Drivers: hv: vmbus: Enable explicit signaling policy for NIC channels

For synthetic NIC channels, enable explicit signaling policy as netvsc wants to
explicitly control when the host is to be signaled.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 12 insertions, 3 deletions

diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c
index fe586bf74e17..e3edcaee7ab3 100644
--- a/drivers/hv/ring_buffer.c
+++ b/drivers/hv/ring_buffer.c
@@ -66,12 +66,20 @@ u32 hv_end_read(struct hv_ring_buffer_info *rbi)
  *         arrived.
  */
 
-static bool hv_need_to_signal(u32 old_write, struct hv_ring_buffer_info *rbi)
+static bool hv_need_to_signal(u32 old_write, struct hv_ring_buffer_info *rbi,
+                              enum hv_signal_policy policy)
 {
         virt_mb();
         if (READ_ONCE(rbi->ring_buffer->interrupt_mask))
                 return false;
 
+        /*
+         * When the client wants to control signaling,
+         * we only honour the host interrupt mask.
+         */
+        if (policy == HV_SIGNAL_POLICY_EXPLICIT)
+                return true;
+
         /* check interrupt_mask before read_index */
         virt_rmb();
         /*
@@ -264,7 +272,8 @@ void hv_ringbuffer_cleanup(struct hv_ring_buffer_info *ring_info)
 
 /* Write to the ring buffer. */
 int hv_ringbuffer_write(struct hv_ring_buffer_info *outring_info,
-                    struct kvec *kv_list, u32 kv_count, bool *signal, bool lock)
+                    struct kvec *kv_list, u32 kv_count, bool *signal, bool lock,
+                    enum hv_signal_policy policy)
 {
         int i = 0;
         u32 bytes_avail_towrite;
@@ -326,7 +335,7 @@ int hv_ringbuffer_write(struct hv_ring_buffer_info *outring_info,
         if (lock)
                 spin_unlock_irqrestore(&outring_info->ring_lock, flags);
 
-        *signal = hv_need_to_signal(old_write, outring_info);
+        *signal = hv_need_to_signal(old_write, outring_info, policy);
         return 0;
 }