Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (44 commits)
  rcu: Fix accelerated GPs for last non-dynticked CPU
  rcu: Make non-RCU_PROVE_LOCKING rcu_read_lock_sched_held() understand boot
  rcu: Fix accelerated grace periods for last non-dynticked CPU
  rcu: Export rcu_scheduler_active
  rcu: Make rcu_read_lock_sched_held() take boot time into account
  rcu: Make lockdep_rcu_dereference() message less alarmist
  sched, cgroups: Fix module export
  rcu: Add RCU_CPU_STALL_VERBOSE to dump detailed per-task information
  rcu: Fix rcutorture mod_timer argument to delay one jiffy
  rcu: Fix deadlock in TREE_PREEMPT_RCU CPU stall detection
  rcu: Convert to raw_spinlocks
  rcu: Stop overflowing signed integers
  rcu: Use canonical URL for Mathieu's dissertation
  rcu: Accelerate grace period if last non-dynticked CPU
  rcu: Fix citation of Mathieu's dissertation
  rcu: Documentation update for CONFIG_PROVE_RCU
  security: Apply lockdep-based checking to rcu_dereference() uses
  idr: Apply lockdep-based diagnostics to rcu_dereference() uses
  radix-tree: Disable RCU lockdep checking in radix tree
  vfs: Abstract rcu_dereference_check for files-fdtable use
  ...

4 files changed, 42 insertions, 17 deletions

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index d62e3cdab357..5e3407d997b2 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -499,6 +499,18 @@ config PROVE_LOCKING
 
 	 For more details, see Documentation/lockdep-design.txt.
 
+config PROVE_RCU
+	bool "RCU debugging: prove RCU correctness"
+	depends on PROVE_LOCKING
+	default n
+	help
+	 This feature enables lockdep extensions that check for correct
+	 use of RCU APIs.  This is currently under development.  Say Y
+	 if you want to debug RCU usage or help work on the PROVE_RCU
+	 feature.
+
+	 Say N if you are unsure.
+
 config LOCKDEP
 	bool
 	depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
@@ -765,10 +777,22 @@ config RCU_CPU_STALL_DETECTOR
 	  CPUs are delaying the current grace period, but only when
 	  the grace period extends for excessive time periods.
 
-	  Say Y if you want RCU to perform such checks.
+	  Say N if you want to disable such checks.
+
+	  Say Y if you are unsure.
+
+config RCU_CPU_STALL_VERBOSE
+	bool "Print additional per-task information for RCU_CPU_STALL_DETECTOR"
+	depends on RCU_CPU_STALL_DETECTOR && TREE_PREEMPT_RCU
+	default n
+	help
+	  This option causes RCU to printk detailed per-task information
+	  for any tasks that are stalling the current RCU grace period.
 
 	  Say N if you are unsure.
 
+	  Say Y if you want to enable such checks.
+
 config KPROBES_SANITY_TEST
 	bool "Kprobes sanity tests"
 	depends on DEBUG_KERNEL
diff --git a/lib/debug_locks.c b/lib/debug_locks.c
index bc3b11731b9c..5bf0020b9248 100644
--- a/lib/debug_locks.c
+++ b/lib/debug_locks.c
@@ -23,6 +23,7 @@
  * shut up after that.
  */
 int debug_locks = 1;
+EXPORT_SYMBOL_GPL(debug_locks);
 
 /*
  * The locking-testsuite uses <debug_locks_silent> to get a
diff --git a/lib/idr.c b/lib/idr.c
index 0dc782216d4b..2eb1dca03681 100644
--- a/lib/idr.c
+++ b/lib/idr.c
@@ -504,7 +504,7 @@ void *idr_find(struct idr *idp, int id)
 	int n;
 	struct idr_layer *p;
 
-	p = rcu_dereference(idp->top);
+	p = rcu_dereference_raw(idp->top);
 	if (!p)
 		return NULL;
 	n = (p->layer+1) * IDR_BITS;
@@ -519,7 +519,7 @@ void *idr_find(struct idr *idp, int id)
 	while (n > 0 && p) {
 		n -= IDR_BITS;
 		BUG_ON(n != p->layer*IDR_BITS);
-		p = rcu_dereference(p->ary[(id >> n) & IDR_MASK]);
+		p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]);
 	}
 	return((void *)p);
 }
@@ -552,7 +552,7 @@ int idr_for_each(struct idr *idp,
 	struct idr_layer **paa = &pa[0];
 
 	n = idp->layers * IDR_BITS;
-	p = rcu_dereference(idp->top);
+	p = rcu_dereference_raw(idp->top);
 	max = 1 << n;
 
 	id = 0;
@@ -560,7 +560,7 @@ int idr_for_each(struct idr *idp,
 		while (n > 0 && p) {
 			n -= IDR_BITS;
 			*paa++ = p;
-			p = rcu_dereference(p->ary[(id >> n) & IDR_MASK]);
+			p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]);
 		}
 
 		if (p) {
diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index 92cdd9936e3d..6b9670d6bbf9 100644
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -364,7 +364,7 @@ static void *radix_tree_lookup_element(struct radix_tree_root *root,
 	unsigned int height, shift;
 	struct radix_tree_node *node, **slot;
 
