[PATCH 05/21] Drivers: hv: vss: process deferred messages when we complete the transaction

From: K. Y. Srinivasan
Date: Sat Apr 11 2015 - 19:51:59 EST


From: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>

In theory, the host is not supposed to issue any requests before be reply to
the previous one. In KVP we, however, support the following scenarios:
1) A message was received before userspace daemon registered;
2) A message was received while the previous one is still being processed.
In VSS we support only the former. Add support for the later, use
hv_poll_channel() to do the job.

Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
Tested-by: Alex Ng <alexng@xxxxxxxxxxxxx>
Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
---
drivers/hv/hv_snapshot.c | 14 +++++++++-----
1 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/hv/hv_snapshot.c b/drivers/hv/hv_snapshot.c
index c1a3604..4bb9b1c 100644
--- a/drivers/hv/hv_snapshot.c
+++ b/drivers/hv/hv_snapshot.c
@@ -47,6 +47,7 @@ static struct {
struct vmbus_channel *recv_channel; /* chn we got the request */
u64 recv_req_id; /* request ID. */
struct hv_vss_msg *msg; /* current message */
+ void *vss_context; /* for the channel callback */
} vss_transaction;


@@ -73,6 +74,9 @@ static void vss_timeout_func(struct work_struct *dummy)
*/
pr_warn("VSS: timeout waiting for daemon to reply\n");
vss_respond_to_host(HV_E_FAIL);
+
+ hv_poll_channel(vss_transaction.vss_context,
+ hv_vss_onchannelcallback);
}

static void
@@ -85,13 +89,12 @@ vss_cn_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
if (vss_msg->vss_hdr.operation == VSS_OP_REGISTER) {
pr_info("VSS daemon registered\n");
vss_transaction.active = false;
- if (vss_transaction.recv_channel != NULL)
- hv_vss_onchannelcallback(vss_transaction.recv_channel);
- return;
-
}
if (cancel_delayed_work_sync(&vss_timeout_work))
vss_respond_to_host(vss_msg->error);
+
+ hv_poll_channel(vss_transaction.vss_context,
+ hv_vss_onchannelcallback);
}


@@ -198,9 +201,10 @@ void hv_vss_onchannelcallback(void *context)
* We will defer processing this callback once
* the current transaction is complete.
*/
- vss_transaction.recv_channel = channel;
+ vss_transaction.vss_context = context;
return;
}
+ vss_transaction.vss_context = NULL;

vmbus_recvpacket(channel, recv_buffer, PAGE_SIZE * 2, &recvlen,
&requestid);
--
1.7.4.1

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