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[PATCH 0/4] add __init attribute

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  [PATCH 0/4] add __init attribute Julia Lawall <Julia.Lawall@lip6.fr> - 2016-04-19 14:50 +0200
    [PATCH 1/4] thermal: of: add __init attribute Julia Lawall <Julia.Lawall@lip6.fr> - 2016-04-19 14:50 +0200

#1382473 — [PATCH 0/4] add __init attribute

Add __init attribute on a function that is only called from other __init
functions and that is not inlined.

The complete semantic patch used to detect the need for this change is
below.  This semantic patch checks for local static non-init functions that
are called from an __init function and are not called from any other
function.

<smpl>
@initialize:ocaml@
@@

let itbl = Hashtbl.create 101
let ltbl = Hashtbl.create 101
let thefile = ref ""

let hashadd t k =
  let cell =
    try Hashtbl.find t k
    with Not_found ->
      let cell = ref 0 in
      Hashtbl.add t k cell;
      cell in
  cell := !cell + 1

let hashget t k = try !(Hashtbl.find t k) with Not_found -> 0

let seen  = ref []

@script:ocaml@
@@

(let file = List.hd (Coccilib.files()) in
thefile := file;
let file =
    try List.hd(List.tl (Str.split (Str.regexp "/linux-next/") file))
    with _ -> file in
let ofile = "/var/julia/linux-next/" ^
      (Filename.chop_extension file) ^ ".o" in
if not(Sys.file_exists ofile)
then Coccilib.exit());

Hashtbl.clear itbl;
Hashtbl.clear ltbl;
seen := []

@r@
identifier f;
@@

__init f(...) { ... }

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

Hashtbl.add itbl f ()

@s disable optional_attributes@
identifier f;
@@

static f(...) { ... }

@script:ocaml@
f << s.f;
@@

Hashtbl.add ltbl f ()

@t exists@
identifier f,g;
position p;
@@

__init f(...) { ... when any
   g@p(...)
   ... when any
 }

@script:ocaml@
g << t.g;
_p << t.p;
@@

if not (Hashtbl.mem ltbl g) || Hashtbl.mem itbl g
then Coccilib.include_match false

@ok1 disable optional_attributes exists@
identifier f,t.g;
@@

f(...) { ... when any
   g
   ... when any
 }

@ok2 disable optional_attributes exists@
identifier i,j,fld,t.g;
@@

struct i j = { .fld = g, };

@ok3 disable optional_attributes exists@
identifier t.g;
declarer d;
@@

d(...,g,...);

@ok4 disable optional_attributes exists@
identifier t.g;
expression e;
@@

(
e(...,g,...)
|
e(...,&g,...)
|
e = &g
|
e = g
)

@script:ocaml depends on !ok1 && !ok2 && !ok3 && !ok4@
g << t.g;
@@

let file = !thefile in
let file =
    try List.hd(List.tl (Str.split (Str.regexp "/linux-next/") file))
    with _ -> file in
if not(List.mem (g,file) !seen)
then
  begin
    seen := (g,file) :: !seen;
    let ofile = "/var/julia/linux-next/" ^
      (Filename.chop_extension file) ^ ".o" in
    if Sys.file_exists ofile
    then
      let l =
	Common.cmd_to_list
	  (Printf.sprintf
	     "objdump -x %s | grep -w %s | grep -w F | grep .text.unlikely"
	     ofile g) in
      match l with
	[] -> Coccilib.include_match false
      | _ ->
	  Printf.printf "Info for %s %s\n" file g;
	  List.iter
	    (function l -> Printf.printf "%s\n" l)
	    l;
	  Printf.printf "\n"; flush stdout
    else Coccilib.include_match false
  end
else Coccilib.include_match false

@depends on !ok1 && !ok2 && !ok3 && !ok4@
identifier t.g;
@@

- g
+__init g
 (...) { ... }
</smpl>

---

 drivers/mtd/maps/ck804xrom.c |    4 ++--
 drivers/mtd/maps/esb2rom.c   |    4 ++--
 drivers/mtd/maps/ichxrom.c   |    4 ++--
 drivers/thermal/of-thermal.c |    4 ++--
 drivers/mtd/devices/pmc551.c |    2 +-
 drivers/mtd/nand/nandsim.c |    6 +++---

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#1382476 — [PATCH 1/4] thermal: of: add __init attribute

Add __init attribute on a function that is only called from other __init
functions and that is not inlined, at least with gcc version 4.8.4 on an
x86 machine with allyesconfig.  Currently, the function is put in the
.text.unlikely segment.  Declaring it as __init will cause it to be put in
the .init.text and to disappear after initialization.

The result of objdump -x on the function before the change is as follows:

0000000000000086 l     F .text.unlikely 0000000000000739 thermal_of_build_thermal_zone

And after the change it is as follows:

0000000000000000 l     F .init.text	0000000000000734 thermal_of_build_thermal_zone

Done with the help of Coccinelle.  The semantic patch checks for local
static non-init functions that are called from an __init function and are
not called from any other function.

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>

---
 drivers/thermal/of-thermal.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/thermal/of-thermal.c b/drivers/thermal/of-thermal.c
index 8528802..b8e509c 100644
--- a/drivers/thermal/of-thermal.c
+++ b/drivers/thermal/of-thermal.c
@@ -811,8 +811,8 @@ static int thermal_of_populate_trip(struct device_node *np,
  * otherwise, it returns a corresponding ERR_PTR(). Caller must
  * check the return value with help of IS_ERR() helper.
  */
-static struct __thermal_zone *
-thermal_of_build_thermal_zone(struct device_node *np)
+static struct __thermal_zone
+__init *thermal_of_build_thermal_zone(struct device_node *np)
 {
 	struct device_node *child = NULL, *gchild;
 	struct __thermal_zone *tz;

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