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* rcu: Add CPU-stall capability to rcutorturePaul E. McKenney2012-02-212-0/+84
| | | | | | | | | | | | | Add module parameters to rcutorture that induce a CPU stall. The stall_cpu parameter specifies how long to stall in seconds, defaulting to zero, which indicates no stalling is to be undertaken. The stall_cpu_holdoff parameter specifies how many seconds after insmod (or boot, if rcutorture is built into the kernel) that this stall is to start. The default value for stall_cpu_holdoff is ten seconds. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: Make documentation give more realistic rcutorture durationPaul E. McKenney2012-02-211-1/+1
| | | | | | | | | The torture.txt documentation gives an example rcutorture run with a 100-second duration. This is ridiculously short, unless maybe testing a fix for a egregious bug. Use a more-realistic one-hour duration for the example. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcutorture: Permit holding off CPU-hotplug operations during bootPaul E. McKenney2012-02-212-4/+21
| | | | | | | | | | | When rcutorture is started automatically at boot time, it might well also start CPU-hotplug operations at that time, which might not be desirable. This commit therefore adds an rcutorture parameter that allows CPU-hotplug operations to be held off for the specified number of seconds after the start of boot. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: Print scheduling-clock information on RCU CPU stall-warning messagesPaul E. McKenney2012-02-214-14/+194
| | | | | | | | | | | There have been situations where RCU CPU stall warnings were caused by issues in scheduling-clock timer initialization. To make it easier to track these down, this commit causes the RCU CPU stall-warning messages to print out the number of scheduling-clock interrupts taken in the current grace period for each stalled CPU. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: Set RCU CPU stall times via sysfsPaul E. McKenney2012-02-212-11/+26
| | | | | | | | | | | | | | The default CONFIG_RCU_CPU_STALL_TIMEOUT value of 60 seconds has served Linux users well for production use for quite some time. However, for debugging, there will be more than three minutes between subsequent stall-warning messages. This can be an annoyingly long wait if you are trying to work out where the offending infinite loop is hiding. Therefore, this commit provides a rcu_cpu_stall_timeout sysfs parameter that may be adjusted at boot time and at runtime to speed up debugging. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: Remove #ifdef CONFIG_SMP from TREE_RCUPaul E. McKenney2012-02-212-31/+0
| | | | | | | | | Now that both TINY_RCU and TINY_PREEMPT_RCU have been in place for awhile, it is time to remove UP support from TREE_RCU, which is what this commit does. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: Note that rcu_access_pointer() can be used for teardownPaul E. McKenney2012-02-211-0/+7
| | | | | | | | | | | | | | | | | | | | | | There is no convenient expression for rcu_deference_protected() when it is used in tearing down multilinked structures following a grace period. For example, suppose that an element containing an RCU-protected pointer to a second element is removed from an enclosing RCU-protected data structure, then the write-side lock is released, and finally synchronize_rcu() is invoked to wait for a grace period. Then it is necessary to traverse the pointer in order to free up the second element. But we are not in an RCU read-side critical section and we are holding no locks, so the usual rcu_dereference_check() and rcu_dereference_protected() primitives are not appropriate. Neither is rcu_dereference_raw(), as it is intended for use in data structures where the user defines the locking design (for example, list_head). So this responsibility is added to rcu_access_pointer()'s list, and this commit updates rcu_assign_pointer()'s header comment accordingly. Suggested-by: David Howells <dhowells@redhat.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: David Howells <dhowells@redhat.com>
* rcu: Make rcu_sleep_check() also check rcu_lock_mapPaul E. McKenney2012-02-211-0/+14
