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Commit 28457ee6 authored by Arnd Bergmann's avatar Arnd Bergmann Committed by Paul E. McKenney
Browse files

vhost: add __rcu annotations 



Also add rcu_dereference_protected() for code paths where locks are held.

Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
parent 65e6bf48

drivers/vhost/net.c

+12 −4
Original line number Original line Diff line number Diff line
@@ -127,7 +127,10 @@ static void handle_tx(struct vhost_net *net) 
	size_t len, total_len = 0;

	size_t len, total_len = 0;

	int err, wmem;

	int err, wmem;

	size_t hdr_size;

	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)

	if (!sock)

		return;

		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,

static void vhost_net_enable_vq(struct vhost_net *n,

				struct vhost_virtqueue *vq)

				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)

	if (!sock)

		return;

		return;

	if (vq == n->vqs + VHOST_NET_VQ_TX) {

	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;

	struct socket *sock;





	mutex_lock(&vq->mutex);

	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);

	vhost_net_disable_vq(n, vq);

	rcu_assign_pointer(vq->private_data, NULL);

	rcu_assign_pointer(vq->private_data, NULL);

	mutex_unlock(&vq->mutex);

	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 */

	/* start polling new socket */

	oldsock = vq->private_data;

	oldsock = rcu_dereference_protected(vq->private_data,

					    lockdep_is_held(&vq->mutex));

	if (sock != oldsock) {

	if (sock != oldsock) {

                vhost_net_disable_vq(n, vq);

                vhost_net_disable_vq(n, vq);

                rcu_assign_pointer(vq->private_data, sock);

                rcu_assign_pointer(vq->private_data, sock);

drivers/vhost/vhost.c

+16 −6
Original line number Original line Diff line number Diff line
@@ -284,7 +284,7 @@ long vhost_dev_reset_owner(struct vhost_dev *dev) 
	vhost_dev_cleanup(dev);

	vhost_dev_cleanup(dev);





	memory->nregions = 0;

	memory->nregions = 0;

	dev->memory = memory;

	RCU_INIT_POINTER(dev->memory, memory);

	return 0;

	return 0;

}

}
@@ -316,8 +316,9 @@ void vhost_dev_cleanup(struct vhost_dev *dev) 
		fput(dev->log_file);

		fput(dev->log_file);

	dev->log_file = NULL;

	dev->log_file = NULL;

	/* No one will access memory at this point */

	/* No one will access memory at this point */

	kfree(dev->memory);

	kfree(rcu_dereference_protected(dev->memory,

	dev->memory = NULL;

					lockdep_is_held(&dev->mutex)));

	RCU_INIT_POINTER(dev->memory, NULL);

	if (dev->mm)

	if (dev->mm)

		mmput(dev->mm);

		mmput(dev->mm);

	dev->mm = NULL;

	dev->mm = NULL;
@@ -401,14 +402,22 @@ static int vq_access_ok(unsigned int num, 
/* Caller should have device mutex but not vq mutex */

/* Caller should have device mutex but not vq mutex */

int vhost_log_access_ok(struct vhost_dev *dev)

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. */

/* Verify access for write logging. */

/* Caller should have vq mutex and device mutex */

/* Caller should have vq mutex and device mutex */

static int vq_log_access_ok(struct vhost_virtqueue *vq, void __user *log_base)

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)) &&

			    vhost_has_feature(vq->dev, VHOST_F_LOG_ALL)) &&

		(!vq->log_used || log_access_ok(log_base, vq->log_addr,

		(!vq->log_used || log_access_ok(log_base, vq->log_addr,

					sizeof *vq->used +

					sizeof *vq->used +
@@ -448,7 +457,8 @@ static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m) 
		kfree(newmem);

		kfree(newmem);

		return -EFAULT;

		return -EFAULT;

	}

	}

	oldmem = d->memory;

	oldmem = rcu_dereference_protected(d->memory,

					   lockdep_is_held(&d->mutex));

	rcu_assign_pointer(d->memory, newmem);

	rcu_assign_pointer(d->memory, newmem);

	synchronize_rcu();

	synchronize_rcu();

	kfree(oldmem);

	kfree(oldmem);

drivers/vhost/vhost.h

+7 −3
Original line number Original line Diff line number Diff line
@@ -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() and the end of

	 * vhost_work execution acts instead of rcu_read_lock().

	 * vhost_work execution acts instead of rcu_read_lock().

	 * Writers use virtqueue mutex. */

	 * Writers use virtqueue mutex. */

	void *private_data;

	void __rcu *private_data;

	/* Log write descriptors */

	/* Log write descriptors */

	void __user *log_base;

	void __user *log_base;

	struct vhost_log log[VHOST_NET_MAX_SG];

	struct vhost_log log[VHOST_NET_MAX_SG];
@@ -116,7 +116,7 @@ struct vhost_dev { 
	/* Readers use RCU to access memory table pointer

	/* Readers use RCU to access memory table pointer

	 * log base pointer and features.

	 * log base pointer and features.

	 * Writers use mutex below.*/

	 * Writers use mutex below.*/

	struct vhost_memory *memory;

	struct vhost_memory __rcu *memory;

	struct mm_struct *mm;

	struct mm_struct *mm;

	struct mutex mutex;

	struct mutex mutex;

	unsigned acked_features;

	unsigned acked_features;
@@ -173,7 +173,11 @@ enum { 




static inline int vhost_has_feature(struct vhost_dev *dev, int bit)

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);

	return acked_features & (1 << bit);

}

}