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: (52 commits)
  sched: fix RCU lockdep splat from task_group()
  rcu: using ACCESS_ONCE() to observe the jiffies_stall/rnp->qsmask value
  sched: suppress RCU lockdep splat in task_fork_fair
  net: suppress RCU lockdep false positive in sock_update_classid
  rcu: move check from rcu_dereference_bh to rcu_read_lock_bh_held
  rcu: Add advice to PROVE_RCU_REPEATEDLY kernel config parameter
  rcu: Add tracing data to support queueing models
  rcu: fix sparse errors in rcutorture.c
  rcu: only one evaluation of arg in rcu_dereference_check() unless sparse
  kernel: Remove undead ifdef CONFIG_DEBUG_LOCK_ALLOC
  rcu: fix _oddness handling of verbose stall warnings
  rcu: performance fixes to TINY_PREEMPT_RCU callback checking
  rcu: upgrade stallwarn.txt documentation for CPU-bound RT processes
  vhost: add __rcu annotations
  rcu: add comment stating that list_empty() applies to RCU-protected lists
  rcu: apply TINY_PREEMPT_RCU read-side speedup to TREE_PREEMPT_RCU
  rcu: combine duplicate code, courtesy of CONFIG_PREEMPT_RCU
  rcu: Upgrade srcu_read_lock() docbook about SRCU grace periods
  rcu: document ways of stalling updates in low-memory situations
  rcu: repair code-duplication FIXMEs
  ...

4 files changed, 36 insertions, 14 deletions

diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c
index 9ddafc30f432..af9ee313c10b 100644
--- a/drivers/input/evdev.c
+++ b/drivers/input/evdev.c
@@ -28,7 +28,7 @@ struct evdev {
         int minor;
         struct input_handle handle;
         wait_queue_head_t wait;
-        struct evdev_client *grab;
+        struct evdev_client __rcu *grab;
         struct list_head client_list;
         spinlock_t client_lock; /* protects client_list */
         struct mutex mutex;
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 7c8008225ee3..17927b1f9334 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -127,7 +127,10 @@ static void handle_tx(struct vhost_net *net)
         size_t len, total_len = 0;
         int err, wmem;
         size_t hdr_size;
-        struct socket *sock = rcu_dereference(vq->private_data);
+        struct socket *sock;
+
+        sock = rcu_dereference_check(vq->private_data,
+                                     lockdep_is_held(&vq->mutex));
         if (!sock)
                 return;
 
@@ -582,7 +585,10 @@ static void vhost_net_disable_vq(struct vhost_net *n,
 static void vhost_net_enable_vq(struct vhost_net *n,
                                 struct vhost_virtqueue *vq)
 {
-        struct socket *sock = vq->private_data;
+        struct socket *sock;
+
+        sock = rcu_dereference_protected(vq->private_data,
+                                         lockdep_is_held(&vq->mutex));
         if (!sock)
                 return;
         if (vq == n->vqs + VHOST_NET_VQ_TX) {
@@ -598,7 +604,8 @@ static struct socket *vhost_net_stop_vq(struct vhost_net *n,
         struct socket *sock;
 
         mutex_lock(&vq->mutex);
-        sock = vq->private_data;
+        sock = rcu_dereference_protected(vq->private_data,
+                                         lockdep_is_held(&vq->mutex));
         vhost_net_disable_vq(n, vq);
         rcu_assign_pointer(vq->private_data, NULL);
         mutex_unlock(&vq->mutex);
@@ -736,7 +743,8 @@ static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd)
         }
 
         /* start polling new socket */
-        oldsock = vq->private_data;
+        oldsock = rcu_dereference_protected(vq->private_data,
+                                            lockdep_is_held(&vq->mutex));
         if (sock != oldsock) {
                 vhost_net_disable_vq(n, vq);
                 rcu_assign_pointer(vq->private_data, sock);
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index dd3d6f7406f8..8b5a1b33d0fe 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -320,7 +320,7 @@ long vhost_dev_reset_owner(struct vhost_dev *dev)
         vhost_dev_cleanup(dev);
 
         memory->nregions = 0;
-        dev->memory = memory;
+        RCU_INIT_POINTER(dev->memory, memory);
         return 0;
 }
 
@@ -352,8 +352,9 @@ void vhost_dev_cleanup(struct vhost_dev *dev)
                 fput(dev->log_file);
         dev->log_file = NULL;
         /* No one will access memory at this point */
-        kfree(dev->memory);
-        dev->memory = NULL;
+        kfree(rcu_dereference_protected(dev->memory,
+                                        lockdep_is_held(&dev->mutex)));
+        RCU_INIT_POINTER(dev->memory, NULL);
         if (dev->mm)
                 mmput(dev->mm);
         dev->mm = NULL;
@@ -440,14 +441,22 @@ static int vq_access_ok(unsigned int num,
 /* Caller should have device mutex but not vq mutex */
 int vhost_log_access_ok(struct vhost_dev *dev)
 {
-        return memory_access_ok(dev, dev->memory, 1);
+        struct vhost_memory *mp;
+
+        mp = rcu_dereference_protected(dev->memory,
+                                       lockdep_is_held(&dev->mutex));
+        return memory_access_ok(dev, mp, 1);
 }
 
 /* Verify access for write logging. */
 /* Caller should have vq mutex and device mutex */
 static int vq_log_access_ok(struct vhost_virtqueue *vq, void __user *log_base)
 {
-        return vq_memory_access_ok(log_base, vq->dev->memory,
+        struct vhost_memory *mp;
+
+        mp = rcu_dereference_protected(vq->dev->memory,
+                                       lockdep_is_held(&vq->mutex));
+        return vq_memory_access_ok(log_base, mp,
                             vhost_has_feature(vq->dev, VHOST_F_LOG_ALL)) &&
                 (!vq->log_used || log_access_ok(log_base, vq->log_addr,
                                         sizeof *vq->used +
@@ -487,7 +496,8 @@ static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m)
                 kfree(newmem);
                 return -EFAULT;
         }
-        oldmem = d->memory;
+        oldmem = rcu_dereference_protected(d->memory,
+                                           lockdep_is_held(&d->mutex));
         rcu_assign_pointer(d->memory, newmem);
         synchronize_rcu();
         kfree(oldmem);
diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index afd77295971c..af3c11ded5fd 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -106,7 +106,7 @@ struct vhost_virtqueue {
          * vhost_work execution acts instead of rcu_read_lock() and the end of
          * vhost_work execution acts instead of rcu_read_lock().
          * Writers use virtqueue mutex. */
-        void *private_data;
+        void __rcu *private_data;
         /* Log write descriptors */
         void __user *log_base;
         struct vhost_log log[VHOST_NET_MAX_SG];
@@ -116,7 +116,7 @@ struct vhost_dev {
         /* Readers use RCU to access memory table pointer
          * log base pointer and features.
          * Writers use mutex below.*/
-        struct vhost_memory *memory;
+        struct vhost_memory __rcu *memory;
         struct mm_struct *mm;
         struct mutex mutex;
         unsigned acked_features;
@@ -173,7 +173,11 @@ enum {
 
 static inline int vhost_has_feature(struct vhost_dev *dev, int bit)
 {
-        unsigned acked_features = rcu_dereference(dev->acked_features);
+        unsigned acked_features;
+
+        acked_features =
+                rcu_dereference_index_check(dev->acked_features,
+                                            lockdep_is_held(&dev->mutex));
         return acked_features & (1 << bit);
 }