| | | | | | | | | | | | | Although it is OK to be preempted in an RCU read-side critical section for TREE_PREEMPT_RCU, it is definitely not OK to be preempted, block, or might_sleep() within an RCU read-side critical section for TREE_RCU. Unfortunately, rcu_might_sleep() currently only checks for RCU-bh and RCU-sched read-side critical sections. This commit therefore makes rcu_might_sleep() check for RCU read-side critical sections, but only in TREE_RCU builds. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: Check for idle-loop entry while in RCU read-side critical sectionPaul E. McKenney2012-02-211-0/+11
| | | | | | | | | | | The inner idle loop is an extended quiescent state for all flavors of RCU, but there have been recent bug involving use of RCU read-side primitives from within the idle loop. Therefore, this commit enlists lockdep-RCU to detect attempts to enter the inner idle loop while in an RCU read-side critical section, emitting a lockdep-RCU splat if so. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: Clean up straggling rcu_preempt_needs_cpu() namePaul E. McKenney2012-02-213-6/+6
| | | | | | | | | | The recent updates to RCU_CPU_FAST_NO_HZ have an rcu_needs_cpu() that does more than just check for callbacks, so get the name for rcu_preempt_needs_cpu() consistent with that change, now calling it rcu_preempt_cpu_has_callbacks(). Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: Simplify unboosting checksPaul E. McKenney2012-02-212-6/+7
| | | | | | | | | | | | | | | | | | | This is a port of commit #82e78d80 from TREE_PREEMPT_RCU to TINY_PREEMPT_RCU. This commit uses the fact that current->rcu_boost_mutex is set any time that the RCU_READ_UNLOCK_BOOSTED flag is set in the current->rcu_read_unlock_special bitmask. This allows tests of the bit to be changed to tests of the pointer, which in turn allows the RCU_READ_UNLOCK_BOOSTED flag to be eliminated. Please note that the check of current->rcu_read_unlock_special need not change because any time that RCU_READ_UNLOCK_BOOSTED was set, so was RCU_READ_UNLOCK_BLOCKED. Therefore, __rcu_read_unlock() can continue testing current->rcu_read_unlock_special for non-zero, as before. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: Inform RCU of irq_exit() activityPaul E. McKenney2012-02-211-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is a port to TINY_RCU of Peter Zijlstra's commit #ec433f0c5 The rcu_read_unlock_special() function relies on in_irq() to exclude scheduler activity from interrupt level. This fails because exit_irq() can invoke the scheduler after clearing the preempt_count() bits that in_irq() uses to determine that it is at interrupt level. This situation can result in failures as follows: $task IRQ SoftIRQ rcu_read_lock() /* do stuff */ <preempt> |= UNLOCK_BLOCKED rcu_read_unlock() --t->rcu_read_lock_nesting irq_enter(); /* do stuff, don't use RCU */ irq_exit(); sub_preempt_count(IRQ_EXIT_OFFSET); invoke_softirq() ttwu(); spin_lock_irq(&pi->lock) rcu_read_lock(); /* do stuff */ rcu_read_unlock(); rcu_read_unlock_special() rcu_report_exp_rnp() ttwu() spin_lock_irq(&pi->lock) /* deadlock */ rcu_read_unlock_special(t); This can be triggered 'easily' because invoke_softirq() immediately does a ttwu() of ksoftirqd/# instead of doing the in-place softirq stuff first, but even without that the above happens. Cure this by also excluding softirqs from the rcu_read_unlock_special() handler and ensuring the force_irqthreads ksoftirqd/# wakeup is done from full softirq context. It is also necessary to delay the ->rcu_read_lock_nesting decrement until after rcu_read_unlock_special(). This delay is handled by the commit "Protect __rcu_read_unlock() against scheduler-using irq handlers". Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: Prevent RCU callbacks from executing before scheduler initializedPaul E. McKenney2012-02-212-7/+12
