1 files changed, 23 insertions, 55 deletions

diff --git a/drivers/xen/xenbus/xenbus_xs.c b/drivers/xen/xenbus/xenbus_xs.c
index d32c726f7a12..15f18374020e 100644
--- a/drivers/xen/xenbus/xenbus_xs.c
+++ b/drivers/xen/xenbus/xenbus_xs.c
@@ -112,6 +112,12 @@ static void xs_suspend_exit(void)
 	wake_up_all(&xs_state_enter_wq);
 }
 
+void xs_free_req(struct kref *kref)
+{
+	struct xb_req_data *req = container_of(kref, struct xb_req_data, kref);
+	kfree(req);
+}
+
 static uint32_t xs_request_enter(struct xb_req_data *req)
 {
 	uint32_t rq_id;
@@ -237,6 +243,12 @@ static void xs_send(struct xb_req_data *req, struct xsd_sockmsg *msg)
 	req->caller_req_id = req->msg.req_id;
 	req->msg.req_id = xs_request_enter(req);
 
+	/*
+	 * Take 2nd ref.  One for this thread, and the second for the
+	 * xenbus_thread.
+	 */
+	kref_get(&req->kref);
+
 	mutex_lock(&xb_write_mutex);
 	list_add_tail(&req->list, &xb_write_list);
 	notify = list_is_singular(&xb_write_list);
@@ -261,8 +273,8 @@ static void *xs_wait_for_reply(struct xb_req_data *req, struct xsd_sockmsg *msg)
 	if (req->state == xb_req_state_queued ||
 	    req->state == xb_req_state_wait_reply)
 		req->state = xb_req_state_aborted;
-	else
-		kfree(req);
+
+	kref_put(&req->kref, xs_free_req);
 	mutex_unlock(&xb_write_mutex);
 
 	return ret;
@@ -291,6 +303,7 @@ int xenbus_dev_request_and_reply(struct xsd_sockmsg *msg, void *par)
 	req->cb = xenbus_dev_queue_reply;
 	req->par = par;
 	req->user_req = true;
+	kref_init(&req->kref);
 
 	xs_send(req, msg);
 
@@ -319,6 +332,7 @@ static void *xs_talkv(struct xenbus_transaction t,
 	req->num_vecs = num_vecs;
 	req->cb = xs_wake_up;
 	req->user_req = false;
+	kref_init(&req->kref);
 
 	msg.req_id = 0;
 	msg.tx_id = t.id;
@@ -393,10 +407,10 @@ static char *join(const char *dir, const char *name)
 		buffer = kasprintf(GFP_NOIO | __GFP_HIGH, "%s", dir);
 	else
 		buffer = kasprintf(GFP_NOIO | __GFP_HIGH, "%s/%s", dir, name);
-	return (!buffer) ? ERR_PTR(-ENOMEM) : buffer;
+	return buffer ?: ERR_PTR(-ENOMEM);
 }
 
-static char **split(char *strings, unsigned int len, unsigned int *num)
+static char **split_strings(char *strings, unsigned int len, unsigned int *num)
 {
 	char *p, **ret;
 
@@ -434,7 +448,7 @@ char **xenbus_directory(struct xenbus_transaction t,
 	if (IS_ERR(strings))
 		return ERR_CAST(strings);
 
-	return split(strings, len, num);
+	return split_strings(strings, len, num);
 }
 EXPORT_SYMBOL_GPL(xenbus_directory);
 
@@ -498,23 +512,6 @@ int xenbus_write(struct xenbus_transaction t,
 }
 EXPORT_SYMBOL_GPL(xenbus_write);
 
-/* Create a new directory. */
-int xenbus_mkdir(struct xenbus_transaction t,
-		 const char *dir, const char *node)
-{
-	char *path;
-	int ret;
-
-	path = join(dir, node);
-	if (IS_ERR(path))
-		return PTR_ERR(path);
-
-	ret = xs_error(xs_single(t, XS_MKDIR, path, NULL));
-	kfree(path);
-	return ret;
-}
-EXPORT_SYMBOL_GPL(xenbus_mkdir);
-
 /* Destroy a file or directory (directories must be empty). */
 int xenbus_rm(struct xenbus_transaction t, const char *dir, const char *node)
 {
@@ -549,18 +546,12 @@ int xenbus_transaction_start(struct xenbus_transaction *t)
 EXPORT_SYMBOL_GPL(xenbus_transaction_start);
 
 /* End a transaction.
- * If abandon is true, transaction is discarded instead of committed.
+ * If abort is true, transaction is discarded instead of committed.
  */
-int xenbus_transaction_end(struct xenbus_transaction t, int abort)
+int xenbus_transaction_end(struct xenbus_transaction t, bool abort)
 {
-	char abortstr[2];
-
-	if (abort)
-		strcpy(abortstr, "F");
-	else
-		strcpy(abortstr, "T");
-
-	return xs_error(xs_single(t, XS_TRANSACTION_END, abortstr, NULL));
+	return xs_error(xs_single(t, XS_TRANSACTION_END, abort ? "F" : "T",
+				  NULL));
 }
 EXPORT_SYMBOL_GPL(xenbus_transaction_end);
 
@@ -721,26 +712,6 @@ int xs_watch_msg(struct xs_watch_event *event)
 	return 0;
 }
 
-/*
- * Certain older XenBus toolstack cannot handle reading values that are
- * not populated. Some Xen 3.4 installation are incapable of doing this
- * so if we are running on anything older than 4 do not attempt to read
- * control/platform-feature-xs_reset_watches.
- */
-static bool xen_strict_xenbus_quirk(void)
-{
-#ifdef CONFIG_X86
-	uint32_t eax, ebx, ecx, edx, base;
-
-	base = xen_cpuid_base();
-	cpuid(base + 1, &eax, &ebx, &ecx, &edx);
-
-	if ((eax >> 16) < 4)
-		return true;
-#endif
-	return false;
-
-}
 static void xs_reset_watches(void)
 {
 	int err;
@@ -748,9 +719,6 @@ static void xs_reset_watches(void)
 	if (!xen_hvm_domain() || xen_initial_domain())
 		return;
 
-	if (xen_strict_xenbus_quirk())
-		return;
-
 	if (!xenbus_read_unsigned("control",
 				  "platform-feature-xs_reset_watches", 0))
 		return;