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* Fix SMP poweroff hangsMark Lord2007-10-011-0/+2
| | | | | | | | | | | | | We need to disable all CPUs other than the boot CPU (usually 0) before attempting to power-off modern SMP machines. This fixes the hang-on-poweroff issue on my MythTV SMP box, and also on Thomas Gleixner's new toybox. Signed-off-by: Mark Lord <mlord@pobox.com> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* setpgid(child) fails if the child was forked by sub-threadOleg Nesterov2007-08-311-2/+1
| | | | | | | | | | | | | | | | | | | Spotted by Marcin Kowalczyk <qrczak@knm.org.pl>. sys_setpgid(child) fails if the child was forked by sub-thread. Fix the "is it our child" check. The previous commit ee0acf90d320c29916ba8c5c1b2e908d81f5057d was not complete. (this patch asks for the new same_thread_group() helper, but mainline doesn't have it yet). Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: Roland McGrath <roland@redhat.com> Cc: <stable@kernel.org> Tested-by: "Marcin 'Qrczak' Kowalczyk" <qrczak@knm.org.pl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Replace CONFIG_SOFTWARE_SUSPEND with CONFIG_HIBERNATIONRafael J. Wysocki2007-07-291-1/+1
| | | | | | | | | Replace CONFIG_SOFTWARE_SUSPEND with CONFIG_HIBERNATION to avoid confusion (among other things, with CONFIG_SUSPEND introduced in the next patch). Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Fix ThinkPad T42 poweroff failure introduced by by "PM: Introduce ↵Rafael J. Wysocki2007-07-261-0/+3
| | | | | | | | | | | | | | | | pm_power_off_prepare" Commit bd804eba1c8597cbb7cd5a5f9fe886aae16a079a ("PM: Introduce pm_power_off_prepare") caused problems in the poweroff path, as reported by YOSHIFUJI Hideaki / 吉藤英明. Generally, sysdev_shutdown() should be called after the ACPI preparation for powering the system off. To make it happen, we can separate sysdev_shutdown() from device_shutdown() and call it directly wherever necessary. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Tested-by: YOSHIFUJI Hideaki / 吉藤英明 <yoshfuji@linux-ipv6.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* coredump masking: reimplementation of dumpable using two flagsKawai, Hidehiro2007-07-191-12/+12
| | | | | | | | | | | | | | | | | This patch changes mm_struct.dumpable to a pair of bit flags. set_dumpable() converts three-value dumpable to two flags and stores it into lower two bits of mm_struct.flags instead of mm_struct.dumpable. get_dumpable() behaves in the opposite way. [akpm@linux-foundation.org: export set_dumpable] Signed-off-by: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: David Howells <dhowells@redhat.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* PM: Introduce pm_power_off_prepareRafael J. Wysocki2007-07-191-0/+9
| | | | | | | | | | | | | | | Introduce the pm_power_off_prepare() callback that can be registered by the interested platforms in analogy with pm_idle() and pm_power_off(), used for preparing the system to power off (needed by ACPI). This allows us to drop acpi_sysclass and device_acpi that are only defined in order to register the ACPI power off preparation callback, which is needed by pm_power_off() registered in a much different way. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* usermodehelper: Tidy up waitingJeremy Fitzhardinge2007-07-181-1/+1
| | | | | | | | | | | | | | | | | | | | | | | Rather than using a tri-state integer for the wait flag in call_usermodehelper_exec, define a proper enum, and use that. I've preserved the integer values so that any callers I've missed should still work OK. Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Cc: Randy Dunlap <randy.dunlap@oracle.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Andi Kleen <ak@suse.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Bjorn Helgaas <bjorn.helgaas@hp.com> Cc: Joel Becker <joel.becker@oracle.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: David Howells <dhowells@redhat.com>
* Add common orderly_poweroff()Jeremy Fitzhardinge2007-07-181-0/+58
| | | | | | | | | | | | | | | | | | | | | | | | | | | Various pieces of code around the kernel want to be able to trigger an orderly poweroff. This pulls them together into a single implementation. By default the poweroff command is /sbin/poweroff, but it can be set via sysctl: kernel/poweroff_cmd. This is split at whitespace, so it can include command-line arguments. This patch replaces four other instances of invoking either "poweroff" or "shutdown -h now": two sbus drivers, and acpi thermal management. sparc64 has its own "powerd"; still need to determine whether it should be replaced by orderly_poweroff(). Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Acked-by: Len Brown <lenb@kernel.org> Signed-off-by: Chris Wright <chrisw@sous-sol.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Randy Dunlap <randy.dunlap@oracle.com> Cc: Andi Kleen <ak@suse.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Arnd Bergmann <arnd@arndb.de> Cc: David S. Miller <davem@davemloft.net>