| | | | | | | | | | | | | | | | | | | This is a port of commit #b0d3041 from TREE_RCU to TREE_PREEMPT_RCU. Under some rare but real combinations of configuration parameters, RCU callbacks are posted during early boot that use kernel facilities that are not yet initialized. Therefore, when these callbacks are invoked, hard hangs and crashes ensue. This commit therefore prevents RCU callbacks from being invoked until after the scheduler is fully up and running, as in after multiple tasks have been spawned. It might well turn out that a better approach is to identify the specific RCU callbacks that are causing this problem, but that discussion will wait until such time as someone really needs an RCU callback to be invoked (as opposed to merely registered) during early boot. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: Streamline code produced by __rcu_read_unlock()Paul E. McKenney2012-02-211-1/+1
| | | | | | | | This is a port of commit #be0e1e21 to TINY_PREEMPT_RCU. This uses noinline to prevent rcu_read_unlock_special() from being inlined into __rcu_read_unlock(). Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: Protect __rcu_read_unlock() against scheduler-using irq handlersPaul E. McKenney2012-02-211-8/+35
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This commit ports commit #10f39bb1b2 (rcu: protect __rcu_read_unlock() against scheduler-using irq handlers) from TREE_PREEMPT_RCU to TINY_PREEMPT_RCU. The following is a corresponding port of that commit message. The addition of RCU read-side critical sections within runqueue and priority-inheritance critical sections introduced some deadlocks, for example, involving interrupts from __rcu_read_unlock() where the interrupt handlers call wake_up(). This situation can cause the instance of __rcu_read_unlock() invoked from interrupt to do some of the processing that would otherwise have been carried out by the task-level instance of __rcu_read_unlock(). When the interrupt-level instance of __rcu_read_unlock() is called with a scheduler lock held from interrupt-entry/exit situations where in_irq() returns false, deadlock can result. Of course, in a UP kernel, there are not really any deadlocks, but the upper-level critical section can still be be fatally confused by the lower-level critical section changing things out from under it. This commit resolves these deadlocks by using negative values of the per-task ->rcu_read_lock_nesting counter to indicate that an instance of __rcu_read_unlock() is in flight, which in turn prevents instances from interrupt handlers from doing any special processing. Note that nested rcu_read_lock()/rcu_read_unlock() pairs are still permitted, but they will never see ->rcu_read_lock_nesting go to zero, and will therefore never invoke rcu_read_unlock_special(), thus preventing them from seeing the RCU_READ_UNLOCK_BLOCKED bit should it be set in ->rcu_read_unlock_special. This patch also adds a check for ->rcu_read_unlock_special being negative in rcu_check_callbacks(), thus preventing the RCU_READ_UNLOCK_NEED_QS bit from being set should a scheduling-clock interrupt occur while __rcu_read_unlock() is exiting from an outermost RCU read-side critical section. Of course, __rcu_read_unlock() can be preempted during the time that ->rcu_read_lock_nesting is negative. This could result in the setting of the RCU_READ_UNLOCK_BLOCKED bit after __rcu_read_unlock() checks it, and would also result it this task being queued on the corresponding rcu_node structure's blkd_tasks list. Therefore, some later RCU read-side critical section would enter rcu_read_unlock_special() to clean up -- which could result in deadlock (OK, OK, fatal confusion) if that RCU read-side critical section happened to be in the scheduler where the runqueue or priority-inheritance locks were held. To prevent the possibility of fatal confusion that might result from preemption during the time that ->rcu_read_lock_nesting is negative, this commit also makes rcu_preempt_note_context_switch() check for negative ->rcu_read_lock_nesting, thus refraining from queuing the task (and from setting RCU_READ_UNLOCK_BLOCKED) if we are already exiting from the outermost RCU read-side critical section (in other words, we really are no longer actually in that RCU read-side critical section). In addition, rcu_preempt_note_context_switch() invokes rcu_read_unlock_special() to carry out the cleanup in this case, which clears out the ->rcu_read_unlock_special bits and dequeues the task (if necessary), in turn avoiding needless delay of the current RCU grace period and needless RCU priority boosting. It is still illegal to call rcu_read_unlock() while holding a scheduler lock if the prior RCU read-side critical section has ever had both preemption and irqs enabled. However, the common use case is legal, namely where then entire RCU read-side critical section executes with irqs disabled, for example, when the scheduler lock is held across the entire lifetime of the RCU read-side critical section. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: Remove single-rcu_node optimization in rcu_start_gp()Paul E. McKenney2012-02-211-18/+0
