hv: make "monitor_pages" a "real" pointer array

monitor_pages was a void pointer, containing an unknown number of arrays that
we just "knew" were a child and parent array of a specific size.  Instead of
that implicit knowledge, let's make them a real pointer, allowing us to have
type safety, and a semblance of sane addressing schemes.

Tested-by: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

3 files changed, 15 insertions, 18 deletions

diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
index dde30b48c56c..04bf06560085 100644
--- a/drivers/hv/channel.c
+++ b/drivers/hv/channel.c
@@ -47,8 +47,8 @@ static void vmbus_setevent(struct vmbus_channel *channel)
                         (unsigned long *) vmbus_connection.send_int_page +
                         (channel->offermsg.child_relid >> 5));
 
-                monitorpage = vmbus_connection.monitor_pages;
-                monitorpage++; /* Get the child to parent monitor page */
+                /* Get the child to parent monitor page */
+                monitorpage = vmbus_connection.monitor_pages[1];
 
                 sync_set_bit(channel->monitor_bit,
                         (unsigned long *)&monitorpage->trigger_group
@@ -69,8 +69,7 @@ void vmbus_get_debug_info(struct vmbus_channel *channel,
         u8 monitor_group = (u8)channel->offermsg.monitorid / 32;
         u8 monitor_offset = (u8)channel->offermsg.monitorid % 32;
 
-        monitorpage = (struct hv_monitor_page *)vmbus_connection.monitor_pages;
-
+        monitorpage = vmbus_connection.monitor_pages[0];
         debuginfo->servermonitor_pending =
                         monitorpage->trigger_group[monitor_group].pending;
         debuginfo->servermonitor_latency =
@@ -79,8 +78,7 @@ void vmbus_get_debug_info(struct vmbus_channel *channel,
                         monitorpage->parameter[monitor_group]
                                         [monitor_offset].connectionid.u.id;
 
-        monitorpage++;
-
+        monitorpage = vmbus_connection.monitor_pages[1];
         debuginfo->clientmonitor_pending =
                         monitorpage->trigger_group[monitor_group].pending;
         debuginfo->clientmonitor_latency =
diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
index 8f4743ab5fb2..4faea979975e 100644
--- a/drivers/hv/connection.c
+++ b/drivers/hv/connection.c
@@ -76,10 +76,8 @@ static int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo,
         msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT;
         msg->vmbus_version_requested = version;
         msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
-        msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages);
-        msg->monitor_page2 = virt_to_phys(
-                        (void *)((unsigned long)vmbus_connection.monitor_pages +
-                                 PAGE_SIZE));
+        msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages[0]);
+        msg->monitor_page2 = virt_to_phys(vmbus_connection.monitor_pages[1]);
 
         /*
          * Add to list before we send the request since we may
@@ -169,9 +167,10 @@ int vmbus_connect(void)
          * Setup the monitor notification facility. The 1st page for
          * parent->child and the 2nd page for child->parent
          */
-        vmbus_connection.monitor_pages =
-        (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 1);
-        if (vmbus_connection.monitor_pages == NULL) {
+        vmbus_connection.monitor_pages[0] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0);
+        vmbus_connection.monitor_pages[1] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0);
+        if ((vmbus_connection.monitor_pages[0] == NULL) ||
+            (vmbus_connection.monitor_pages[1] == NULL)) {
                 ret = -ENOMEM;
                 goto cleanup;
         }
@@ -229,10 +228,10 @@ cleanup:
                 vmbus_connection.int_page = NULL;
         }
 
-        if (vmbus_connection.monitor_pages) {
-                free_pages((unsigned long)vmbus_connection.monitor_pages, 1);
-                vmbus_connection.monitor_pages = NULL;
-        }
+        free_pages((unsigned long)vmbus_connection.monitor_pages[0], 1);
+        free_pages((unsigned long)vmbus_connection.monitor_pages[1], 1);
+        vmbus_connection.monitor_pages[0] = NULL;
+        vmbus_connection.monitor_pages[1] = NULL;
 
         kfree(msginfo);
 
diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h
index d84918fe19ab..d58c22ffb29a 100644
--- a/drivers/hv/hyperv_vmbus.h
+++ b/drivers/hv/hyperv_vmbus.h
@@ -612,7 +612,7 @@ struct vmbus_connection {
          * 2 pages - 1st page for parent->child notification and 2nd
          * is child->parent notification
          */
-        void *monitor_pages;
+        struct hv_monitor_page *monitor_pages[2];
         struct list_head chn_msg_list;
         spinlock_t channelmsg_lock;