* move seccomp from /proc to a prctlAndrea Arcangeli2007-07-161-0/+8
| | | | | | | | | | This reduces the memory footprint and it enforces that only the current task can enable seccomp on itself (this is a requirement for a strightforward [modulo preempt ;) ] TIF_NOTSC implementation). Signed-off-by: Andrea Arcangeli <andrea@cpushare.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* user namespace: add the frameworkCedric Le Goater2007-07-161-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Basically, it will allow a process to unshare its user_struct table, resetting at the same time its own user_struct and all the associated accounting. A new root user (uid == 0) is added to the user namespace upon creation. Such root users have full privileges and it seems that theses privileges should be controlled through some means (process capabilities ?) The unshare is not included in this patch. Changes since [try #4]: - Updated get_user_ns and put_user_ns to accept NULL, and get_user_ns to return the namespace. Changes since [try #3]: - moved struct user_namespace to files user_namespace.{c,h} Changes since [try #2]: - removed struct user_namespace* argument from find_user() Changes since [try #1]: - removed struct user_namespace* argument from find_user() - added a root_user per user namespace Signed-off-by: Cedric Le Goater <clg@fr.ibm.com> Signed-off-by: Serge E. Hallyn <serue@us.ibm.com> Acked-by: Pavel Emelianov <xemul@openvz.org> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: Kirill Korotaev <dev@sw.ru> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Chris Wright <chrisw@sous-sol.org> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: James Morris <jmorris@namei.org> Cc: Andrew Morgan <agm@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* attach_pid() with struct pid parameterSukadev Bhattiprolu2007-05-111-1/+1
| | | | | | | | | | | | | | attach_pid() currently takes a pid_t and then uses find_pid() to find the corresponding struct pid. Sometimes we already have the struct pid. We can then skip find_pid() if attach_pid() were to take a struct pid parameter. Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: Dave Hansen <haveblue@us.ibm.com> Cc: Serge Hallyn <serue@us.ibm.com> Cc: <containers@lists.osdl.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* use defines in sys_getpriority/sys_setpriorityDaniel Walker2007-05-111-2/+3
| | | | | | | | | | | Switch to the defines for these two checks, instead of hard coding the values. [akpm@linux-foundation.org: add missing include] Signed-off-by: Daniel Walker <dwalker@mvista.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* getrusage(): fill ru_inblock and ru_oublock fields if possibleEric Dumazet2007-05-111-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If CONFIG_TASK_IO_ACCOUNTING is defined, we update io accounting counters for each task. This patch permits reporting of values using the well known getrusage() syscall, filling ru_inblock and ru_oublock instead of null values. As TASK_IO_ACCOUNTING currently counts bytes counts, we approximate blocks count doing : nr_blocks = nr_bytes / 512 Example of use : ---------------------- After patch is applied, /usr/bin/time command can now give a good approximation of IO that the process had to do. $ /usr/bin/time grep tototo /usr/include/* Command exited with non-zero status 1 0.00user 0.02system 0:02.11elapsed 1%CPU (0avgtext+0avgdata 0maxresident)k 24288inputs+0outputs (0major+259minor)pagefaults 0swaps $ /usr/bin/time dd if=/dev/zero of=/tmp/testfile count=1000 1000+0 enregistrements lus 1000+0 enregistrements écrits 512000 octets (512 kB) copiés, 0,00326601 seconde, 157 MB/s 0.00user 0.00system 0:00.00elapsed 80%CPU (0avgtext+0avgdata 0maxresident)k 0inputs+3000outputs (0major+299minor)pagefaults 0swaps Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/bunk/trivialLinus Torvalds2007-05-091-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * git://git.kernel.org/pub/scm/linux/kernel/git/bunk/trivial: (25 commits) sound: convert "sound" subdirectory to UTF-8 MAINTAINERS: Add cxacru website/mailing list include files: convert "include" subdirectory to UTF-8 general: convert "kernel" subdirectory to UTF-8 documentation: convert the Documentation directory to UTF-8 Convert the toplevel files CREDITS and MAINTAINERS to UTF-8. remove broken URLs from net drivers' output Magic number prefix consistency change to Documentation/magic-number.txt trivial: s/i_sem /i_mutex/ fix file specification in comments drivers/base/platform.c: fix small typo in doc misc doc and kconfig typos Remove obsolete fat_cvf help text Fix occurrences of "the the " Fix minor typoes in kernel/module.c Kconfig: Remove reference to external mqueue library Kconfig: A couple of grammatical fixes in arch/i386/Kconfig Correct comments in genrtc.c to refer to correct /proc file. Fix more "deprecated" spellos. Fix "deprecated" typoes. ... Fix trivial comment conflict in kernel/relay.c.