| | | | | | | | | | | | | | | | The grace-period initialization sequence in rcu_start_gp() has a special case for systems where the rcu_node tree is a single rcu_node structure. This made sense some years ago when systems were smaller and up to 64 CPUs could share a single rcu_node structure, but now that large systems are common and a given leaf rcu_node structure can support only 16 CPUs (due to lock contention on the rcu_node's ->lock field), this optimization is almost never taken. And even the small mobile platforms that might make use of it might rather have the kernel text reduction. Therefore, this commit removes the check for single-rcu_node trees. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
* rcu: Don't make callbacks go through second full grace periodPaul E. McKenney2012-02-211-6/+46
| | | | | | | | | | | | | | | | | RCU's current CPU-offline code path dumps all of the outgoing CPU's callbacks onto the RCU_NEXT_TAIL portion of the surviving CPU's callback list. This means that all the ready-to-invoke callbacks from the outgoing CPU must wait for another full RCU grace period. This was just fine when CPU-hotplug events were rare, but there is increasing evidence that users are planning to make increasing use of CPU hotplug. Therefore, this commit changes the callback-dumping procedure so that callbacks that are ready to invoke are moved to the RCU_DONE_TAIL portion of the surviving CPU's callback list. This avoids running these callbacks through a second unnecessary grace period. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: Check for callback invocation from offline CPUsPaul E. McKenney2012-02-211-0/+1
| | | | | | | | | | | | | | | Because quiescent states are now reported from offline CPUs in CPU_DYING state, there is some possibility that such a CPU might note the end of a grace period and attempt to start invoking callbacks. This would be a very bad thing, and is supposed to be prevented by the fact that the CPU_DYING CPU gets rid of all its callbacks before reporting the quiescent state. However, there is other CPU-offline code in the kernel, and it is quite possible that someone will invoke RCU core processing from that code. Therefore, this commit adds a warning for this case. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: Limit lazy-callback durationPaul E. McKenney2012-02-211-1/+11
| | | | | | | | | | Currently, a given CPU is permitted to remain in dyntick-idle mode indefinitely if it has only lazy RCU callbacks queued. This is vulnerable to corner cases in NUMA systems, so limit the time to six seconds by default. (Currently controlled by a cpp macro.) Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: Make rcutorture flag online/offline failuresPaul E. McKenney2012-02-211-0/+4
| | | | | | | | Make rcutorture check for CPU-hotplug failures and complain if there were any. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: Simplify offline processingPaul E. McKenney2012-02-213-99/+90
| | | | | | | | | | | Move ->qsmaskinit and blkd_tasks[] manipulation to the CPU_DYING notifier. This simplifies the code by eliminating a potential deadlock and by reducing the responsibilities of force_quiescent_state(). Also rename functions to make their connection to the CPU-hotplug stages explicit. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* mac80211: Convert call_rcu() to kfree_rcu(), drop mesh_gate_node_reclaim()Paul E. McKenney2012-02-211-7/+1
