The patch titled
pids: kill signal_struct-> __pgrp/__session and friends
has been added to the -mm tree. Its filename is
pids-kill-now-unused-signal_struct-__pgrp-__session-and-friends.patch
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------------------------------------------------------
Subject: pids: kill signal_struct-> __pgrp/__session and friends
From: Oleg Nesterov <oleg@xxxxxxxxxx>
We are wasting 2 words in signal_struct without any reason to implement
task_pgrp_nr() and task_session_nr().
task_session_nr() has no callers since
2e2ba22ea4fd4bb85f0fa37c521066db6775cbef, we can remove it.
task_pgrp_nr() is still (I believe wrongly) used in fs/autofsX and
fs/coda.
This patch reimplements task_pgrp_nr() via task_pgrp_nr_ns(), and kills
__pgrp/__session and the related helpers.
The change in drivers/char/tty_io.c is cosmetic, but hopefully makes sense
anyway.
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Acked-by: Alan Cox <number6@xxxxxxxxxxxxxxxxx> [tty parts]
Cc: Cedric Le Goater <clg@xxxxxxxxxx>
Cc: Dave Hansen <haveblue@xxxxxxxxxx>
Cc: Eric Biederman <ebiederm@xxxxxxxxxxxx>
Cc: Pavel Emelyanov <xemul@xxxxxxxxxx>
Cc: Serge Hallyn <serue@xxxxxxxxxx>
Cc: Sukadev Bhattiprolu <sukadev@xxxxxxxxxxxxxxxxxx>
Cc: Roland McGrath <roland@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/char/tty_io.c | 4 +--
include/linux/sched.h | 43 +++++-----------------------------------
kernel/exit.c | 10 ++-------
kernel/fork.c | 2 -
kernel/sys.c | 4 ---
5 files changed, 12 insertions(+), 51 deletions(-)
diff -puN drivers/char/tty_io.c~pids-kill-now-unused-signal_struct-__pgrp-__session-and-friends drivers/char/tty_io.c
--- a/drivers/char/tty_io.c~pids-kill-now-unused-signal_struct-__pgrp-__session-and-friends
+++ a/drivers/char/tty_io.c
@@ -2679,7 +2679,7 @@ void __do_SAK(struct tty_struct *tty)
/* Kill the entire session */
do_each_pid_task(session, PIDTYPE_SID, p) {
printk(KERN_NOTICE "SAK: killed process %d"
- " (%s): task_session_nr(p)==tty->session\n",
+ " (%s): task_session(p)==tty->session\n",
task_pid_nr(p), p->comm);
send_sig(SIGKILL, p, 1);
} while_each_pid_task(session, PIDTYPE_SID, p);
@@ -2689,7 +2689,7 @@ void __do_SAK(struct tty_struct *tty)
do_each_thread(g, p) {
if (p->signal->tty == tty) {
printk(KERN_NOTICE "SAK: killed process %d"
- " (%s): task_session_nr(p)==tty->session\n",
+ " (%s): task_session(p)==tty->session\n",
task_pid_nr(p), p->comm);
send_sig(SIGKILL, p, 1);
continue;
diff -puN include/linux/sched.h~pids-kill-now-unused-signal_struct-__pgrp-__session-and-friends include/linux/sched.h
--- a/include/linux/sched.h~pids-kill-now-unused-signal_struct-__pgrp-__session-and-friends
+++ a/include/linux/sched.h
@@ -543,25 +543,8 @@ struct signal_struct {
struct list_head cpu_timers[3];
- /* job control IDs */
-
- /*
- * pgrp and session fields are deprecated.
