batman-adv: setup_timer() -> timer_setup()

From: Kees Cook <[email protected]>

This converts all remaining cases of the old setup_timer() API into using timer_setup(), where the callback argument is the structure already holding the struct timer_list. These should have no behavioral changes, since they just change which pointer is passed into the callback with the same available pointers after conversion.

---
 compat-include/linux/timer.h | 59 ++++++++++++++++++++++++++++++++++++++++++++
 net/batman-adv/tp_meter.c    | 14 +++++------
 2 files changed, 65 insertions(+), 8 deletions(-)
 create mode 100644 compat-include/linux/timer.h

new file mode 100644
index 0000000..750b6ae
@@ -0,0 +1,59 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (C) 2007-2017  B.A.T.M.A.N. contributors:
+ *
+ * Marek Lindner, Simon Wunderlich
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ *
+ * License-Filename: LICENSES/preferred/GPL-2.0
+ *
+ * This file contains macros for maintaining compatibility with older versions
+ * of the Linux kernel.
+ */
+
+#ifndef _NET_BATMAN_ADV_COMPAT_LINUX_TIMER_H
+#define _NET_BATMAN_ADV_COMPAT_LINUX_TIMER_H
+
+#include <linux/version.h>
+#include_next <linux/timer.h>
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(3, 7, 0)
+
+#define __setup_timer(_timer, _fn, _data, _flags) \
+	do { \
+		init_timer(_timer); \
+		(_timer)->function = (_fn); \
+		(_timer)->data = (_data); \
+	} while (0)
+
+#endif /* < KERNEL_VERSION(3, 7, 0) */
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 14, 0)
+
+#define TIMER_DATA_TYPE		unsigned long
+#define TIMER_FUNC_TYPE		void (*)(TIMER_DATA_TYPE)
+
+static inline void timer_setup(struct timer_list *timer,
+			       void (*callback)(struct timer_list *),
+			       unsigned int flags)
+{
+	__setup_timer(timer, (TIMER_FUNC_TYPE)callback,
+		      (TIMER_DATA_TYPE)timer, flags);
+}
+
+#define from_timer(var, callback_timer, timer_fieldname) \
+	container_of(callback_timer, typeof(*var), timer_fieldname)
+
+#endif /* < KERNEL_VERSION(4, 14, 0) */
+
+#endif /* _NET_BATMAN_ADV_COMPAT_LINUX_TIMER_H */

index 4b90033..15cd213 100644
@@ -488,9 +488,9 @@ static void batadv_tp_reset_sender_timer(struct batadv_tp_vars *tp_vars)
  * Switch to Slow Start, set the ss_threshold to half of the current cwnd and
  * reset the cwnd to 3*MSS
  */
-static void batadv_tp_sender_timeout(unsigned long arg)
+static void batadv_tp_sender_timeout(struct timer_list *t)
 {
-	struct batadv_tp_vars *tp_vars = (struct batadv_tp_vars *)arg;
+	struct batadv_tp_vars *tp_vars = from_timer(tp_vars, t, timer);
 	struct batadv_priv *bat_priv = tp_vars->bat_priv;
 
 	if (atomic_read(&tp_vars->sending) == 0)

@@ -1020,8 +1020,7 @@ void batadv_tp_start(struct batadv_priv *bat_priv, const u8 *dst,
 	atomic64_set(&tp_vars->tot_sent, 0);
 
 	kref_get(&tp_vars->refcount);
-	setup_timer(&tp_vars->timer, batadv_tp_sender_timeout,
-		    (unsigned long)tp_vars);
+	timer_setup(&tp_vars->timer, batadv_tp_sender_timeout, 0);
 
 	tp_vars->bat_priv = bat_priv;
 	tp_vars->start_time = jiffies;

@@ -1109,9 +1108,9 @@ static void batadv_tp_reset_receiver_timer(struct batadv_tp_vars *tp_vars)
  *  reached without received ack
  * @arg: address of the related tp_vars
  */
-static void batadv_tp_receiver_shutdown(unsigned long arg)
+static void batadv_tp_receiver_shutdown(struct timer_list *t)
 {
-	struct batadv_tp_vars *tp_vars = (struct batadv_tp_vars *)arg;
+	struct batadv_tp_vars *tp_vars = from_timer(tp_vars, t, timer);
 	struct batadv_tp_unacked *un, *safe;
 	struct batadv_priv *bat_priv;
 

