1 files changed, 79 insertions, 112 deletions

diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
index 753d9cb437d0..11ce470b41a5 100644
--- a/drivers/xen/pvcalls-front.c
+++ b/drivers/xen/pvcalls-front.c
@@ -60,6 +60,7 @@ struct sock_mapping {
         bool active_socket;
         struct list_head list;
         struct socket *sock;
+        atomic_t refcount;
         union {
                 struct {
                         int irq;
@@ -93,6 +94,32 @@ struct sock_mapping {
         };
 };
 
+static inline struct sock_mapping *pvcalls_enter_sock(struct socket *sock)
+{
+        struct sock_mapping *map;
+
+        if (!pvcalls_front_dev ||
+                dev_get_drvdata(&pvcalls_front_dev->dev) == NULL)
+                return ERR_PTR(-ENOTCONN);
+
+        map = (struct sock_mapping *)sock->sk->sk_send_head;
+        if (map == NULL)
+                return ERR_PTR(-ENOTSOCK);
+
+        pvcalls_enter();
+        atomic_inc(&map->refcount);
+        return map;
+}
+
+static inline void pvcalls_exit_sock(struct socket *sock)
+{
+        struct sock_mapping *map;
+
+        map = (struct sock_mapping *)sock->sk->sk_send_head;
+        atomic_dec(&map->refcount);
+        pvcalls_exit();
+}
+
 static inline int get_request(struct pvcalls_bedata *bedata, int *req_id)
 {
         *req_id = bedata->ring.req_prod_pvt & (RING_SIZE(&bedata->ring) - 1);
@@ -369,31 +396,23 @@ int pvcalls_front_connect(struct socket *sock, struct sockaddr *addr,
         if (addr->sa_family != AF_INET || sock->type != SOCK_STREAM)
                 return -EOPNOTSUPP;
 
-        pvcalls_enter();
-        if (!pvcalls_front_dev) {
-                pvcalls_exit();
-                return -ENOTCONN;
-        }
+        map = pvcalls_enter_sock(sock);
+        if (IS_ERR(map))
+                return PTR_ERR(map);
 
         bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
 
-        map = (struct sock_mapping *)sock->sk->sk_send_head;
-        if (!map) {
-                pvcalls_exit();
-                return -ENOTSOCK;
-        }
-
         spin_lock(&bedata->socket_lock);
         ret = get_request(bedata, &req_id);
         if (ret < 0) {
                 spin_unlock(&bedata->socket_lock);
-                pvcalls_exit();
+                pvcalls_exit_sock(sock);
                 return ret;
         }
         ret = create_active(map, &evtchn);
         if (ret < 0) {
                 spin_unlock(&bedata->socket_lock);
-                pvcalls_exit();
+                pvcalls_exit_sock(sock);
                 return ret;
         }
 
@@ -423,7 +442,7 @@ int pvcalls_front_connect(struct socket *sock, struct sockaddr *addr,
         smp_rmb();
         ret = bedata->rsp[req_id].ret;
         bedata->rsp[req_id].req_id = PVCALLS_INVALID_ID;
-        pvcalls_exit();
+        pvcalls_exit_sock(sock);
         return ret;
 }
 
@@ -488,23 +507,15 @@ int pvcalls_front_sendmsg(struct socket *sock, struct msghdr *msg,
         if (flags & (MSG_CONFIRM|MSG_DONTROUTE|MSG_EOR|MSG_OOB))
                 return -EOPNOTSUPP;
 
-        pvcalls_enter();
-        if (!pvcalls_front_dev) {
-                pvcalls_exit();
-                return -ENOTCONN;
-        }
+        map = pvcalls_enter_sock(sock);
+        if (IS_ERR(map))
+                return PTR_ERR(map);
         bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
 
-        map = (struct sock_mapping *) sock->sk->sk_send_head;
-        if (!map) {
-                pvcalls_exit();
-                return -ENOTSOCK;
-        }
-
         mutex_lock(&map->active.out_mutex);
         if ((flags & MSG_DONTWAIT) && !pvcalls_front_write_todo(map)) {
                 mutex_unlock(&map->active.out_mutex);
-                pvcalls_exit();
+                pvcalls_exit_sock(sock);
                 return -EAGAIN;
         }
         if (len > INT_MAX)
@@ -526,7 +537,7 @@ again:
                 tot_sent = sent;
 
         mutex_unlock(&map->active.out_mutex);
-        pvcalls_exit();
+        pvcalls_exit_sock(sock);
         return tot_sent;
 }
 
@@ -591,19 +602,11 @@ int pvcalls_front_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
         if (flags & (MSG_CMSG_CLOEXEC|MSG_ERRQUEUE|MSG_OOB|MSG_TRUNC))
                 return -EOPNOTSUPP;
 
-        pvcalls_enter();
-        if (!pvcalls_front_dev) {
-                pvcalls_exit();
-                return -ENOTCONN;
-        }
+        map = pvcalls_enter_sock(sock);
+        if (IS_ERR(map))
+                return PTR_ERR(map);
         bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
 
