Merge tag 'for-linus-5.2b-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull xen fixes from Juergen Gross:
 "One minor cleanup patch and a fix for handling of live migration when
  running as Xen guest"

* tag 'for-linus-5.2b-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xenbus: Avoid deadlock during suspend due to open transactions
  xen/pvcalls: Remove set but not used variable

4 files changed, 26 insertions, 6 deletions

diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
index c75549928656..57592a6b5c9e 100644
--- a/drivers/xen/pvcalls-front.c
+++ b/drivers/xen/pvcalls-front.c
@@ -531,7 +531,6 @@ out:
 int pvcalls_front_sendmsg(struct socket *sock, struct msghdr *msg,
                           size_t len)
 {
-        struct pvcalls_bedata *bedata;
         struct sock_mapping *map;
         int sent, tot_sent = 0;
         int count = 0, flags;
@@ -543,7 +542,6 @@ int pvcalls_front_sendmsg(struct socket *sock, struct msghdr *msg,
         map = pvcalls_enter_sock(sock);
         if (IS_ERR(map))
                 return PTR_ERR(map);
-        bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
 
         mutex_lock(&map->active.out_mutex);
         if ((flags & MSG_DONTWAIT) && !pvcalls_front_write_todo(map)) {
@@ -626,7 +624,6 @@ out:
 int pvcalls_front_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
                      int flags)
 {
-        struct pvcalls_bedata *bedata;
         int ret;
         struct sock_mapping *map;
 
@@ -636,7 +633,6 @@ int pvcalls_front_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
         map = pvcalls_enter_sock(sock);
         if (IS_ERR(map))
                 return PTR_ERR(map);
-        bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
 
         mutex_lock(&map->active.in_mutex);
         if (len > XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER))
diff --git a/drivers/xen/xenbus/xenbus.h b/drivers/xen/xenbus/xenbus.h
index 092981171df1..d75a2385b37c 100644
--- a/drivers/xen/xenbus/xenbus.h
+++ b/drivers/xen/xenbus/xenbus.h
@@ -83,6 +83,7 @@ struct xb_req_data {
         int num_vecs;
         int err;
         enum xb_req_state state;
+        bool user_req;
         void (*cb)(struct xb_req_data *);
         void *par;
 };
@@ -133,4 +134,6 @@ void xenbus_ring_ops_init(void);
 int xenbus_dev_request_and_reply(struct xsd_sockmsg *msg, void *par);
 void xenbus_dev_queue_reply(struct xb_req_data *req);
 
+extern unsigned int xb_dev_generation_id;
+
 #endif
diff --git a/drivers/xen/xenbus/xenbus_dev_frontend.c b/drivers/xen/xenbus/xenbus_dev_frontend.c
index faf452d0edf0..08adc590f631 100644
--- a/drivers/xen/xenbus/xenbus_dev_frontend.c
+++ b/drivers/xen/xenbus/xenbus_dev_frontend.c
@@ -62,6 +62,8 @@
 
 #include "xenbus.h"
 
+unsigned int xb_dev_generation_id;
+
 /*
  * An element of a list of outstanding transactions, for which we're
  * still waiting a reply.
@@ -69,6 +71,7 @@
 struct xenbus_transaction_holder {
         struct list_head list;
         struct xenbus_transaction handle;
+        unsigned int generation_id;
 };
 
 /*
@@ -441,6 +444,7 @@ static int xenbus_write_transaction(unsigned msg_type,
                         rc = -ENOMEM;
                         goto out;
                 }
+                trans->generation_id = xb_dev_generation_id;
                 list_add(&trans->list, &u->transactions);
         } else if (msg->hdr.tx_id != 0 &&
                    !xenbus_get_transaction(u, msg->hdr.tx_id))
@@ -449,6 +453,20 @@ static int xenbus_write_transaction(unsigned msg_type,
                  !(msg->hdr.len == 2 &&
                    (!strcmp(msg->body, "T") || !strcmp(msg->body, "F"))))
                 return xenbus_command_reply(u, XS_ERROR, "EINVAL");
+        else if (msg_type == XS_TRANSACTION_END) {
+                trans = xenbus_get_transaction(u, msg->hdr.tx_id);
+                if (trans && trans->generation_id != xb_dev_generation_id) {
+                        list_del(&trans->list);
+                        kfree(trans);
+                        if (!strcmp(msg->body, "T"))
+                                return xenbus_command_reply(u, XS_ERROR,
+                                                            "EAGAIN");
+                        else
+                                return xenbus_command_reply(u,
+                                                            XS_TRANSACTION_END,
+                                                            "OK");
+                }
+        }
 
         rc = xenbus_dev_request_and_reply(&msg->hdr, u);
         if (rc && trans) {
diff --git a/drivers/xen/xenbus/xenbus_xs.c b/drivers/xen/xenbus/xenbus_xs.c
index 49a3874ae6bb..ddc18da61834 100644
--- a/drivers/xen/xenbus/xenbus_xs.c
+++ b/drivers/xen/xenbus/xenbus_xs.c
@@ -105,6 +105,7 @@ static void xs_suspend_enter(void)
 
 static void xs_suspend_exit(void)
 {
+        xb_dev_generation_id++;
         spin_lock(&xs_state_lock);
         xs_suspend_active--;
         spin_unlock(&xs_state_lock);
@@ -125,7 +126,7 @@ static uint32_t xs_request_enter(struct xb_req_data *req)
                 spin_lock(&xs_state_lock);
         }
 
-        if (req->type == XS_TRANSACTION_START)
+        if (req->type == XS_TRANSACTION_START && !req->user_req)
                 xs_state_users++;
         xs_state_users++;
         rq_id = xs_request_id++;
@@ -140,7 +141,7 @@ void xs_request_exit(struct xb_req_data *req)
         spin_lock(&xs_state_lock);
         xs_state_users--;
         if ((req->type == XS_TRANSACTION_START && req->msg.type == XS_ERROR) ||
-            (req->type == XS_TRANSACTION_END &&
+            (req->type == XS_TRANSACTION_END && !req->user_req &&
              !WARN_ON_ONCE(req->msg.type == XS_ERROR &&
                            !strcmp(req->body, "ENOENT"))))
                 xs_state_users--;
@@ -286,6 +287,7 @@ int xenbus_dev_request_and_reply(struct xsd_sockmsg *msg, void *par)
         req->num_vecs = 1;
         req->cb = xenbus_dev_queue_reply;
         req->par = par;
+        req->user_req = true;
 
         xs_send(req, msg);
 
@@ -313,6 +315,7 @@ static void *xs_talkv(struct xenbus_transaction t,
         req->vec = iovec;
         req->num_vecs = num_vecs;
         req->cb = xs_wake_up;
+        req->user_req = false;
 
         msg.req_id = 0;
         msg.tx_id = t.id;