From fbb26e17a4c026f05a497fc5d584516bad3b6950 Mon Sep 17 00:00:00 2001
From: David Smith <dsmith@redhat.com>
Date: Wed, 6 Dec 2017 14:37:42 -0600
Subject: [PATCH] Fix PR22551 by updating the use of timers for the 4.15
 kernel.

* runtime/linux/timer_compatibility.h: New file.
* runtime/time.c: Update timer callback function parameter type. Update
  timer initialization.
* runtime/transport/relay_v2.c: Ditto.
* runtime/transport/transport.c: Ditto.
* tapset-timers.cxx (timer_derived_probe_group::emit_module_decls):
  Ditto. Handle old and new timer callback interface.
* runtime/linux/runtime.h: Include timer_compatibility.h instead of timer.h.
* tapset/linux/scsi.stp: Ditto.

Upstream-Status: Backport
Signed-off-by: Victor Kamensky <kamensky@cisco.com>

---
 runtime/linux/runtime.h             |  2 +-
 runtime/linux/timer_compatibility.h | 76 +++++++++++++++++++++++++++++++++++++
 runtime/time.c                      |  7 ++--
 runtime/transport/relay_v2.c        |  8 ++--
 runtime/transport/transport.c       | 13 +++----
 tapset-timers.cxx                   | 14 +++++--
 tapset/linux/scsi.stp               |  2 +-
 7 files changed, 100 insertions(+), 22 deletions(-)
 create mode 100644 runtime/linux/timer_compatibility.h

diff --git a/runtime/linux/runtime.h b/runtime/linux/runtime.h
index 9c585a2..df9b74c 100644
--- a/runtime/linux/runtime.h
+++ b/runtime/linux/runtime.h
@@ -34,7 +34,7 @@
 #include <linux/compat.h>
 #include <linux/sched.h>
 #include <linux/mm.h>
-#include <linux/timer.h>
+#include "timer_compatibility.h"
 #include <linux/delay.h>
 #include <linux/profile.h>
 #include <linux/rcupdate.h>
diff --git a/runtime/linux/timer_compatibility.h b/runtime/linux/timer_compatibility.h
new file mode 100644
index 0000000..ac03de9
--- /dev/null
+++ b/runtime/linux/timer_compatibility.h
@@ -0,0 +1,76 @@
+/*
+ * linux/timer.h compatibility defines and inlines
+ * Copyright (C) 2017 Red Hat Inc.
+ *
+ * This file is part of systemtap, and is free software.  You can
+ * redistribute it and/or modify it under the terms of the GNU General
+ * Public License (GPL); either version 2, or (at your option) any
+ * later version.
+ */
+
+#ifndef _TIMER_COMPATIBILITY_H_
+#define _TIMER_COMPATIBILITY_H_
+
+#include <linux/timer.h>
+
+/*
+ * Starting with the 4.15 kernel, the timer interface
+ * changed. Originally, you'd do something like:
+ *
+ *   static void timer_func(unsigned long val);
+ *
+ *   init_timer(&timer);
+ *   timer.expires = jiffies + STP_RELAY_TIMER_INTERVAL;
+ *   timer.function = timer_func;
+ *   timer.data = 0;
+ *   add_timer(&timer);
+ *
+ * The 'data' parameter would get passed to the callback
+ * function. Starting with 4.15, you'd do something like this:
+ *
+ *   static void timer_func(struct timer_list *val);
+ *
+ *   timer_setup(&timer, timer_func, 0);
+ *   timer.expires = jiffies + STP_RELAY_TIMER_INTERVAL;
+ *   add_timer(&timer);
+ *   
+ * With the new code, the timer that caused the callback gets passed
+ * to the timer callback function. The 'data' field has been removed.
+ *
+ * So, we're going to use the new interface. To hide the differences
+ * between the callback function parameter type, we'll define a new
+ * type, 'stp_timer_callback_parameter_t'.
+ *
+ * If code needs to figure out the difference between the old and new
+ * interface, it should test the TIMER_TRACE_FLAGMASK define (which
+ * only exists in the new interface).
+ */
+
+#if defined(TIMER_TRACE_FLAGMASK) 
+/* This is the >= 4.15 kernel interface. */
+
+typedef struct timer_list * stp_timer_callback_parameter_t;
+
+#else
+/* This is the < 4.15 kernel interface. */
+
+typedef unsigned long stp_timer_callback_parameter_t;
+
+/**
+ * timer_setup - prepare a timer for first use
+ * @timer: the timer in question
+ * @callback: the function to call when timer expires
+ * @flags: any TIMER_* flags (note that anything other than 0 is an
+ * 	   error, since this compatibility function can't support any
+ *	   of the TIMER_* flags)
+ */
+#define timer_setup(timer, callback, flags)			\
+	{							\
+		init_timer((timer));				\
+		(timer)->function = callback;			\
+		(timer)->data = 0;				\
+		BUILD_BUG_ON_ZERO((flags) != 0);		\
+	}
+#endif
+
+#endif /* _TIMER_COMPATIBILITY_H_ */
diff --git a/runtime/time.c b/runtime/time.c
index 2e666d5..91ceafa 100644
--- a/runtime/time.c
+++ b/runtime/time.c
@@ -168,10 +168,10 @@ __stp_time_smp_callback(void *val)
 