| | | | | | | | | | | | | | The call_rcu() in mesh_gate_del() invokes mesh_gate_node_reclaim(), which simply calls kfree(). So convert the call_rcu() to kfree_rcu(), allowing mesh_gate_node_reclaim() to be eliminated. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: "John W. Linville" <linville@tuxdriver.com> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: "David S. Miller" <davem@davemloft.net> Cc: linux-wireless@vger.kernel.org Cc: netdev@vger.kernel.org
* ipv4: Convert call_rcu() to kfree_rcu(), drop opt_kfree_rcuPaul E. McKenney2012-02-211-6/+1
| | | | | | | | | | | | | | | The call_rcu() in do_ip_setsockopt() invokes opt_kfree_rcu(), which just calls kfree(). So convert the call_rcu() to kfree_rcu(), which allows opt_kfree_rcu() to be eliminated. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: David S. Miller <davem@davemloft.net> Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> Cc: James Morris <jmorris@namei.org> Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org> Cc: Patrick McHardy <kaber@trash.net> Cc: netdev@vger.kernel.org
* ipv4: Convert call_rcu() to kfree_rcu(), drop opt_kfree_rcu()Paul E. McKenney2012-02-211-8/+3
| | | | | | | | | | | | | | | Because opt_kfree_rcu() just calls kfree(), all call_rcu() uses of it may be converted to kfree_rcu(). This permits opt_kfree_rcu() to be eliminated. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: David S. Miller <davem@davemloft.net> Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> Cc: James Morris <jmorris@namei.org> Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org> Cc: Patrick McHardy <kaber@trash.net> Cc: netdev@vger.kernel.org
* tcm_fc: Convert call_rcu() to kfree_rcu(), drop ft_tport_rcu_free()Paul E. McKenney2012-02-211-11/+1
| | | | | | | | | | | | | | The call_rcu() in ft_tport_delete() invokes ft_tport_rcu_free(), which just does a kfree(). So convert the call_rcu() to kfree_rcu(), allowing ft_tport_rcu_free() to be eliminated. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: "Nicholas A. Bellinger" <nab@linux-iscsi.org> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Jesper Juhl <jj@chaosbits.net> Cc: linux-scsi@vger.kernel.org Cc: target-devel@vger.kernel.org
* s390: Convert call_rcu() to kfree_rcu(), drop ext_int_hash_update()Paul E. McKenney2012-02-211-8/+1
| | | | | | | | | | | | The call_rcu() in unregister_external_interrupt() invokes ext_int_hash_update(), which just does a kfree(). Convert the call_rcu() to kfree_rcu(), allowing ext_int_hash_update() to be eliminated. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
* rcu: Move RCU_TRACE to lib/Kconfig.debugPaul E. McKenney2012-02-212-9/+10
| | | | | | | | | The RCU_TRACE kernel parameter has always been intended for debugging, not for production use. Formalize this by moving RCU_TRACE from init/Kconfig to lib/Kconfig.debug. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: Avoid waking up CPUs having only kfree_rcu() callbacksPaul E. McKenney2012-02-2110-47/+153
| | | | | | | | | | | | | | | | When CONFIG_RCU_FAST_NO_HZ is enabled, RCU will allow a given CPU to enter dyntick-idle mode even if it still has RCU callbacks queued. RCU avoids system hangs in this case by scheduling a timer for several jiffies in the future. However, if all of the callbacks on that CPU are from kfree_rcu(), there is no reason to wake the CPU up, as it is not a problem to defer freeing of memory. This commit therefore tracks the number of callbacks on a given CPU that are from kfree_rcu(), and avoids scheduling the timer if all of a given CPU's callbacks are from kfree_rcu(). Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: Add diagnostic for misaligned rcu_head structuresPaul E. McKenney2012-02-211-0/+1
| | | | | | | | | | | | The push for energy efficiency will require that RCU tag rcu_head structures to indicate whether or not their invocation is time critical. This tagging is best carried out in the bottom bits of the ->next pointers in the rcu_head structures. This tagging requires that the rcu_head structures be properly aligned, so this commit adds the required diagnostics. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: Add lockdep-RCU checks for simple self-deadlockPaul E. McKenney2012-02-215-0/+27