-        map = (struct sock_mapping *) sock->sk->sk_send_head;
-        if (!map) {
-                pvcalls_exit();
-                return -ENOTSOCK;
-        }
-
         mutex_lock(&map->active.in_mutex);
         if (len > XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER))
                 len = XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER);
@@ -623,7 +626,7 @@ int pvcalls_front_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
                 ret = 0;
 
         mutex_unlock(&map->active.in_mutex);
-        pvcalls_exit();
+        pvcalls_exit_sock(sock);
         return ret;
 }
 
@@ -637,24 +640,16 @@ int pvcalls_front_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
         if (addr->sa_family != AF_INET || sock->type != SOCK_STREAM)
                 return -EOPNOTSUPP;
 
-        pvcalls_enter();
-        if (!pvcalls_front_dev) {
-                pvcalls_exit();
-                return -ENOTCONN;
-        }
+        map = pvcalls_enter_sock(sock);
+        if (IS_ERR(map))
+                return PTR_ERR(map);
         bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
 
-        map = (struct sock_mapping *) sock->sk->sk_send_head;
-        if (map == NULL) {
-                pvcalls_exit();
-                return -ENOTSOCK;
-        }
-
         spin_lock(&bedata->socket_lock);
         ret = get_request(bedata, &req_id);
         if (ret < 0) {
                 spin_unlock(&bedata->socket_lock);
-                pvcalls_exit();
+                pvcalls_exit_sock(sock);
                 return ret;
         }
         req = RING_GET_REQUEST(&bedata->ring, req_id);
@@ -684,7 +679,7 @@ int pvcalls_front_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
         bedata->rsp[req_id].req_id = PVCALLS_INVALID_ID;
 
         map->passive.status = PVCALLS_STATUS_BIND;
-        pvcalls_exit();
+        pvcalls_exit_sock(sock);
         return 0;
 }
 
@@ -695,21 +690,13 @@ int pvcalls_front_listen(struct socket *sock, int backlog)
         struct xen_pvcalls_request *req;
         int notify, req_id, ret;
 
-        pvcalls_enter();
-        if (!pvcalls_front_dev) {
-                pvcalls_exit();
-                return -ENOTCONN;
-        }
+        map = pvcalls_enter_sock(sock);
+        if (IS_ERR(map))
+                return PTR_ERR(map);
         bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
 
-        map = (struct sock_mapping *) sock->sk->sk_send_head;
-        if (!map) {
-                pvcalls_exit();
-                return -ENOTSOCK;
-        }
-
         if (map->passive.status != PVCALLS_STATUS_BIND) {
-                pvcalls_exit();
+                pvcalls_exit_sock(sock);
                 return -EOPNOTSUPP;
         }
 
@@ -717,7 +704,7 @@ int pvcalls_front_listen(struct socket *sock, int backlog)
         ret = get_request(bedata, &req_id);
         if (ret < 0) {
                 spin_unlock(&bedata->socket_lock);
-                pvcalls_exit();
+                pvcalls_exit_sock(sock);
                 return ret;
         }
         req = RING_GET_REQUEST(&bedata->ring, req_id);
@@ -741,7 +728,7 @@ int pvcalls_front_listen(struct socket *sock, int backlog)
         bedata->rsp[req_id].req_id = PVCALLS_INVALID_ID;
 
         map->passive.status = PVCALLS_STATUS_LISTEN;
-        pvcalls_exit();
+        pvcalls_exit_sock(sock);
         return ret;
 }
 
@@ -753,21 +740,13 @@ int pvcalls_front_accept(struct socket *sock, struct socket *newsock, int flags)
         struct xen_pvcalls_request *req;
         int notify, req_id, ret, evtchn, nonblock;
 
-        pvcalls_enter();
-        if (!pvcalls_front_dev) {
-                pvcalls_exit();
-                return -ENOTCONN;
-        }
+        map = pvcalls_enter_sock(sock);
+        if (IS_ERR(map))
+                return PTR_ERR(map);
         bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
 
-        map = (struct sock_mapping *) sock->sk->sk_send_head;
-        if (!map) {
-                pvcalls_exit();
-                return -ENOTSOCK;
-        }
-
         if (map->passive.status != PVCALLS_STATUS_LISTEN) {
-                pvcalls_exit();
+                pvcalls_exit_sock(sock);
                 return -EINVAL;
         }
 