 /* The timer callback is in a softIRQ -- interrupts enabled. */
 static void
-__stp_time_timer_callback(unsigned long val)
+__stp_time_timer_callback(stp_timer_callback_parameter_t unused)
 {
     stp_time_t *time =__stp_time_local_update();
-    (void) val;
+    (void) unused;
 
     /* PR6481: make sure IRQs are enabled before resetting the timer
        (IRQs are disabled and then reenabled in
@@ -200,9 +200,8 @@ __stp_init_time(void *info)
     time->freq = __stp_get_freq();
     __stp_time_local_update();
 
-    init_timer(&time->timer);
+    timer_setup(&time->timer, __stp_time_timer_callback, 0);
     time->timer.expires = jiffies + STP_TIME_SYNC_INTERVAL;
-    time->timer.function = __stp_time_timer_callback;
 
 #ifndef STAPCONF_ADD_TIMER_ON
     add_timer(&time->timer);
diff --git a/runtime/transport/relay_v2.c b/runtime/transport/relay_v2.c
index f81d75d..135951a 100644
--- a/runtime/transport/relay_v2.c
+++ b/runtime/transport/relay_v2.c
@@ -30,7 +30,7 @@
 #include <linux/debugfs.h>
 #include <linux/mm.h>
 #include <linux/relay.h>
-#include <linux/timer.h>
+#include "../linux/timer_compatibility.h"
 #include "../uidgid_compatibility.h"
 #include "relay_compat.h"
 
@@ -120,7 +120,7 @@ static void __stp_relay_wakeup_readers(struct rchan_buf *buf)
 		wake_up_interruptible(&buf->read_wait);
 }
 
-static void __stp_relay_wakeup_timer(unsigned long val)
+static void __stp_relay_wakeup_timer(stp_timer_callback_parameter_t unused)
 {
 #ifdef STP_BULKMODE
 	int i;
@@ -151,10 +151,8 @@ static void __stp_relay_wakeup_timer(unsigned long val)
 static void __stp_relay_timer_init(void)
 {
 	atomic_set(&_stp_relay_data.wakeup, 0);
-	init_timer(&_stp_relay_data.timer);
+	timer_setup(&_stp_relay_data.timer, __stp_relay_wakeup_timer, 0);
 	_stp_relay_data.timer.expires = jiffies + STP_RELAY_TIMER_INTERVAL;
-	_stp_relay_data.timer.function = __stp_relay_wakeup_timer;
-	_stp_relay_data.timer.data = 0;
 	add_timer(&_stp_relay_data.timer);
 	smp_mb();
 }
diff --git a/runtime/transport/transport.c b/runtime/transport/transport.c
index 3400f22..320fd18 100644
--- a/runtime/transport/transport.c
+++ b/runtime/transport/transport.c
@@ -311,7 +311,7 @@ static void _stp_detach(void)
 }
 
 
-static void _stp_ctl_work_callback(unsigned long val);
+static void _stp_ctl_work_callback(stp_timer_callback_parameter_t unused);
 