| | | | | | | | | | It is illegal to have a grace period within a same-flavor RCU read-side critical section, so this commit adds lockdep-RCU checks to splat when such abuse is encountered. This commit does not detect more elaborate RCU deadlock situations. These situations might be a job for lockdep enhancements. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: Improve synchronize_rcu() diagnosticsFrederic Weisbecker2012-02-211-0/+1
| | | | | | | | | | | | | Although TREE_PREEMPT_RCU indirectly uses might_sleep() to detect illegal use of synchronize_sched() and synchronize_rcu_bh() from within an RCU read-side critical section, this might_sleep() check is bypassed when there is only a single CPU (for example, when running an SMP kernel on a single-CPU system). This patch therefore adds a might_sleep() call to the rcu_blocking_is_gp() check that is unconditionally invoked from both synchronize_sched() and synchronize_rcu_bh(). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: Bring RTFP.txt up to date.Paul E. McKenney2012-02-211-98/+1686
| | | | | | Add publications from 2010 and 2011 to RTFP.txt. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* Linux 3.3-rc4v3.3-rc4Linus Torvalds2012-02-191-1/+1
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* Merge tag 'fixes-3.3-rc4' of ↵Linus Torvalds2012-02-1966-786/+524
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc These are the bug fixes that have accumulated since 3.3-rc3 in arm-soc. The majority of them are regression fixes for stuff that broke during the merge 3.3 window. The notable ones are: * The at91 ata drivers both broke because of an earlier cleanup patch that some other patches were based on. Jean-Christophe decided to remove the legacy at91_ide driver and fix the new-style at91-pata driver while keeping the cleanup patch. I almost rejected the patches for being too late and too big but in the end decided to accept them because they fix a regression. * A patch fixing build breakage from the sysdev-to-device conversion colliding with other changes touches a number of mach-s3c files. * b0654037 "ARM: orion: Fix Orion5x GPIO regression from MPP cleanup" is a mechanical change that unfortunately touches a lot of lines that should up in the diffstat. * tag 'fixes-3.3-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (28 commits) ARM: at91: drop ide driver in favor of the pata one pata/at91: use newly introduced SMC accessors ARM: at91: add accessor to manage SMC ARM: at91:rtc/rtc-at91sam9: ioremap register bank ARM: at91: USB AT91 gadget registration for module ep93xx: fix build of vision_ep93xx.c ARM: OMAP2xxx: PM: fix OMAP2xxx-specific UART idle bug in v3.3 ARM: orion: Fix USB phy for orion5x. ARM: orion: Fix Orion5x GPIO regression from MPP cleanup ARM: EXYNOS: Add cpu-offset property in gic device tree node ARM: EXYNOS: Bring exynos4-dt up to date ARM: OMAP3: cm-t35: fix section mismatch warning ARM: OMAP2: Fix the OMAP2 only build break seen with 2011+ ARM tool-chains ARM: tegra: paz00: fix wrong UART port on mini-pcie plug ARM: tegra: paz00: fix wrong SD1 power gpio i2c: tegra: Add devexit_p() for remove ARM: EXYNOS: Correct M-5MOLS sensor clock frequency on Universal C210 board ARM: EXYNOS: Correct framebuffer window size on Nuri board ARM: SAMSUNG: Fix missing api-change from subsys_interface change ARM: EXYNOS: Fix "warning: initialization from incompatible pointer type" ...
| * Merge branch 'at91-fixes' of git://github.com/at91linux/linux-at91 into fixesArnd Bergmann2012-02-1411-437/+140
| |\ | | | | | | | | | | | | | | | | | | | | | | | | * 'at91-fixes' of git://github.com/at91linux/linux-at91: ARM: at91: drop ide driver in favor of the pata one pata/at91: use newly introduced SMC accessors ARM: at91: add accessor to manage SMC ARM: at91:rtc/rtc-at91sam9: ioremap register bank ARM: at91: USB AT91 gadget registration for module
| | * ARM: at91: drop ide driver in favor of the pata oneJean-Christophe PLAGNIOL-VILLARD2012-02-134-375/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | Driver at91_ide is broken and should not be fixed: remove it. Modification of device files that where making use of it. The PATA driver (pata_at91) is able to replace at91_ide. Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com> Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