| * general: convert "kernel" subdirectory to UTF-8John Anthony Kazos Jr2007-05-091-1/+1
| | | | | | | | | | | | | | | | Convert the "kernel" subdirectory of the tree to UTF-8. The only file modified is <kernel/sys.c>. Signed-off-by: John Anthony Kazos Jr. <jakj@j-a-k-j.com> Signed-off-by: Adrian Bunk <bunk@stusta.de>
* | Extend notifier_call_chain to count nr_calls madeGautham R Shenoy2007-05-091-17/+77
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since 2.6.18-something, the community has been bugged by the problem to provide a clean and a stable mechanism to postpone a cpu-hotplug event as lock_cpu_hotplug was badly broken. This is another proposal towards solving that problem. This one is along the lines of the solution provided in kernel/workqueue.c Instead of having a global mechanism like lock_cpu_hotplug, we allow the subsytems to define their own per-subsystem hot cpu mutexes. These would be taken(released) where ever we are currently calling lock_cpu_hotplug(unlock_cpu_hotplug). Also, in the per-subsystem hotcpu callback function,we take this mutex before we handle any pre-cpu-hotplug events and release it once we finish handling the post-cpu-hotplug events. A standard means for doing this has been provided in [PATCH 2/4] and demonstrated in [PATCH 3/4]. The ordering of these per-subsystem mutexes might still prove to be a problem, but hopefully lockdep should help us get out of that muddle. The patch set to be applied against linux-2.6.19-rc5 is as follows: [PATCH 1/4] : Extend notifier_call_chain with an option to specify the number of notifications to be sent and also count the number of notifications actually sent. [PATCH 2/4] : Define events CPU_LOCK_ACQUIRE and CPU_LOCK_RELEASE and send out notifications for these in _cpu_up and _cpu_down. This would help us standardise the acquire and release of the subsystem locks in the hotcpu callback functions of these subsystems. [PATCH 3/4] : Eliminate lock_cpu_hotplug from kernel/sched.c. [PATCH 4/4] : In workqueue_cpu_callback function, acquire(release) the workqueue_mutex while handling CPU_LOCK_ACQUIRE(CPU_LOCK_RELEASE). If the per-subsystem-locking approach survives the test of time, we can expect a slow phasing out of lock_cpu_hotplug, which has not yet been eliminated in these patches :) This patch: Provide notifier_call_chain with an option to call only a specified number of notifiers and also record the number of call to notifiers made. The need for this enhancement was identified in the post entitled "Slab - Eliminate lock_cpu_hotplug from slab" (http://lkml.org/lkml/2006/10/28/92) by Ravikiran G Thirumalai and Andrew Morton. This patch adds two additional parameters to notifier_call_chain API namely - int nr_to_calls : Number of notifier_functions to be called. The don't care value is -1. - unsigned int *nr_calls : Records the total number of notifier_funtions called by notifier_call_chain. The don't care value is NULL. [michal.k.k.piotrowski@gmail.com: build fix] Credit: Andrew Morton <akpm@osdl.org> Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Michal Piotrowski <michal.k.k.piotrowski@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | PM: Separate hibernation code from suspend codeRafael J. Wysocki2007-05-091-1/+1
|/ | | | | | | | | | | | | | | | | | | | | | [ With Johannes Berg <johannes@sipsolutions.net> ] Separate the hibernation (aka suspend to disk code) from the other suspend code. In particular: * Remove the definitions related to hibernation from include/linux/pm.h * Introduce struct hibernation_ops and a new hibernate() function to hibernate the system, defined in include/linux/suspend.h * Separate suspend code in kernel/power/main.c from hibernation-related code in kernel/power/disk.c and kernel/power/user.c (with the help of hibernation_ops) * Switch ACPI (the only user of pm_ops.pm_disk_mode) to hibernation_ops Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Cc: Greg KH <greg@kroah.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: Nigel Cunningham <nigel@nigel.suspend2.