[Cluster-devel] [RFC PATCH dlm/next 10/16] fs: dlm: add functionality to retransmit a message

[Alexander Aring <aahringo@redhat.com>]

This patch introduces a irqsafe retransmit functionality for a lowcomms
message handle. It's just allocates a new buffer and transmit it again.
To avoid another connection look some refactor was done to make a new
buffer allocation with a preexisting connection pointer.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
---
 fs/dlm/lowcomms.c | 54 +++++++++++++++++++++++++++++++++++------------
 fs/dlm/lowcomms.h |  1 +
 2 files changed, 41 insertions(+), 14 deletions(-)

diff --git a/fs/dlm/lowcomms.c b/fs/dlm/lowcomms.c
index 3c133cd2ff22..0ef1a1ffd301 100644
--- a/fs/dlm/lowcomms.c
+++ b/fs/dlm/lowcomms.c
@@ -1428,24 +1428,14 @@ static struct writequeue_entry *new_wq_entry(struct connection *con, int len,
 	return e;
 };
 
-void *dlm_lowcomms_new_buffer(int nodeid, int len, gfp_t allocation, char **ppc,
-			      void (*cb)(void *buf, void *priv), void *priv)
+static void *dlm_lowcomms_new_buffer_con(struct connection *con, int len,
+					 gfp_t allocation, char **ppc,
+					 void (*cb)(void *buf, void *priv),
+					 void *priv)
 {
 	struct writequeue_entry *e;
-	struct connection *con;
 	struct dlm_msg *msg;
 
-	if (len > LOWCOMMS_MAX_TX_BUFFER_LEN ||
-	    len < sizeof(struct dlm_header)) {
-		BUILD_BUG_ON(PAGE_SIZE < LOWCOMMS_MAX_TX_BUFFER_LEN);
-		log_print("failed to allocate a buffer of size %d", len);
-		return NULL;
-	}
-
-	con = nodeid2con(nodeid, allocation);
-	if (!con)
-		return NULL;
-
 	msg = kzalloc(sizeof(*msg), allocation);
 	if (!msg)
 		return NULL;
@@ -1465,6 +1455,25 @@ void *dlm_lowcomms_new_buffer(int nodeid, int len, gfp_t allocation, char **ppc,
 	return msg;
 }
 
+void *dlm_lowcomms_new_buffer(int nodeid, int len, gfp_t allocation, char **ppc,
+			      void (*cb)(void *buf, void *priv), void *priv)
+{
+	struct connection *con;
+
+	if (len > LOWCOMMS_MAX_TX_BUFFER_LEN ||
+	    len < sizeof(struct dlm_header)) {
+		BUILD_BUG_ON(PAGE_SIZE < LOWCOMMS_MAX_TX_BUFFER_LEN);
+		log_print("failed to allocate a buffer of size %d", len);
+		return NULL;
+	}
+
+	con = nodeid2con(nodeid, allocation);
+	if (!con)
+		return NULL;
+
+	return dlm_lowcomms_new_buffer_con(con, len, GFP_ATOMIC, ppc, cb, priv);
+}
+
 void dlm_lowcomms_commit_buffer(void *mh)
 {
 	struct dlm_msg *msg = mh;
@@ -1505,6 +1514,23 @@ void dlm_lowcomms_get_buffer(void *mh)
 	kref_get(&msg->ref);
 }
 
+/* irqsafe */
+void dlm_lowcomms_resend_buffer(void *mh)
+{
+	struct dlm_msg *msg = mh;
+	void *mh_new;
+	char *ppc;
+
+	mh_new = dlm_lowcomms_new_buffer_con(msg->entry->con, msg->len, GFP_ATOMIC,
+					     &ppc, NULL, NULL);
+	if (!mh_new)
+		return;
+
+	memcpy(ppc, msg->ppc, msg->len);
+	dlm_lowcomms_commit_buffer(mh_new);
+	dlm_lowcomms_put_buffer(mh_new);
+}
+
 /* Send a message */
 static void send_to_sock(struct connection *con)
 {
diff --git a/fs/dlm/lowcomms.h b/fs/dlm/lowcomms.h
index 6417c5fca215..30924b6f03e1 100644
--- a/fs/dlm/lowcomms.h
+++ b/fs/dlm/lowcomms.h
@@ -28,6 +28,7 @@ int dlm_lowcomms_connect_node(int nodeid);
 int dlm_lowcomms_addr(int nodeid, struct sockaddr_storage *addr, int len);
 void dlm_lowcomms_put_buffer(void *mh);
 void dlm_lowcomms_get_buffer(void *mh);
+void dlm_lowcomms_resend_buffer(void *mh);
 
 #endif				/* __LOWCOMMS_DOT_H__ */
 
-- 
2.26.2