1 files changed, 25 insertions, 28 deletions

diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index cd184bdca58f..42fe43fb0c80 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -696,7 +696,7 @@ enum vmbus_device_type {
         HV_FCOPY,
         HV_BACKUP,
         HV_DM,
-        HV_UNKOWN,
+        HV_UNKNOWN,
 };
 
 struct vmbus_device {
@@ -1119,6 +1119,12 @@ struct hv_driver {
 
         struct device_driver driver;
 
+        /* dynamic device GUID's */
+        struct  {
+                spinlock_t lock;
+                struct list_head list;
+        } dynids;
+
         int (*probe)(struct hv_device *, const struct hv_vmbus_device_id *);
         int (*remove)(struct hv_device *);
         void (*shutdown)(struct hv_device *);
@@ -1447,6 +1453,7 @@ void hv_event_tasklet_enable(struct vmbus_channel *channel);
 
 void hv_process_channel_removal(struct vmbus_channel *channel, u32 relid);
 
+void vmbus_setevent(struct vmbus_channel *channel);
 /*
  * Negotiated version with the Host.
  */
@@ -1479,10 +1486,11 @@ hv_get_ring_buffer(struct hv_ring_buffer_info *ring_info)
  *    there is room for the producer to send the pending packet.
  */
 
-static inline  bool hv_need_to_signal_on_read(struct hv_ring_buffer_info *rbi)
+static inline  void hv_signal_on_read(struct vmbus_channel *channel)
 {
         u32 cur_write_sz;
         u32 pending_sz;
+        struct hv_ring_buffer_info *rbi = &channel->inbound;
 
         /*
          * Issue a full memory barrier before making the signaling decision.
@@ -1500,14 +1508,14 @@ static inline  bool hv_need_to_signal_on_read(struct hv_ring_buffer_info *rbi)
         pending_sz = READ_ONCE(rbi->ring_buffer->pending_send_sz);
         /* If the other end is not blocked on write don't bother. */
         if (pending_sz == 0)
-                return false;
+                return;
 
         cur_write_sz = hv_get_bytes_to_write(rbi);
 
         if (cur_write_sz >= pending_sz)
-                return true;
+                vmbus_setevent(channel);
 
-        return false;
+        return;
 }
 
 /*
@@ -1519,31 +1527,23 @@ static inline struct vmpacket_descriptor *
 get_next_pkt_raw(struct vmbus_channel *channel)
 {
         struct hv_ring_buffer_info *ring_info = &channel->inbound;
-        u32 read_loc = ring_info->priv_read_index;
+        u32 priv_read_loc = ring_info->priv_read_index;
         void *ring_buffer = hv_get_ring_buffer(ring_info);
-        struct vmpacket_descriptor *cur_desc;
-        u32 packetlen;
         u32 dsize = ring_info->ring_datasize;
-        u32 delta = read_loc - ring_info->ring_buffer->read_index;
+        /*
+         * delta is the difference between what is available to read and
+         * what was already consumed in place. We commit read index after
+         * the whole batch is processed.
+         */
+        u32 delta = priv_read_loc >= ring_info->ring_buffer->read_index ?
+                priv_read_loc - ring_info->ring_buffer->read_index :
+                (dsize - ring_info->ring_buffer->read_index) + priv_read_loc;
         u32 bytes_avail_toread = (hv_get_bytes_to_read(ring_info) - delta);
 
         if (bytes_avail_toread < sizeof(struct vmpacket_descriptor))
                 return NULL;
 
-        if ((read_loc + sizeof(*cur_desc)) > dsize)
-                return NULL;
-
-        cur_desc = ring_buffer + read_loc;
-        packetlen = cur_desc->len8 << 3;
-
-        /*
-         * If the packet under consideration is wrapping around,
-         * return failure.
-         */
-        if ((read_loc + packetlen + VMBUS_PKT_TRAILER) > (dsize - 1))
-                return NULL;
-
-        return cur_desc;
+        return ring_buffer + priv_read_loc;
 }
 
 /*
@@ -1555,16 +1555,14 @@ static inline void put_pkt_raw(struct vmbus_channel *channel,
                                 struct vmpacket_descriptor *desc)
 {
         struct hv_ring_buffer_info *ring_info = &channel->inbound;
-        u32 read_loc = ring_info->priv_read_index;
         u32 packetlen = desc->len8 << 3;
         u32 dsize = ring_info->ring_datasize;
 
-        if ((read_loc + packetlen + VMBUS_PKT_TRAILER) > dsize)
-                BUG();
         /*
          * Include the packet trailer.
          */
         ring_info->priv_read_index += packetlen + VMBUS_PKT_TRAILER;
+        ring_info->priv_read_index %= dsize;
 }
 
 /*
@@ -1589,8 +1587,7 @@ static inline void commit_rd_index(struct vmbus_channel *channel)
         virt_rmb();
         ring_info->ring_buffer->read_index = ring_info->priv_read_index;
 
-        if (hv_need_to_signal_on_read(ring_info))
-                vmbus_set_event(channel);
+        hv_signal_on_read(channel);
 }