| | * pata/at91: use newly introduced SMC accessorsJean-Christophe PLAGNIOL-VILLARD2012-02-131-27/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | pata_at91 driver is broken since faee0cc: "make smc register base soc independent" Fix it with newly introduced SMC accessors. The overall action of removal of at91_sys_read/write will allow to use the pata_at91 on a single zImage kernel. Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com> Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com> Cc: linux-ide@vger.kernel.org
| | * ARM: at91: add accessor to manage SMCJean-Christophe PLAGNIOL-VILLARD2012-02-133-28/+100
| | | | | | | | | | | | | | | | | | | | | | | | SMC, Static Memory Controller will need more accessors to fine configure its parameters. Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com> Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
| | * ARM: at91:rtc/rtc-at91sam9: ioremap register bankJean-Christophe PLAGNIOL-VILLARD2012-02-131-3/+10
| | | | | | | | | | | | | | | | | | | | | | | | Instead of computing virtual address with AT91_VA_BASE_SYS, use the appropriate ioremap() call on the driver "memory" resource. Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com> Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
| | * ARM: at91: USB AT91 gadget registration for moduleNicolas Ferre2012-02-134-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Registration of at91_udc as a module will enable SoC related code. Fix following an idea from Karel Znamenacek. Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com> Acked-by: Karel Znamenacek <karel@ryston.cz> Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com> Cc: stable <stable@vger.kernel.org>
| * | Merge branch 'fixes' of ↵Arnd Bergmann2012-02-135-11/+9
| |\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap into fixes * 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap: ARM: OMAP2xxx: PM: fix OMAP2xxx-specific UART idle bug in v3.3 ARM: OMAP3: cm-t35: fix section mismatch warning ARM: OMAP2: Fix the OMAP2 only build break seen with 2011+ ARM tool-chains ARM: OMAP2+: board-generic: Add missing handle_irq callbacks
| | * | ARM: OMAP2xxx: PM: fix OMAP2xxx-specific UART idle bug in v3.3Paul Walmsley2012-02-101-7/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On OMAP2420-based systems, the PM code ignores the state of the UART functional clocks when determining what idle state to enter. This breaks the serial port now that the UART driver's clock behavior can be controlled via the PM autosuspend timeout. To fix, remove the special-case idle handling for the UARTs in the OMAP2420/2430 PM idle code added by commit 4af4016c53f52b26461b8030211f8427a58fa5ed ("OMAP3: PM: UART: disable clocks when idle and off-mode support"). Tested on Nokia N800. This patch is a collaboration between Tony Lindgren <tony@atomide.com> and Paul Walmsley <paul@pwsan.com>. Signed-off-by: Paul Walmsley <paul@pwsan.com> Acked-by: Kevin Hilman <khilman@ti.com> Signed-off-by: Tony Lindgren <tony@atomide.com>
| | * | ARM: OMAP3: cm-t35: fix section mismatch warningIgor Grinberg2012-02-081-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | WARNING: arch/arm/mach-omap2/built-in.o(.text+0xeae8): Section mismatch in reference from the function cm_t35_init_usbh() to the (unknown reference) .init.data:(unknown) The function cm_t35_init_usbh() references the (unknown reference) __initdata (unknown). This is often because cm_t35_init_usbh lacks a __initdata annotation or the annotation of (unknown) is wrong. Signed-off-by: Igor Grinberg <grinberg@compulab.co.il> Signed-off-by: Tony Lindgren <tony@atomide.com>