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* CPU time limit patch / setrlimit(RLIMIT_CPU, 0) cheat fixTom Alsberg2007-05-081-9/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As discovered here today, the change in Kernel 2.6.17 intended to inhibit users from setting RLIMIT_CPU to 0 (as that is equivalent to unlimited) by "cheating" and setting it to 1 in such a case, does not make a difference, as the check is done in the wrong place (too late), and only applies to the profiling code. On all systems I checked running kernels above 2.6.17, no matter what the hard and soft CPU time limits were before, a user could escape them by issuing in the shell (sh/bash/zsh) "ulimit -t 0", and then the user's process was not ever killed. Attached is a trivial patch to fix that. Simply moving the check to a slightly earlier location (specifically, before the line that actually assigns the limit - *old_rlim = new_rlim), does the trick. Do note that at least the zsh (but not ash, dash, or bash) shell has the problem of "caching" the limits set by the ulimit command, so when running zsh the fix will not immediately be evident - after entering "ulimit -t 0", "ulimit -a" will show "-t: cpu time (seconds) 0", even though the actual limit as returned by getrlimit(...) will be 1. It can be verified by opening a subshell (which will not have the values of the parent shell in cache) and checking in it, or just by running a CPU intensive command like "echo '65536^1048576' | bc" and verifying that it dumps core after one second. Regardless of whether that is a misfeature in the shell, perhaps it would be better to return -EINVAL from setrlimit in such a case instead of cheating and setting to 1, as that does not really reflect the actual state of the process anymore. I do not however know what the ground for that decision was in the original 2.6.17 change, and whether there would be any "backward" compatibility issues, so I preferred not to touch that right now. Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* remove software_suspend()Johannes Berg2007-05-071-1/+1
| | | | | | | | | | | | | | | | Remove software_suspend() and all its users since pm_suspend(PM_SUSPEND_DISK) should be equivalent and there's no point in having two interfaces for the same thing. The patch also changes the valid_state function to return 0 (false) for PM_SUSPEND_DISK when SOFTWARE_SUSPEND is not configured instead of accepting it and having the whole thing fail later. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Acked-by: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Pavel Machek <pavel@ucw.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] pid: replace do/while_each_task_pid with do/while_each_pid_taskEric W. Biederman2007-02-121-16/+24
| | | | | | | | | | | | There isn't any real advantage to this change except that it allows the old functions to be removed. Which is easier on maintenance and puts the code in a more uniform style. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] tty: update the tty layer to work with struct pidEric W. Biederman2007-02-121-1/+0
| | | | | | | | | | | | | | | | | Of kernel subsystems that work with pids the tty layer is probably the largest consumer. But it has the nice virtue that the assiation with a session only lasts until the session leader exits. Which means that no reference counting is required. So using struct pid winds up being a simple optimization to avoid hash table lookups. In the long term the use of pid_nr also ensures that when we have multiple pid spaces mixed everything will work correctly. Signed-off-by: Eric W. Biederman <eric@maxwell.lnxi.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] Numerous fixes to kernel-doc info in source files.Robert P. J. Day2007-02-111-5/+5
| | | | | | | | | | | | | | | A variety of (mostly) innocuous fixes to the embedded kernel-doc content in source files, including: * make multi-line initial descriptions single line * denote some function names, constants and structs as such * change erroneous opening '/*' to '/**' in a few places * reword some text for clarity Signed-off-by: Robert P. J. Day <rpjday@mindspring.com> Cc: "Randy.Dunlap" <rdunlap@xenotime.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] notifiers: fix blocking_notifier_call_chain() scalabilityIngo Molnar2007-01-231-4/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | while lock-profiling the -rt kernel i noticed weird contention during mmap-intense workloads, and the tracer showed the following gem, in one of our MM hotpaths: threaded-2771 1.... 65us : sys_munmap (sysenter_do_call) threaded-2771 1.... 66us : profile_munmap (sys_munmap) threaded-2771 1.... 66us : blocking_notifier_call_chain (profile_munmap) threaded-2771 1.... 66us : rt_down_read (blocking_notifier_call_chain) ouch! a global rw-semaphore taken in one of the most performance- sensitive codepaths of the kernel. And i dont even have oprofile enabled! All distro kernels have CONFIG_PROFILING enabled, so this scalability problem affects the majority of Linux users. The fix is to enhance blocking_notifier_call_chain() to only take the lock if there appears to be work on the call-chain. With this patch applied i get nicely saturated system, and much higher munmap performance, on SMP systems. And as a bonus this also fixes a similar scalability bottleneck in the thread-exit codepath: profile_task_exit() ... Signed-off-by: Ingo Molnar <mingo@elte.hu> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] sys_setpgid: eliminate unnecessary do_each_task_pid(PIDTYPE_PGID)Oleg Nesterov2006-12-081-7/+4
