selenic.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-04-16Linux-2.6.12-rc2v2.6.12-rc2Linus Torvalds1-0/+307
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!