[[PATCH v1] 25/37] [CIFS] SMBD: Support SMBD idle connection timer

[Long Li]

From: Long Li <lon...@microsoft.com>

This is part of the keep alive protocol. Each peer maintains a timer, and will 
send a message to peer when it expires.

Signed-off-by: Long Li <lon...@microsoft.com>
---
 fs/cifs/cifsrdma.c | 25 +++++++++++++++++++++++++
 fs/cifs/cifsrdma.h |  6 ++++--
 2 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/fs/cifs/cifsrdma.c b/fs/cifs/cifsrdma.c
index e275834..523c80f 100644
--- a/fs/cifs/cifsrdma.c
+++ b/fs/cifs/cifsrdma.c
@@ -89,6 +89,7 @@ static int send_credit_target = 512;
 static int max_send_size = 8192;
 static int max_fragmented_recv_size = 1024*1024;
 static int max_receive_size = 8192;
+static int keep_alive_interval = 120;
 
 // maximum number of SGEs in a RDMA I/O
 static int max_send_sge = 16;
@@ -1200,6 +1201,25 @@ static void destroy_receive_buffers(struct 
cifs_rdma_info *info)
                mempool_free(response, info->response_mempool);
 }
 
+// Implement idle connection timer [MS-SMBD] 3.1.6.2
+static void idle_connection_timer(struct work_struct *work)
+{
+       struct cifs_rdma_info *info = container_of(
+                                       work, struct cifs_rdma_info,
+                                       idle_timer_work.work);
+
+       if (info->keep_alive_requested != KEEP_ALIVE_NONE)
+               log_keep_alive("error status info->keep_alive_requested=%d\n",
+                               info->keep_alive_requested);
+
+       log_keep_alive("about to send an empty idle message\n");
+       cifs_rdma_post_send_empty(info);
+
+       // setup the next idle timeout work
+       schedule_delayed_work(&info->idle_timer_work,
+                               info->keep_alive_interval*HZ);
+}
+
 int cifs_reconnect_rdma_session(struct TCP_Server_Info *server)
 {
        log_rdma_event("reconnecting rdma session\n");
@@ -1262,6 +1282,7 @@ struct cifs_rdma_info* cifs_create_rdma_session(
        info->max_send_size = max_send_size;
        info->max_fragmented_recv_size = max_fragmented_recv_size;
        info->max_receive_size = max_receive_size;
+       info->keep_alive_interval = keep_alive_interval;
 
        max_send_sge = min_t(int, max_send_sge,
                info->id->device->attrs.max_sge);
@@ -1348,6 +1369,10 @@ struct cifs_rdma_info* cifs_create_rdma_session(
        init_waitqueue_head(&info->wait_send_queue);
        init_waitqueue_head(&info->wait_reassembly_queue);
 
+       INIT_DELAYED_WORK(&info->idle_timer_work, idle_connection_timer);
+       schedule_delayed_work(&info->idle_timer_work,
+               info->keep_alive_interval*HZ);
+
        init_waitqueue_head(&info->wait_send_pending);
        atomic_set(&info->send_pending, 0);
 
diff --git a/fs/cifs/cifsrdma.h b/fs/cifs/cifsrdma.h
index 62d0bb8..dd497ce 100644
--- a/fs/cifs/cifsrdma.h
+++ b/fs/cifs/cifsrdma.h
@@ -73,6 +73,7 @@ struct cifs_rdma_info {
        int max_fragmented_recv_size;
        int max_fragmented_send_size;
        int max_receive_size;
+       int keep_alive_interval;
        int max_readwrite_size;
        enum keep_alive_status keep_alive_requested;
        int protocol;
@@ -101,12 +102,13 @@ struct cifs_rdma_info {
 
        wait_queue_head_t wait_send_queue;
 
+       bool full_packet_received;
+       struct delayed_work idle_timer_work;;
+
        // request pool for RDMA send
        struct kmem_cache *request_cache;
        mempool_t *request_mempool;
 
-       bool full_packet_received;
-
        // response pool for RDMA receive
        struct kmem_cache *response_cache;
        mempool_t *response_mempool;
-- 
2.7.4