| | | | | | | | | | All tasks in the process group have the same sid, we don't need to iterate them all to check that the caller of sys_setpgid() doesn't change its session. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] add process_session() helper routineCedric Le Goater2006-12-081-4/+4
| | | | | | | | | | | | | | | Replace occurences of task->signal->session by a new process_session() helper routine. It will be useful for pid namespaces to abstract the session pid number. Signed-off-by: Cedric Le Goater <clg@fr.ibm.com> Cc: Kirill Korotaev <dev@openvz.org> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] tty: ->signal->tty lockingPeter Zijlstra2006-12-081-2/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fix the locking of signal->tty. Use ->sighand->siglock to protect ->signal->tty; this lock is already used by most other members of ->signal/->sighand. And unless we are 'current' or the tasklist_lock is held we need ->siglock to access ->signal anyway. (NOTE: sys_unshare() is broken wrt ->sighand locking rules) Note that tty_mutex is held over tty destruction, so while holding tty_mutex any tty pointer remains valid. Otherwise the lifetime of ttys are governed by their open file handles. This leaves some holes for tty access from signal->tty (or any other non file related tty access). It solves the tty SLAB scribbles we were seeing. (NOTE: the change from group_send_sig_info to __group_send_sig_info needs to be examined by someone familiar with the security framework, I think it is safe given the SEND_SIG_PRIV from other __group_send_sig_info invocations) [schwidefsky@de.ibm.com: 3270 fix] [akpm@osdl.org: various post-viro fixes] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Alan Cox <alan@redhat.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Chris Wright <chrisw@sous-sol.org> Cc: Roland McGrath <roland@redhat.com> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: James Morris <jmorris@namei.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jeff Dike <jdike@addtoit.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Jan Kara <jack@ucw.cz> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] sys: remove unused variableDavid Rientjes2006-12-071-2/+2
| | | | | | | | | | Remove unused 'new_ruid' variable. Reported by David Binderman <dcb314@hotmail.com>. Signed-off-by: David Rientjes <rientjes@cs.washington.edu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* WorkStruct: Pass the work_struct pointer instead of context dataDavid Howells2006-11-221-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pass the work_struct pointer to the work function rather than context data. The work function can use container_of() to work out the data. For the cases where the container of the work_struct may go away the moment the pending bit is cleared, it is made possible to defer the release of the structure by deferring the clearing of the pending bit. To make this work, an extra flag is introduced into the management side of the work_struct. This governs auto-release of the structure upon execution. Ordinarily, the work queue executor would release the work_struct for further scheduling or deallocation by clearing the pending bit prior to jumping to the work function. This means that, unless the driver makes some guarantee itself that the work_struct won't go away, the work function may not access anything else in the work_struct or its container lest they be deallocated.. This is a problem if the auxiliary data is taken away (as done by the last patch). However, if the pending bit is *not* cleared before jumping to the work function, then the work function *may* access the work_struct and its container with no problems. But then the work function must itself release the work_struct by calling work_release(). In most cases, automatic release is fine, so this is the default. Special initiators exist for the non-auto-release case (ending in _NAR). Signed-Off-By: David Howells <dhowells@redhat.com>
* [PATCH] SRCU: report out-of-memory errorsAlan Stern2006-10-041-1/+2