@@ -1373,8 +1372,7 @@ batadv_tp_init_recv(struct batadv_priv *bat_priv,
 	hlist_add_head_rcu(&tp_vars->list, &bat_priv->tp_list);
 
 	kref_get(&tp_vars->refcount);
-	setup_timer(&tp_vars->timer, batadv_tp_receiver_shutdown,
-		    (unsigned long)tp_vars);
+	timer_setup(&tp_vars->timer, batadv_tp_receiver_shutdown, 0);
 
 	batadv_tp_reset_receiver_timer(tp_vars);
 

2.11.0

The commit e99e88a9d2b0 ("treewide: setup_timer() -> timer_setup()") changed the argument name and type of the timer function but didn't adjust the kernel-doc of these functions.

---
Cc: Kees Cook <[email protected]>

---
 net/batman-adv/tp_meter.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

index 15cd213..ebc4e22 100644
@@ -482,7 +482,7 @@ static void batadv_tp_reset_sender_timer(struct batadv_tp_vars *tp_vars)
 
 /**
  * batadv_tp_sender_timeout - timer that fires in case of packet loss
- * @arg: address of the related tp_vars
+ * @t: address to timer_list inside tp_vars
  *
  * If fired it means that there was packet loss.
  * Switch to Slow Start, set the ss_threshold to half of the current cwnd and

@@ -1106,7 +1106,7 @@ static void batadv_tp_reset_receiver_timer(struct batadv_tp_vars *tp_vars)
 /**
  * batadv_tp_receiver_shutdown - stop a tp meter receiver when timeout is
  *  reached without received ack
- * @arg: address of the related tp_vars
+ * @t: address to timer_list inside tp_vars
  */
 static void batadv_tp_receiver_shutdown(struct timer_list *t)
 {

2.11.0

I wonder if there is a way for Coccinelle to change kernel-doc?

-Kees

Kees Cook
Pixel Security

It can't change it, but with some cleverness (ie python/ocaml code) it can be used to find problems. I've attached a semantic patch that I wrote for this. It gives reports like:

drivers/acpi/arm64/iort.c:864 dma_size doesn't appear in ids: dev dma_addr size

Indeed the code has:

/**
* iort_dma_setup() - Set-up device DMA parameters.
*
* @dev: device to configure
* @dma_addr: device DMA address result pointer
* @size: DMA range size result pointer
*/
void iort_dma_setup(struct device *dev, u64 *dma_addr, u64 *dma_size)

So the kerneldoc has the wrong name. There are also things like this:

drivers/acpi/acpica/utdebug.c:617 acpi_trace_point doesn't match preceding
comment: begin

Here the code is:

/******************************************************************************\
*
*
* FUNCTION: acpi_trace_point
*

 * PARAMETERS:  type                - Trace event type
 *              begin               - TRUE if before execution
 *              aml                 - Executed AML address
 *              pathname            - Object path
 *              pointer             - Pointer to the related object

*
* RETURN: None
*
* DESCRIPTION: Interpreter execution trace.
*

******************************************************************************\
/

void
acpi_trace_point(acpi_trace_event_type type, u8 begin, u8 *aml, char *pathname)

So the rule doesn't seem to know about this kind of documentation.

julia

@initialize:ocaml@
@@

let tbl = ref []
let fnstart = ref []
let success = Hashtbl.create 101
let thefile = ref ""
let parsed = ref []
let nea = ref []

let parse file =
thefile := List.nth (Str.split (Str.regexp "linux-next/") file) 1; let i = open_in file in
let startline = ref 0 in
let fn = ref "" in
let ids = ref [] in
let rec inside n =

