[PATCH V2 10/13] Drivers: hv: vmbus: add a per-channel rescind callback

[K. Y. Srinivasan]

From: Dexuan Cui <de...@microsoft.com>

This will be used by the coming hv_sock driver.

Signed-off-by: Dexuan Cui <de...@microsoft.com>
Signed-off-by: K. Y. Srinivasan <k...@microsoft.com>
---
 drivers/hv/channel_mgmt.c |   11 +++++++++++
 include/linux/hyperv.h    |    9 +++++++++
 2 files changed, 20 insertions(+), 0 deletions(-)

diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index 60ca25b..76864c9 100644
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -741,6 +741,10 @@ static void vmbus_onoffer_rescind(struct 
vmbus_channel_message_header *hdr)
        spin_unlock_irqrestore(&channel->lock, flags);
 
        if (channel->device_obj) {
+               if (channel->chn_rescind_callback) {
+                       channel->chn_rescind_callback(channel);
+                       return;
+               }
                /*
                 * We will have to unregister this device from the
                 * driver core.
@@ -1110,3 +1114,10 @@ bool vmbus_are_subchannels_present(struct vmbus_channel 
*primary)
        return ret;
 }
 EXPORT_SYMBOL_GPL(vmbus_are_subchannels_present);
+
+void vmbus_set_chn_rescind_callback(struct vmbus_channel *channel,
+               void (*chn_rescind_cb)(struct vmbus_channel *))
+{
+       channel->chn_rescind_callback = chn_rescind_cb;
+}
+EXPORT_SYMBOL_GPL(vmbus_set_chn_rescind_callback);
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index f636f91..2e54e34 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -766,6 +766,12 @@ struct vmbus_channel {
        void (*sc_creation_callback)(struct vmbus_channel *new_sc);
 
        /*
+        * Channel rescind callback. Some channels (the hvsock ones), need to
+        * register a callback which is invoked in vmbus_onoffer_rescind().
+        */
+       void (*chn_rescind_callback)(struct vmbus_channel *channel);
+
+       /*
         * The spinlock to protect the structure. It is being used to protect
         * test-and-set access to various attributes of the structure as well
         * as all sc_list operations.
@@ -851,6 +857,9 @@ int vmbus_request_offers(void);
 void vmbus_set_sc_create_callback(struct vmbus_channel *primary_channel,
                        void (*sc_cr_cb)(struct vmbus_channel *new_sc));
 
+void vmbus_set_chn_rescind_callback(struct vmbus_channel *channel,
+               void (*chn_rescind_cb)(struct vmbus_channel *));
+
 /*
  * Retrieve the (sub) channel on which to send an outgoing request.
  * When a primary channel has multiple sub-channels, we choose a
-- 
1.7.4.1