| | | | | | | | | | | | | | | | | Currently the init_srcu_struct() routine has no way to report out-of-memory errors. This patch (as761) makes it return -ENOMEM when the per-cpu data allocation fails. The patch also makes srcu_init_notifier_head() report a BUG if a notifier head can't be initialized. Perhaps it should return -ENOMEM instead, but in the most likely cases where this might occur I don't think any recovery is possible. Notifier chains generally are not created dynamically. [akpm@osdl.org: avoid statement-with-side-effect in macro] Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Acked-by: Paul E. McKenney <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Add SRCU-based notifier chainsAlan Stern2006-10-041-1/+123
| | | | | | | | | | | | | | | | | | | | | | | This patch (as751) adds a new type of notifier chain, based on the SRCU (Sleepable Read-Copy Update) primitives recently added to the kernel. An SRCU notifier chain is much like a blocking notifier chain, in that it must be called in process context and its callout routines are allowed to sleep. The difference is that the chain's links are protected by the SRCU mechanism rather than by an rw-semaphore, so calling the chain has extremely low overhead: no memory barriers and no cache-line bouncing. On the other hand, unregistering from the chain is expensive and the chain head requires special runtime initialization (plus cleanup if it is to be deallocated). SRCU notifiers are appropriate for notifiers that will be called very frequently and for which unregistration occurs very seldom. The proposed "task notifier" scheme qualifies, as may some of the network notifiers. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Acked-by: Paul E. McKenney <paulmck@us.ibm.com> Acked-by: Chandra Seetharaman <sekharan@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] replace cad_pid by a struct pidCedric Le Goater2006-10-021-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | There are a few places in the kernel where the init task is signaled. The ctrl+alt+del sequence is one them. It kills a task, usually init, using a cached pid (cad_pid). This patch replaces the pid_t by a struct pid to avoid pid wrap around problem. The struct pid is initialized at boot time in init() and can be modified through systctl with /proc/sys/kernel/cad_pid [ I haven't found any distro using it ? ] It also introduces a small helper routine kill_cad_pid() which is used where it seemed ok to use cad_pid instead of pid 1. [akpm@osdl.org: cleanups, build fix] Signed-off-by: Cedric Le Goater <clg@fr.ibm.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Paul Mackerras <paulus@samba.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] namespaces: utsname: switch to using uts namespacesSerge E. Hallyn2006-10-021-7/+7
| | | | | | | | | | | | | | | | | | | | | Replace references to system_utsname to the per-process uts namespace where appropriate. This includes things like uname. Changes: Per Eric Biederman's comments, use the per-process uts namespace for ELF_PLATFORM, sunrpc, and parts of net/ipv4/ipconfig.c [jdike@addtoit.com: UML fix] [clg@fr.ibm.com: cleanup] [akpm@osdl.org: build fix] Signed-off-by: Serge E. Hallyn <serue@us.ibm.com> Cc: Kirill Korotaev <dev@openvz.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: Andrey Savochkin <saw@sw.ru> Signed-off-by: Cedric Le Goater <clg@fr.ibm.com> Cc: Jeff Dike <jdike@addtoit.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] disallow kprobes on notifier_call_chainbibo,mao2006-10-021-1/+1
| | | | | | | | | | | | When kprobe is re-entered, the re-entered kprobe kernel path will will call atomic_notifier_call_chain function, if this function is kprobed that will incur numerous kprobe recursive fault. This patch disallows kprobes on atomic_notifier_call_chain function. Signed-off-by: bibo, mao <bibo.mao@intel.com> Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] CodingStyle cleanup for kernel/sys.cCal Peake2006-10-011-50/+30
| | | | | | | | | Fix up kernel/sys.c to be consistent with CodingStyle and the rest of the file. Signed-off-by: Cal Peake <cp@absolutedigital.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Define vsyscall cache as blob to make clearer that user space ↵Andi Kleen2006-09-301-4/+4
| | | | | | shouldn't use it Signed-off-by: Andi Kleen <ak@suse.de>
* [PATCH] kill extraneous printk in kernel_restart()Cal Peake2006-09-291-1/+0
| | | | | | | | | Get rid of an extraneous printk in kernel_restart(). Signed-off-by: Cal Peake <cp@absolutedigital.net> Acked-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] x86: Add portable getcpu callAndi Kleen2006-09-261-0/+31