 /*
  * Called when stapio opens the control channel.
@@ -320,13 +320,12 @@ static void _stp_attach(void)
 {
 	dbug_trans(1, "attach\n");
 	_stp_pid = current->pid;
-  if (_stp_namespaces_pid < 1)
-    _stp_namespaces_pid = _stp_pid;
+	if (_stp_namespaces_pid < 1)
+		_stp_namespaces_pid = _stp_pid;
 	_stp_transport_data_fs_overwrite(0);
-	init_timer(&_stp_ctl_work_timer);
+
+	timer_setup(&_stp_ctl_work_timer, _stp_ctl_work_callback, 0);
 	_stp_ctl_work_timer.expires = jiffies + STP_CTL_TIMER_INTERVAL;
-	_stp_ctl_work_timer.function = _stp_ctl_work_callback;
-	_stp_ctl_work_timer.data= 0;
 	add_timer(&_stp_ctl_work_timer);
 }
 
@@ -341,7 +340,7 @@ static void _stp_attach(void)
  *	notified. Reschedules itself if someone is still attached
  *	to the cmd channel.
  */
-static void _stp_ctl_work_callback(unsigned long val)
+static void _stp_ctl_work_callback(stp_timer_callback_parameter_t unused)
 {
 	int do_io = 0;
 	unsigned long flags;
diff --git a/tapset-timers.cxx b/tapset-timers.cxx
index 1a40bcd..0ab4d69 100644
--- a/tapset-timers.cxx
+++ b/tapset-timers.cxx
@@ -122,9 +122,13 @@ timer_derived_probe_group::emit_module_decls (systemtap_session& s)
   s.op->newline(-1) << "};";
   s.op->newline();
 
-  s.op->newline() << "static void enter_timer_probe (unsigned long val) {";
+  s.op->newline() << "static void enter_timer_probe (stp_timer_callback_parameter_t val) {";
+  s.op->newline() << "#if defined(TIMER_TRACE_FLAGMASK)";
+  s.op->newline(1) << "struct stap_timer_probe* stp = container_of(val, struct stap_timer_probe, timer_list);";
+  s.op->newline(-1) << "#else";
   s.op->newline(1) << "struct stap_timer_probe* stp = & stap_timer_probes [val];";
-  s.op->newline() << "if ((atomic_read (session_state()) == STAP_SESSION_STARTING) ||";
+  s.op->newline(-1) << "#endif";
+  s.op->newline(1) << "if ((atomic_read (session_state()) == STAP_SESSION_STARTING) ||";
   s.op->newline() << "    (atomic_read (session_state()) == STAP_SESSION_RUNNING))";
   s.op->newline(1) << "mod_timer (& stp->timer_list, jiffies + ";
   emit_interval (s.op);
@@ -148,9 +152,11 @@ timer_derived_probe_group::emit_module_init (systemtap_session& s)
   s.op->newline() << "for (i=0; i<" << probes.size() << "; i++) {";
   s.op->newline(1) << "struct stap_timer_probe* stp = & stap_timer_probes [i];";
   s.op->newline() << "probe_point = stp->probe->pp;";
-  s.op->newline() << "init_timer (& stp->timer_list);";
-  s.op->newline() << "stp->timer_list.function = & enter_timer_probe;";
+
+  s.op->newline() << "timer_setup (& stp->timer_list, enter_timer_probe, 0);";
+  s.op->newline() << "#if !defined(TIMER_TRACE_FLAGMASK)";
   s.op->newline() << "stp->timer_list.data = i;"; // NB: important!
+  s.op->newline() << "#endif";
   // copy timer renew calculations from above :-(
   s.op->newline() << "stp->timer_list.expires = jiffies + ";
   emit_interval (s.op);
diff --git a/tapset/linux/scsi.stp b/tapset/linux/scsi.stp
index 44f686c..3577942 100644
--- a/tapset/linux/scsi.stp
+++ b/tapset/linux/scsi.stp
@@ -14,7 +14,7 @@
 #include <scsi/scsi_cmnd.h>
 #include <scsi/scsi_device.h>
 #include <scsi/scsi_host.h>
-#include <linux/timer.h>
+#include "linux/timer_compatibility.h"
 #include <linux/blkdev.h>
 %}
 
-- 
2.7.4