    let l = input_line i in
    let n = n + 1 in
    match Str.split_delim (Str.regexp_string "*/") l with
      before::after::_ ->
	(if not (!fn = "")
	then tbl := (!startline,n,!fn,List.rev !ids)::!tbl);
	startline := 0;
	fn := "";
	ids := [];
	outside n
    | _ ->
	(match Str.split (Str.regexp "[ \t]+") l with
	  "*"::name::rest ->
	    let len = String.length name in
	    (if !fn = "" && len > 2 && String.sub name (len-2) 2 = "()"
	    then fn := String.sub name 0 (len-2)
	    else if !fn = "" && (not (rest = [])) && List.hd rest = "-"
	    then
	      if String.get name (len-1) = ':'
	      then fn := String.sub name 0 (len-1)
	      else fn := name
	    else if not(!fn = "") && len > 2 &&
	      String.get name 0 = '@' && String.get name (len-1) = ':'
	    then ids := (String.sub name 1 (len-2)) :: !ids);
	| _ -> ());
	inside n

and outside n =
let l = input_line i in
let n = n + 1 in
if String.length l > 2 && String.sub l 0 3 = "/**" then
begin
startline := n;
inside n
end
else outside n in
try outside 0 with End_of_file -> ()

let hashadd tbl k v =
let cell =

    try Hashtbl.find tbl k
    with Not_found ->
      let cell = ref [] in
      Hashtbl.add tbl k cell;
      cell in

cell := v :: !cell

@script:ocaml@
@@

tbl := [];
fnstart := [];
Hashtbl.clear success;
parsed := [];
nea := [];
parse (List.hd (Coccilib.files()))

@r@
identifier f;
position p;
@@

f@p(...) { ... }

@script:ocaml@
p << r.p;
f << r.f;
@@

parsed := f :: !parsed;
fnstart := (List.hd p).line :: !fnstart

@param@
identifier f;
type T;
identifier i;
parameter list[n] ps;
parameter list[n1] ps1;
position p;
@@

f@p(ps,T i,ps1) { ... }

@script:ocaml@
@@

tbl := List.rev (List.sort compare !tbl)

@script:ocaml@
p << param.p;
f << param.f;
@@

let myline = (List.hd p).line in
let prevline =
List.fold_left
(fun prev x ->
if x < myline
then max x prev
else prev)
0 !fnstart in
let _ =
List.exists

    (function (st,fn,nm,ids) ->
      if prevline < st && myline > st && prevline < fn && myline > fn
      then
	begin
	  (if not (String.lowercase f = String.lowercase nm)
	  then
	    Printf.printf "%s:%d %s doesn't match preceding comment: %s\n"
	      !thefile myline f nm);
	  true
	end
      else false)
    !tbl in

()

@script:ocaml@
p << param.p;
n << param.n;
n1 << param.n1;
i << param.i;
f << param.f;
@@

let myline = (List.hd p).line in
let prevline =
List.fold_left
(fun prev x ->
if x < myline
then max x prev
else prev)
0 !fnstart in
let _ =
List.exists

    (function (st,fn,nm,ids) ->
      if prevline < st && myline > st && prevline < fn && myline > fn
      then
	begin
	  (if List.mem i ids then hashadd success (st,fn,nm) i);
	  (if ids = [] (* arg list seems not obligatory *)
	  then ()
	  else if not (List.mem i ids)
	  then
	    Printf.printf "%s:%d %s doesn't appear in ids: %s\n"
	      !thefile myline i (String.concat " " ids)
	  else if List.length ids <= n || List.length ids <= n1
	  then
	    (if not (List.mem f !nea)
	    then
	      begin
		nea := f :: !nea;
		Printf.printf "%s:%d %s not enough args\n" !thefile myline f;
	      end)
	  else
	    let foundid = List.nth ids n in
	    let efoundid = List.nth (List.rev ids) n1 in
	    if not(foundid = i || efoundid = i)
	    then
	      Printf.printf "%s:%d %s wrong arg in position %d: %s\n"
		!thefile myline i n foundid);
	  true
	end
      else false)
    !tbl in

()

@script:ocaml@
@@
List.iter
(function (st,fn,nm,ids) ->
if List.mem nm !parsed
then
let entry =
try !(Hashtbl.find success (st,fn,nm))
with Not_found -> [] in
List.iter
(fun id ->
if not (List.mem id entry) && not (id = "...") then Printf.printf "%s:%d %s not used\n" !thefile st id)
ids)
!tbl

Picked this series up into 295ef829 and 258e419d

Thank you!
Simon