| | | | | | | | | | | | | | | | | | | | | | | | | | | For NUMA optimization and some other algorithms it is useful to have a fast to get the current CPU and node numbers in user space. x86-64 added a fast way to do this in a vsyscall. This adds a generic syscall for other architectures to make it a generic portable facility. I expect some of them will also implement it as a faster vsyscall. The cache is an optimization for the x86-64 vsyscall optimization. Since what the syscall returns is an approximation anyways and user space often wants very fast results it can be cached for some time. The norma methods to get this information in user space are relatively slow The vsyscall is in a better position to manage the cache because it has direct access to a fast time stamp (jiffies). For the generic syscall optimization it doesn't help much, but enforce a valid argument to keep programs portable I only added an i386 syscall entry for now. Other architectures can follow as needed. AK: Also added some cleanups from Andrew Morton Signed-off-by: Andi Kleen <ak@suse.de>
* [PATCH] Fix prctl privilege escalation and suid_dumpable (CVE-2006-2451)Marcel Holtmann2006-07-121-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Based on a patch from Ernie Petrides During security research, Red Hat discovered a behavioral flaw in core dump handling. A local user could create a program that would cause a core file to be dumped into a directory they would not normally have permissions to write to. This could lead to a denial of service (disk consumption), or allow the local user to gain root privileges. The prctl() system call should never allow to set "dumpable" to the value 2. Especially not for non-privileged users. This can be split into three cases: 1) running as root -- then core dumps will already be done as root, and so prctl(PR_SET_DUMPABLE, 2) is not useful 2) running as non-root w/setuid-to-root -- this is the debatable case 3) running as non-root w/setuid-to-non-root -- then you definitely do NOT want "dumpable" to get set to 2 because you have the privilege escalation vulnerability With case #2, the only potential usefulness is for a program that has designed to run with higher privilege (than the user invoking it) that wants to be able to create root-owned root-validated core dumps. This might be useful as a debugging aid, but would only be safe if the program had done a chdir() to a safe directory. There is no benefit to a production setuid-to-root utility, because it shouldn't be dumping core in the first place. If this is true, then the same debugging aid could also be accomplished with the "suid_dumpable" sysctl. Signed-off-by: Marcel Holtmann <marcel@holtmann.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* Remove obsolete #include <linux/config.h>Jörn Engel2006-06-301-1/+0
| | | | | Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de> Signed-off-by: Adrian Bunk <bunk@stusta.de>
* [PATCH] kernel/sys.c: cleanupsAdrian Bunk2006-06-251-3/+2
| | | | | | | | | | | | | | - proper prototypes for the following functions: - ctrl_alt_del() (in include/linux/reboot.h) - getrusage() (in include/linux/resource.h) - make the following needlessly global functions static: - kernel_restart_prepare() - kernel_kexec() [akpm@osdl.org: compile fix] Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Allow raw_notifier callouts to unregister themselvesAlan Stern2006-06-251-2/+3
| | | | | | | | | | | | Since raw_notifier chains don't benefit from any centralized locking protections, they shouldn't suffer from the associated limitations. Under some circumstances it might make sense for a raw_notifier callout routine to unregister itself from the notifier chain. This patch (as678) changes the notifier core to allow for such things. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] kernel/sys.c doesn't need init.hJes Sorensen2006-06-231-1/+0
| | | | | | | | | kernel/sys.c doesn't have anything in it relying on linux/init.h - remove the include. Signed-off-by: Jes Sorensen <jes@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpcLinus Torvalds2006-06-221-0/+13
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc: (139 commits) [POWERPC] re-enable OProfile for iSeries, using timer interrupt [POWERPC] support ibm,extended-*-frequency properties [POWERPC] Extra sanity check in EEH code [POWERPC] Dont look for class-code in pci children [POWERPC] Fix mdelay badness on shared processor partitions [POWERPC] disable floating point exceptions for init [POWERPC] Unify ppc syscall tables [POWERPC] mpic: add support for serial mode interrupts [POWERPC] pseries: Print PCI slot location code on failure [POWERPC] spufs: one more fix for 64k pages [POWERPC] spufs: fail spu_create with invalid flags [POWERPC] spufs: clear class2 interrupt status before wakeup [POWERPC] spufs: fix Makefile for "make clean" [POWERPC] spufs: remove stop_code from struct spu [POWERPC] spufs: fix spu irq affinity setting [POWERPC] spufs: further abstract priv1 register access [POWERPC] spufs: split the Cell BE support into generic and platform dependant parts [POWERPC] spufs: dont try to access SPE channel 1 count [POWERPC] spufs: use kzalloc in create_spu [POWERPC] spufs: fix initial state of wbox file ... Manually resolved conflicts in: drivers/net/phy/Makefile include/asm-powerpc/spu.h