@@ -785,13 +764,13 @@ int pvcalls_front_accept(struct socket *sock, struct socket *newsock, int flags)
                         goto received;
                 }
                 if (nonblock) {
-                        pvcalls_exit();
+                        pvcalls_exit_sock(sock);
                         return -EAGAIN;
                 }
                 if (wait_event_interruptible(map->passive.inflight_accept_req,
                         !test_and_set_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
                                           (void *)&map->passive.flags))) {
-                        pvcalls_exit();
+                        pvcalls_exit_sock(sock);
                         return -EINTR;
                 }
         }
@@ -802,7 +781,7 @@ int pvcalls_front_accept(struct socket *sock, struct socket *newsock, int flags)
                 clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
                           (void *)&map->passive.flags);
                 spin_unlock(&bedata->socket_lock);
-                pvcalls_exit();
+                pvcalls_exit_sock(sock);
                 return ret;
         }
         map2 = kzalloc(sizeof(*map2), GFP_ATOMIC);
@@ -810,7 +789,7 @@ int pvcalls_front_accept(struct socket *sock, struct socket *newsock, int flags)
                 clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
                           (void *)&map->passive.flags);
                 spin_unlock(&bedata->socket_lock);
-                pvcalls_exit();
+                pvcalls_exit_sock(sock);
                 return -ENOMEM;
         }
         ret = create_active(map2, &evtchn);
@@ -819,7 +798,7 @@ int pvcalls_front_accept(struct socket *sock, struct socket *newsock, int flags)
                 clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
                           (void *)&map->passive.flags);
                 spin_unlock(&bedata->socket_lock);
-                pvcalls_exit();
+                pvcalls_exit_sock(sock);
                 return ret;
         }
         list_add_tail(&map2->list, &bedata->socket_mappings);
@@ -841,13 +820,13 @@ int pvcalls_front_accept(struct socket *sock, struct socket *newsock, int flags)
         /* We could check if we have received a response before returning. */
         if (nonblock) {
                 WRITE_ONCE(map->passive.inflight_req_id, req_id);
-                pvcalls_exit();
+                pvcalls_exit_sock(sock);
                 return -EAGAIN;
         }
 
         if (wait_event_interruptible(bedata->inflight_req,
                 READ_ONCE(bedata->rsp[req_id].req_id) == req_id)) {
-                pvcalls_exit();
+                pvcalls_exit_sock(sock);
                 return -EINTR;
         }
         /* read req_id, then the content */
@@ -862,7 +841,7 @@ received:
                 clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
                           (void *)&map->passive.flags);
                 pvcalls_front_free_map(bedata, map2);
-                pvcalls_exit();
+                pvcalls_exit_sock(sock);
                 return -ENOMEM;
         }
         newsock->sk->sk_send_head = (void *)map2;
@@ -874,7 +853,7 @@ received:
         clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT, (void *)&map->passive.flags);
         wake_up(&map->passive.inflight_accept_req);
 
-        pvcalls_exit();
+        pvcalls_exit_sock(sock);
         return ret;
 }
 
@@ -965,23 +944,16 @@ __poll_t pvcalls_front_poll(struct file *file, struct socket *sock,
         struct sock_mapping *map;
         __poll_t ret;
 
-        pvcalls_enter();
-        if (!pvcalls_front_dev) {
-                pvcalls_exit();
+        map = pvcalls_enter_sock(sock);
+        if (IS_ERR(map))
                 return EPOLLNVAL;
-        }
         bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
 
-        map = (struct sock_mapping *) sock->sk->sk_send_head;
-        if (!map) {
-                pvcalls_exit();
-                return EPOLLNVAL;
-        }
         if (map->active_socket)
                 ret = pvcalls_front_poll_active(file, bedata, map, wait);
         else
                 ret = pvcalls_front_poll_passive(file, bedata, map, wait);
-        pvcalls_exit();
+        pvcalls_exit_sock(sock);
         return ret;
 }
 
@@ -995,25 +967,20 @@ int pvcalls_front_release(struct socket *sock)
         if (sock->sk == NULL)
                 return 0;
 
-        pvcalls_enter();
-        if (!pvcalls_front_dev) {
-                pvcalls_exit();
-                return -EIO;
+        map = pvcalls_enter_sock(sock);
+        if (IS_ERR(map)) {
+                if (PTR_ERR(map) == -ENOTCONN)
+                        return -EIO;
+                else
+                        return 0;
         }
-
         bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
 
-        map = (struct sock_mapping *) sock->sk->sk_send_head;
-        if (map == NULL) {
-                pvcalls_exit();
-                return 0;
-        }
-
         spin_lock(&bedata->socket_lock);
         ret = get_request(bedata, &req_id);
         if (ret < 0) {
                 spin_unlock(&bedata->socket_lock);
-                pvcalls_exit();
+                pvcalls_exit_sock(sock);
                 return ret;
         }
         sock->sk->sk_send_head = NULL;
@@ -1043,10 +1010,10 @@ int pvcalls_front_release(struct socket *sock)
                 /*
                  * We need to make sure that sendmsg/recvmsg on this socket have
                  * not started before we've cleared sk_send_head here. The
-                 * easiest (though not optimal) way to guarantee this is to see
-                 * that no pvcall (other than us) is in progress.
+                 * easiest way to guarantee this is to see that no pvcalls
+                 * (other than us) is in progress on this socket.
                  */
-                while (atomic_read(&pvcalls_refcount) > 1)
+                while (atomic_read(&map->refcount) > 1)
                         cpu_relax();
 
                 pvcalls_front_free_map(bedata, map);