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Commit 6db3d8dc authored by Stefan Hajnoczi's avatar Stefan Hajnoczi Committed by Michael S. Tsirkin
Browse files

vhost/vsock: switch to a mutex for vhost_vsock_hash 



Now that there are no more data path users of vhost_vsock_lock, it can
be turned into a mutex.  It's only used by .release() and in the
.ioctl() path.

Depends-on: <20181105103547.22018-1-stefanha@redhat.com>
Suggested-by: default avatarJason Wang <jasowang@redhat.com>
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Acked-by: default avatarJason Wang <jasowang@redhat.com>
parent 1f23816b

drivers/vhost/vsock.c

+8 −8
Original line number Diff line number Diff line
@@ -27,14 +27,14 @@ enum { 
};



/* Used to track all the vhost_vsock instances on the system. */

static DEFINE_SPINLOCK(vhost_vsock_lock);

static DEFINE_MUTEX(vhost_vsock_mutex);

static DEFINE_READ_MOSTLY_HASHTABLE(vhost_vsock_hash, 8);



struct vhost_vsock {

	struct vhost_dev dev;

	struct vhost_virtqueue vqs[2];



	/* Link to global vhost_vsock_hash, writes use vhost_vsock_lock */

	/* Link to global vhost_vsock_hash, writes use vhost_vsock_mutex */

	struct hlist_node hash;



	struct vhost_work send_pkt_work;
@@ -51,7 +51,7 @@ static u32 vhost_transport_get_local_cid(void) 
	return VHOST_VSOCK_DEFAULT_HOST_CID;

}



/* Callers that dereference the return value must hold vhost_vsock_lock or the

/* Callers that dereference the return value must hold vhost_vsock_mutex or the

 * RCU read lock.

 */

static struct vhost_vsock *vhost_vsock_get(u32 guest_cid)
@@ -584,10 +584,10 @@ static int vhost_vsock_dev_release(struct inode *inode, struct file *file) 
{

	struct vhost_vsock *vsock = file->private_data;



	spin_lock_bh(&vhost_vsock_lock);

	mutex_lock(&vhost_vsock_mutex);

	if (vsock->guest_cid)

		hash_del_rcu(&vsock->hash);

	spin_unlock_bh(&vhost_vsock_lock);

	mutex_unlock(&vhost_vsock_mutex);



	/* Wait for other CPUs to finish using vsock */

	synchronize_rcu();
@@ -631,10 +631,10 @@ static int vhost_vsock_set_cid(struct vhost_vsock *vsock, u64 guest_cid) 
		return -EINVAL;



	/* Refuse if CID is already in use */

	spin_lock_bh(&vhost_vsock_lock);

	mutex_lock(&vhost_vsock_mutex);

	other = vhost_vsock_get(guest_cid);

	if (other && other != vsock) {

		spin_unlock_bh(&vhost_vsock_lock);

		mutex_unlock(&vhost_vsock_mutex);

		return -EADDRINUSE;

	}
@@ -643,7 +643,7 @@ static int vhost_vsock_set_cid(struct vhost_vsock *vsock, u64 guest_cid) 


	vsock->guest_cid = guest_cid;

	hash_add_rcu(vhost_vsock_hash, &vsock->hash, guest_cid);

	spin_unlock_bh(&vhost_vsock_lock);

	mutex_unlock(&vhost_vsock_mutex);



	return 0;

}