| | * | ARM: OMAP2: Fix the OMAP2 only build break seen with 2011+ ARM tool-chainsSantosh Shilimkar2012-02-082-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With the latest Sourcery G++ Lite 2011.03-41 and latest linaro tool-chains OMAP2 only build breaks with below error. arch/arm/mach-omap2/omap-smc.S: Assembler messages: arch/arm/mach-omap2/omap-smc.S:30: Error: selected processor does not support ARM mode `smc #0' arch/arm/mach-omap2/omap-smc.S:53: Error: selected processor does not support ARM mode `smc #0' arch/arm/mach-omap2/omap-smc.S:61: Error: selected processor does not support ARM mode `smc #0' arch/arm/mach-omap2/omap-smc.S:69: Error: selected processor does not support ARM mode `smc #0' arch/arm/mach-omap2/omap-smc.S:77: Error: selected processor does not support ARM mode `smc #0' make[1]: *** [arch/arm/mach-omap2/omap-smc.o] Error 1 OMAP2 devices doesn't have the security support but the security support was getting built because of OMAP2PLUS. Don't build security code for OMAP2 devices. While at it, fix the secure-common line in the Makefile to use tabs instead of spaces. Reported-by: Kevin Hilman <khilman@ti.com> Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Signed-off-by: Tony Lindgren <tony@atomide.com>
| | * | Merge branch 'fixes-dt' into fixesTony Lindgren2012-02-081-0/+4
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| | | * | ARM: OMAP2+: board-generic: Add missing handle_irq callbacksBenoit Cousson2011-12-071-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The following commit: 6b2f55d7851aa358d3a99cff344c560c4967f042, is adding the support for the CONFIG_MULTI_IRQ_HANDLER but did not update all the machine descriptors supported in the DT board-generic.c file. It thus break the DT boot on OMAP3 and OMAP4 boards. Add the proper handle_irq callbacks for OMAP3 and OMAP4 generic machine descriptors. Signed-off-by: Benoit Cousson <b-cousson@ti.com> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Tony Lindgren <tony@atomide.com>
| * | | | ep93xx: fix build of vision_ep93xx.cH Hartley Sweeten2012-02-131-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fix build breakage due to the following commits: Commit bd5f12a24766c1f299def0a78b008d4746f528f2 ARM: 7042/3: mach-ep93xx: break out GPIO driver specifics Commit 257af9f9725aa8a863b306659208a031135d59e7 ARM: 7041/1: gpio-ep93xx: hookup the to_irq callback in the driver The vision_ep9307 machine uses the ep93xx build-in gpios and needs to include <mach/gpio-ep93xx.h> to pickup the defines. The gpio_to_irq() call is now a callback to the gpio-ep93xx.c driver and cannot be used as a constant initializer for the .irq member of struct i2c_board_info. Signed-off-by: Hartley Sweeten <hsweeten@visionengravers.com> Acked-by: Ryan Mallon <rmallon@gmail.com> Acked-by: Mika Westerberg <mika.westerberg@iki.fi> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
| * | | | Merge branch 'v3.3-samsung-fixes-3' of ↵Arnd Bergmann2012-02-13378-5492/+2974
| |\ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/kgene/linux-samsung into fixes * 'v3.3-samsung-fixes-3' of git://git.kernel.org/pub/scm/linux/kernel/git/kgene/linux-samsung: (2 commits) ARM: EXYNOS: Add cpu-offset property in gic device tree node ARM: EXYNOS: Bring exynos4-dt up to date Linux 3.3-rc3 This includes an update to the v3.3-rc3 release from v3.3-rc2 Signed-off-by: Arnd Bergmann <arnd@arndb.de>
| | * | | | ARM: EXYNOS: Add cpu-offset property in gic device tree nodeThomas Abraham2012-02-091-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit db0d4db22a78 ('ARM: gic: allow GIC to support non-banked setups) requires a cpu-offset property to be specified for non-banked gic controllers, which is the case for Exynos4. Reported-and-Tested-by: Karol Lewandowski <k.lewandowsk@samsung.com> Signed-off-by: Thomas Abraham <thomas.abraham@linaro.org> Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
| | * | | | ARM: EXYNOS: Bring exynos4-dt up to dateKarol Lewandowski2012-02-091-2/+6
| | | |_|/ | | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This commit brings exynos4-dt in line with recent changes to mach-exynos tree, specifically: - Fixes build break related to replacing plat/exynos4.h with common.h in commit cc511b8d84d8 ("ARM: 7257/1: EXYNOS: introduce arch/arm/mach-exynos/common.[ch]") - Converts machine to use CONFIG_MULTI_IRQ_HANDLER as done for other machines in commit 4e44d2cb95bd ("ARM: exynos4: convert to CONFIG_MULTI_IRQ_HANDLER") - Adds restart specifier as done for other machines in commit 9eb4859564d6 ("ARM: 7262/1: restart: EXYNOS: use new restart hook") Signed-off-by: Karol Lewandowski <k.lewandowsk@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Cc: Thomas Abraham <thomas.abraham@linaro.org> Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>