- * use the task_session_Xnr and task_pgrp_Xnr routines below
- */
-
- union {
- pid_t pgrp __deprecated;
- pid_t __pgrp;
- };
-
struct pid *tty_old_pgrp;
- union {
- pid_t session __deprecated;
- pid_t __session;
- };
-
/* boolean value for session group leader */
int leader;
@@ -1453,16 +1436,6 @@ static inline int rt_task(struct task_st
return rt_prio(p->prio);
}
-static inline void set_task_session(struct task_struct *tsk, pid_t session)
-{
- tsk->signal->__session = session;
-}
-
-static inline void set_task_pgrp(struct task_struct *tsk, pid_t pgrp)
-{
- tsk->signal->__pgrp = pgrp;
-}
-
static inline struct pid *task_pid(struct task_struct *task)
{
return task->pids[PIDTYPE_PID].pid;
@@ -1536,11 +1509,6 @@ static inline pid_t task_tgid_vnr(struct
}
-static inline pid_t task_pgrp_nr(struct task_struct *tsk)
-{
- return tsk->signal->__pgrp;
-}
-
static inline pid_t task_pgrp_nr_ns(struct task_struct *tsk,
struct pid_namespace *ns)
{
@@ -1553,11 +1521,6 @@ static inline pid_t task_pgrp_vnr(struct
}
-static inline pid_t task_session_nr(struct task_struct *tsk)
-{
- return tsk->signal->__session;
-}
-
static inline pid_t task_session_nr_ns(struct task_struct *tsk,
struct pid_namespace *ns)
{
@@ -1569,6 +1532,12 @@ static inline pid_t task_session_vnr(str
return __task_pid_nr_ns(tsk, PIDTYPE_SID, NULL);
}
+/* obsolete, do not use */
+static inline pid_t task_pgrp_nr(struct task_struct *tsk)
+{
+ return task_pgrp_nr_ns(tsk, &init_pid_ns);
+}
+
/**
* pid_alive - check that a task structure is not stale
* @p: Task structure to be checked.
diff -puN kernel/exit.c~pids-kill-now-unused-signal_struct-__pgrp-__session-and-friends kernel/exit.c
--- a/kernel/exit.c~pids-kill-now-unused-signal_struct-__pgrp-__session-and-friends
+++ a/kernel/exit.c
@@ -359,16 +359,12 @@ static void reparent_to_kthreadd(void)
void __set_special_pids(struct pid *pid)
{
struct task_struct *curr = current->group_leader;
- pid_t nr = pid_nr(pid);
- if (task_session(curr) != pid) {
+ if (task_session(curr) != pid)
change_pid(curr, PIDTYPE_SID, pid);
- set_task_session(curr, nr);
- }
- if (task_pgrp(curr) != pid) {
+
+ if (task_pgrp(curr) != pid)
change_pid(curr, PIDTYPE_PGID, pid);
- set_task_pgrp(curr, nr);
- }
}
static void set_special_pids(struct pid *pid)
diff -puN kernel/fork.c~pids-kill-now-unused-signal_struct-__pgrp-__session-and-friends kernel/fork.c
--- a/kernel/fork.c~pids-kill-now-unused-signal_struct-__pgrp-__session-and-friends
+++ a/kernel/fork.c
@@ -1263,8 +1263,6 @@ static struct task_struct *copy_process(
p->signal->leader_pid = pid;
tty_kref_put(p->signal->tty);
p->signal->tty = tty_kref_get(current->signal->tty);
- set_task_pgrp(p, task_pgrp_nr(current));
- set_task_session(p, task_session_nr(current));
attach_pid(p, PIDTYPE_PGID, task_pgrp(current));
attach_pid(p, PIDTYPE_SID, task_session(current));
list_add_tail_rcu(&p->tasks, &init_task.tasks);
diff -puN kernel/sys.c~pids-kill-now-unused-signal_struct-__pgrp-__session-and-friends kernel/sys.c
--- a/kernel/sys.c~pids-kill-now-unused-signal_struct-__pgrp-__session-and-friends
+++ a/kernel/sys.c
@@ -1004,10 +1004,8 @@ SYSCALL_DEFINE2(setpgid, pid_t, pid, pid
if (err)
goto out;
- if (task_pgrp(p) != pgrp) {
+ if (task_pgrp(p) != pgrp)
change_pid(p, PIDTYPE_PGID, pgrp);
- set_task_pgrp(p, pid_nr(pgrp));
- }
err = 0;
out:
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
linux-next.patch
pipe_rdwr_fasync-fix-the-error-handling-to-prevent-the-leak-crash.patch
get_mm_hiwater_xxx-trivial-s-define-inline.patch
getrusage-fill-ru_maxrss-value.patch
pids-document-task_pgrp-task_session-is-not-safe-without-tasklist-rcu.patch
pids-document-task_pgrp-task_session-is-not-safe-without-tasklist-rcu-fix.patch
pids-improve-get_task_pid-to-fix-the-unsafe-sys_wait4-task_pgrp.patch
pids-refactor-vnr-nr_ns-helpers-to-make-them-safe.patch
pids-kill-now-unused-signal_struct-__pgrp-__session-and-friends.patch
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