sunrpc: introduce lttng_get_clid helper

Introduce the lttng_get_clid helper to always check for NULL pointer
when getting the client id. While not always strictly needed depending
on the tracepoint callsite, prefer robustness of instrumentation and
always check for NULL rather than play whack-a-mole.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

diff --git a/instrumentation/events/lttng-module/rpc.h b/instrumentation/events/lttng-module/rpc.h
index 4dd9cabf56ab8e508f1ea59c53666f263bc94be8..3a866a78b997d727b13932c33c24546580b6a219 100644 (file)
--- a/instrumentation/events/lttng-module/rpc.h
+++ b/instrumentation/events/lttng-module/rpc.h
@@ -8,6 +8,29 @@
 #include <linux/sunrpc/sched.h>
 #include <linux/sunrpc/clnt.h>
 
+#ifndef ONCE_LTTNG_RPC_H
+#define ONCE_LTTNG_RPC_H
+
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,12,0))
+static inline
+int lttng_get_clid(const struct rpc_task *task)
+{
+       struct rpc_clnt *tk_client;
+
+       tk_client = task->tk_client;
+       if (!tk_client)
+               return -1;
+       /*
+        * The cl_clid field is always initialized to positive signed
+        * integers. Negative signed integer values are treated as
+        * errors.
+        */
+       return (int) tk_client->cl_clid;
+}
+#endif /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,12,0)) */
+
+#endif /* ONCE_LTTNG_RPC_H */
+
 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(5,0,0))
 LTTNG_TRACEPOINT_EVENT_CLASS(rpc_task_status,
 
@@ -17,7 +40,7 @@ LTTNG_TRACEPOINT_EVENT_CLASS(rpc_task_status,
 
        TP_FIELDS(
                ctf_integer(unsigned int, task_id, task->tk_pid)
-               ctf_integer(int, client_id, task->tk_client->cl_clid)
+               ctf_integer(int, client_id, lttng_get_clid(task))
                ctf_integer(int, status, task->tk_status)
        )
 )
@@ -42,7 +65,7 @@ LTTNG_TRACEPOINT_EVENT_CLASS(rpc_task_status,
 
        TP_FIELDS(
                ctf_integer(unsigned int, task_id, task->tk_pid)
-               ctf_integer(int, client_id, task->tk_client->cl_clid)
+               ctf_integer(int, client_id, lttng_get_clid(task))
                ctf_integer(int, status, task->tk_status)
        )
 )
@@ -99,7 +122,7 @@ LTTNG_TRACEPOINT_EVENT(rpc_connect_status,
 
        TP_FIELDS(
                ctf_integer(unsigned int, task_id, task->tk_pid)
-               ctf_integer(int, client_id, task->tk_client->cl_clid)
+               ctf_integer(int, client_id, lttng_get_clid(task))
                ctf_integer(int, status, task->tk_status)
        )
 )
@@ -111,7 +134,7 @@ LTTNG_TRACEPOINT_EVENT(rpc_connect_status,
 
        TP_FIELDS(
                ctf_integer(unsigned int, task_id, task->tk_pid)
-               ctf_integer(int, client_id, task->tk_client->cl_clid)
+               ctf_integer(int, client_id, lttng_get_clid(task))
                ctf_integer(int, status, status)
        )
 )
@@ -138,8 +161,7 @@ LTTNG_TRACEPOINT_EVENT_CLASS(rpc_task_running,
 
        TP_FIELDS(
                ctf_integer(unsigned int, task_id, task->tk_pid)
-               ctf_integer(int, client_id, task->tk_client ?
-                       task->tk_client->cl_clid : -1)
+               ctf_integer(int, client_id, lttng_get_clid(task))
                ctf_integer_hex(const void *, action, action)
                ctf_integer(unsigned long, runstate, task->tk_runstate)
                ctf_integer(int, status, task->tk_status)
@@ -176,8 +198,7 @@ LTTNG_TRACEPOINT_EVENT_CLASS(rpc_task_queued,
 
        TP_FIELDS(
                ctf_integer(unsigned int, task_id, task->tk_pid)
-               ctf_integer(int, client_id, task->tk_client ?
-                               task->tk_client->cl_clid : -1)
+               ctf_integer(int, client_id, lttng_get_clid(task))
                ctf_integer(unsigned long, timeout, task->tk_timeout)
                ctf_integer(unsigned long, runstate, task->tk_runstate)
                ctf_integer(int, status, task->tk_status)
@@ -209,8 +230,7 @@ LTTNG_TRACEPOINT_EVENT_CLASS(rpc_task_running,
 
        TP_FIELDS(
                ctf_integer(unsigned int, task_id, task->tk_pid)
-               ctf_integer(int, client_id, task->tk_client ?
-                       task->tk_client->cl_clid : -1)
+               ctf_integer(int, client_id, lttng_get_clid(task))
                ctf_integer_hex(const void *, action, action)
                ctf_integer(unsigned long, runstate, task->tk_runstate)
                ctf_integer(int, status, task->tk_status)
@@ -247,8 +267,7 @@ LTTNG_TRACEPOINT_EVENT_CLASS(rpc_task_queued,
 
        TP_FIELDS(
                ctf_integer(unsigned int, task_id, task->tk_pid)
-               ctf_integer(int, client_id, task->tk_client ?
-                       task->tk_client->cl_clid : -1)
+               ctf_integer(int, client_id, lttng_get_clid(task))
                ctf_integer(unsigned long, timeout, task->tk_timeout)
                ctf_integer(unsigned long, runstate, task->tk_runstate)
                ctf_integer(int, status, task->tk_status)