[Devel] [PATCH VZ10 v3 1/2] ve/sunrpc: Refactor {rpc, write}_kill_tasks

[Vladimir Riabchun]

1. Rename rpc_kill_tasks to rpc_set_kill_net and add value parameter,
   so that function can now both enable and disable RPC traffic.
2. Move sn->kill_tasks check to rpc_set_kill_net so that
   file write function is only responsible for parsing and calling,
   not for logic checks.

This will allow later usage of rpc_set_kill_net without
kill_tasks check duplication.

https://virtuozzo.atlassian.net/browse/VSTOR-126316

Feature: improve kill-tasks
Signed-off-by: Vladimir Riabchun <vladimir.riabchun at virtuozzo.com>
---
v2 -> v3:
 - Rename rpc_kill_tasks and add a new parameter
 - Support clearing sn->kill_tasks in rpc_set_kill_net

 net/sunrpc/clnt.c | 35 ++++++++++++++++++++---------------
 1 file changed, 20 insertions(+), 15 deletions(-)

diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 266cf0fbbad5..0b7f69eb910d 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -3406,15 +3406,32 @@ rpc_clnt_swap_deactivate(struct rpc_clnt *clnt)
 EXPORT_SYMBOL_GPL(rpc_clnt_swap_deactivate);
 #endif /* CONFIG_SUNRPC_SWAP */
 
-static void rpc_kill_tasks(struct net *net)
+static void rpc_set_kill_net(struct net *net, bool new_value)
 {
 	struct rpc_clnt *clnt;
 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
+	if (sn->kill_tasks == new_value)
+		return;
+
+	sn->kill_tasks = new_value;
+	if (!new_value) {
+		pr_info_ratelimited(
+			"task (%s:%d) cleared RPC kill_tasks in net [%u]\n",
+			current->comm, current->pid, net->ns.inum);
+		return;
+	}
 
 	spin_lock(&sn->rpc_client_lock);
 	list_for_each_entry(clnt, &sn->all_clients, cl_clients)
 		rpc_killall_tasks(clnt);
 	spin_unlock(&sn->rpc_client_lock);
+
+	pr_info_ratelimited("task (%s:%d) killed RPC in net:[%u]%s\n",
+			    current->comm, current->pid, net->ns.inum,
+#ifdef CONFIG_VE
+			    net->owner_ve == &ve0 ? "(host)" :
+#endif
+			    "");
 }
 
 static ssize_t write_kill_tasks(struct file *file, const char __user *buf,
@@ -3422,7 +3439,6 @@ static ssize_t write_kill_tasks(struct file *file, const char __user *buf,
 {
 	struct net *net = pde_data(file->f_path.dentry->d_inode);
 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
-	bool prev_kill_tasks = sn->kill_tasks;
 	char tbuf[20];
 	unsigned long kill_tasks;
 	int res;
@@ -3437,19 +3453,8 @@ static ssize_t write_kill_tasks(struct file *file, const char __user *buf,
 	if (res)
 		return res;
 
-	sn->kill_tasks = !!kill_tasks;
-
-	/* Kill pending tasks */
-	if (sn->kill_tasks && !prev_kill_tasks) {
-		rpc_kill_tasks(net);
-		pr_info_ratelimited(
-			"kill-tasks: by task (%s:%d) in net:[%u]%s\n",
-			current->comm, current->pid, net->ns.inum,
-#ifdef CONFIG_VE
-			net->owner_ve == &ve0 ? "(host)" :
-#endif
-			"");
-	}
+	/* Kill pending tasks or forget about previous murder */
+	rpc_set_kill_net(net, kill_tasks);
 
 	return count;
 }
-- 
2.47.1