| * [PATCH] Add a prctl to change the endianness of a process.Anton Blanchard2006-06-091-0/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This new prctl is intended for changing the execution mode of the processor, on processors that support both a little-endian mode and a big-endian mode. It is intended for use by programs such as instruction set emulators (for example an x86 emulator on PowerPC), which may find it convenient to use the processor in an alternate endianness mode when executing translated instructions. Note that this does not imply the existence of a fully-fledged ABI for both endiannesses, or of compatibility code for converting system calls done in the non-native endianness mode. The program is expected to arrange for all of its system call arguments to be presented in the native endianness. Switching between big and little-endian mode will require some care in constructing the instruction sequence for the switch. Generally the instructions up to the instruction that invokes the prctl system call will have to be in the old endianness, and subsequent instructions will have to be in the new endianness. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
* | [PATCH] avoid tasklist_lock at getrusage for multithreaded case tooRavikiran G Thirumalai2006-06-221-34/+22
|/ | | | | | | | | | | | Avoid taking tasklist_lock for at getrusage for the multithreaded case too. We don't need to take the tasklist lock for thread traversal of a process since Oleg's do-__unhash_process-under-siglock.patch and related work. Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Make setsid() more robustEric W. Biederman2006-03-311-4/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The core problem: setsid fails if it is called by init. The effect in 2.6.16 and the earlier kernels that have this problem is that if you do a "ps -j 1 or ps -ej 1" you will see that init and several of it's children have process group and session == 0. Instead of process group == session == 1. Despite init calling setsid. The reason it fails is that daemonize calls set_special_pids(1,1) on kernel threads that are launched before /sbin/init is called. The only remaining effect in that current->signal->leader == 0 for init instead of 1. And the setsid call fails. No one has noticed because /sbin/init does not check the return value of setsid. In 2.4 where we don't have the pidhash table, and daemonize doesn't exist setsid actually works for init. I care a lot about pid == 1 not being a special case that we leave broken, because of the container/jail work that I am doing. - Carefully allow init (pid == 1) to call setsid despite the kernel using its session. - Use find_task_by_pid instead of find_pid because find_pid taking a pidtype is going away. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] sys_times: don't take tasklist_lockOleg Nesterov2006-03-281-12/+1
| | | | | | | | sys_times: don't take tasklist_lock Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] revert "Optimize sys_times for a single thread process"Oleg Nesterov2006-03-281-60/+26
| | | | | | | | | | | | This patch reverts 'CONFIG_SMP && thread_group_empty()' optimization in sys_times(). The reason is that the next patch breaks memory ordering which is needed for that optimization. tasklist_lock in sys_times() will be eliminated completely by further patch. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Notifier chain update: API changesAlan Stern2006-03-271-61/+266
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* [PATCH] Use unsigned int types for a faster bsearchEric Dumazet2006-03-251-2/+2
| | | | | | | | | | | | | | | | | | | | | This patch avoids arithmetic on 'signed' types that are slower than 'unsigned'. This saves space and cpu cycles. size of kernel/sys.o before the patch (gcc-3.4.5) text data bss dec hex filename 10924 252 4 11180 2bac kernel/sys.o size of kernel/sys.o after the patch text data bss dec hex filename 10903 252 4 11159 2b97 kernel/sys.o I noticed that gcc-4.1.0 (from Fedora Core 5) even uses idiv instruction for (a+b)/2 if a and b are signed. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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