-	node = rcu_dereference(root->rnode);
+	node = rcu_dereference_raw(root->rnode);
 	if (node == NULL)
 		return NULL;
 
@@ -384,7 +384,7 @@ static void *radix_tree_lookup_element(struct radix_tree_root *root,
 	do {
 		slot = (struct radix_tree_node **)
 			(node->slots + ((index>>shift) & RADIX_TREE_MAP_MASK));
-		node = rcu_dereference(*slot);
+		node = rcu_dereference_raw(*slot);
 		if (node == NULL)
 			return NULL;
 
@@ -568,7 +568,7 @@ int radix_tree_tag_get(struct radix_tree_root *root,
 	if (!root_tag_get(root, tag))
 		return 0;
 
-	node = rcu_dereference(root->rnode);
+	node = rcu_dereference_raw(root->rnode);
 	if (node == NULL)
 		return 0;
 
@@ -602,7 +602,7 @@ int radix_tree_tag_get(struct radix_tree_root *root,
 			BUG_ON(ret && saw_unset_tag);
 			return !!ret;
 		}
-		node = rcu_dereference(node->slots[offset]);
+		node = rcu_dereference_raw(node->slots[offset]);
 		shift -= RADIX_TREE_MAP_SHIFT;
 		height--;
 	}
@@ -711,7 +711,7 @@ __lookup(struct radix_tree_node *slot, void ***results, unsigned long index,
 		}
 
 		shift -= RADIX_TREE_MAP_SHIFT;
-		slot = rcu_dereference(slot->slots[i]);
+		slot = rcu_dereference_raw(slot->slots[i]);
 		if (slot == NULL)
 			goto out;
 	}
@@ -758,7 +758,7 @@ radix_tree_gang_lookup(struct radix_tree_root *root, void **results,
 	unsigned long cur_index = first_index;
 	unsigned int ret;
 
-	node = rcu_dereference(root->rnode);
+	node = rcu_dereference_raw(root->rnode);
 	if (!node)
 		return 0;
 
@@ -787,7 +787,7 @@ radix_tree_gang_lookup(struct radix_tree_root *root, void **results,
 			slot = *(((void ***)results)[ret + i]);
 			if (!slot)
 				continue;
-			results[ret + nr_found] = rcu_dereference(slot);
+			results[ret + nr_found] = rcu_dereference_raw(slot);
 			nr_found++;
 		}
 		ret += nr_found;
@@ -826,7 +826,7 @@ radix_tree_gang_lookup_slot(struct radix_tree_root *root, void ***results,
 	unsigned long cur_index = first_index;
 	unsigned int ret;
 
-	node = rcu_dereference(root->rnode);
+	node = rcu_dereference_raw(root->rnode);
 	if (!node)
 		return 0;
 
@@ -915,7 +915,7 @@ __lookup_tag(struct radix_tree_node *slot, void ***results, unsigned long index,
 			}
 		}
 		shift -= RADIX_TREE_MAP_SHIFT;
-		slot = rcu_dereference(slot->slots[i]);
+		slot = rcu_dereference_raw(slot->slots[i]);
 		if (slot == NULL)
 			break;
 	}
@@ -951,7 +951,7 @@ radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results,
 	if (!root_tag_get(root, tag))
 		return 0;
 
-	node = rcu_dereference(root->rnode);
+	node = rcu_dereference_raw(root->rnode);
 	if (!node)
 		return 0;
 
@@ -980,7 +980,7 @@ radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results,
 			slot = *(((void ***)results)[ret + i]);
 			if (!slot)
 				continue;
-			results[ret + nr_found] = rcu_dereference(slot);
+			results[ret + nr_found] = rcu_dereference_raw(slot);
 			nr_found++;
 		}
 		ret += nr_found;
@@ -1020,7 +1020,7 @@ radix_tree_gang_lookup_tag_slot(struct radix_tree_root *root, void ***results,
 	if (!root_tag_get(root, tag))
 		return 0;
 
-	node = rcu_dereference(root->rnode);
+	node = rcu_dereference_raw(root->rnode);
 	if (!node)
 		return 0;