[Devel] + attach_pid-with-struct-pid-parameter.patch added to -mm tree

[akpm at linux-foundation.org]

The patch titled
     attach_pid() with struct pid parameter
has been added to the -mm tree.  Its filename is
     attach_pid-with-struct-pid-parameter.patch

*** Remember to use Documentation/SubmitChecklist when testing your code ***

See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this

------------------------------------------------------
Subject: attach_pid() with struct pid parameter
From: Sukadev Bhattiprolu <sukadev at us.ibm.com>

attach_pid() currently takes a pid_t and then uses find_pid() to find the
corresponding struct pid.  Sometimes we already have the struct pid.  We can
then skip find_pid() if attach_pid() were to take a struct pid parameter.

Signed-off-by: Sukadev Bhattiprolu <sukadev at us.ibm.com>
Cc: Cedric Le Goater <clg at fr.ibm.com>
Cc: Dave Hansen <haveblue at us.ibm.com>
Cc: Serge Hallyn <serue at us.ibm.com>
Cc: <containers at lists.osdl.org>
Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
---

 fs/exec.c           |    2 +-
 include/linux/pid.h |    3 +--
 kernel/exit.c       |    4 ++--
 kernel/fork.c       |   11 +++++++----
 kernel/pid.c        |    9 ++++++---
 kernel/sys.c        |    2 +-
 6 files changed, 18 insertions(+), 13 deletions(-)

diff -puN fs/exec.c~attach_pid-with-struct-pid-parameter fs/exec.c
--- a/fs/exec.c~attach_pid-with-struct-pid-parameter
+++ a/fs/exec.c
@@ -701,7 +701,7 @@ static int de_thread(struct task_struct 
 		 */
 		detach_pid(tsk, PIDTYPE_PID);
 		tsk->pid = leader->pid;
-		attach_pid(tsk, PIDTYPE_PID,  tsk->pid);
+		attach_pid(tsk, PIDTYPE_PID,  find_pid(tsk->pid));
 		transfer_pid(leader, tsk, PIDTYPE_PGID);
 		transfer_pid(leader, tsk, PIDTYPE_SID);
 		list_replace_rcu(&leader->tasks, &tsk->tasks);
diff -puN include/linux/pid.h~attach_pid-with-struct-pid-parameter include/linux/pid.h
--- a/include/linux/pid.h~attach_pid-with-struct-pid-parameter
+++ a/include/linux/pid.h
@@ -76,8 +76,7 @@ extern struct pid *get_task_pid(struct t
  * write-held.
  */
 extern int FASTCALL(attach_pid(struct task_struct *task,
-				enum pid_type type, int nr));
-
+				enum pid_type type, struct pid *pid));
 extern void FASTCALL(detach_pid(struct task_struct *task, enum pid_type));
 extern void FASTCALL(transfer_pid(struct task_struct *old,
 				  struct task_struct *new, enum pid_type));
diff -puN kernel/exit.c~attach_pid-with-struct-pid-parameter kernel/exit.c
--- a/kernel/exit.c~attach_pid-with-struct-pid-parameter
+++ a/kernel/exit.c
@@ -299,12 +299,12 @@ void __set_special_pids(pid_t session, p
 	if (process_session(curr) != session) {
 		detach_pid(curr, PIDTYPE_SID);
 		set_signal_session(curr->signal, session);
-		attach_pid(curr, PIDTYPE_SID, session);
+		attach_pid(curr, PIDTYPE_SID, find_pid(session));
 	}
 	if (process_group(curr) != pgrp) {
 		detach_pid(curr, PIDTYPE_PGID);
 		curr->signal->pgrp = pgrp;
-		attach_pid(curr, PIDTYPE_PGID, pgrp);
+		attach_pid(curr, PIDTYPE_PGID, find_pid(pgrp));
 	}
 }
 
diff -puN kernel/fork.c~attach_pid-with-struct-pid-parameter kernel/fork.c
--- a/kernel/fork.c~attach_pid-with-struct-pid-parameter
+++ a/kernel/fork.c
@@ -1242,16 +1242,19 @@ static struct task_struct *copy_process(
 		tracehook_init_task(p);
 
 		if (thread_group_leader(p)) {
+			pid_t pgid = process_group(current);
+			pid_t sid = process_session(current);
+
 			p->signal->tty = current->signal->tty;
-			p->signal->pgrp = process_group(current);
+			p->signal->pgrp = pgid;
 			set_signal_session(p->signal, process_session(current));
-			attach_pid(p, PIDTYPE_PGID, process_group(p));
-			attach_pid(p, PIDTYPE_SID, process_session(p));
+			attach_pid(p, PIDTYPE_PGID, find_pid(pgid));
+			attach_pid(p, PIDTYPE_SID, find_pid(sid));
 
 			list_add_tail_rcu(&p->tasks, &init_task.tasks);
 			__get_cpu_var(process_counts)++;
 		}
-		attach_pid(p, PIDTYPE_PID, p->pid);
+		attach_pid(p, PIDTYPE_PID, find_pid(p->pid));
 		nr_threads++;
 	}
 
diff -puN kernel/pid.c~attach_pid-with-struct-pid-parameter kernel/pid.c
--- a/kernel/pid.c~attach_pid-with-struct-pid-parameter
+++ a/kernel/pid.c
@@ -247,13 +247,16 @@ struct pid * fastcall find_pid(int nr)
 }
 EXPORT_SYMBOL_GPL(find_pid);
 
-int fastcall attach_pid(struct task_struct *task, enum pid_type type, int nr)
+/*
+ * attach_pid() must be called with the tasklist_lock write-held.
+ */
+int fastcall attach_pid(struct task_struct *task, enum pid_type type,
+		struct pid *pid)
 {
 	struct pid_link *link;
-	struct pid *pid;
 
 	link = &task->pids[type];
-	link->pid = pid = find_pid(nr);
+	link->pid = pid;
 	hlist_add_head_rcu(&link->node, &pid->tasks[type]);
 
 	return 0;
diff -puN kernel/sys.c~attach_pid-with-struct-pid-parameter kernel/sys.c
--- a/kernel/sys.c~attach_pid-with-struct-pid-parameter
+++ a/kernel/sys.c
@@ -1486,7 +1486,7 @@ asmlinkage long sys_setpgid(pid_t pid, p
 	if (process_group(p) != pgid) {
 		detach_pid(p, PIDTYPE_PGID);
 		p->signal->pgrp = pgid;
-		attach_pid(p, PIDTYPE_PGID, pgid);
+		attach_pid(p, PIDTYPE_PGID, find_pid(pgid));
 	}
 
 	err = 0;
_

Patches currently in -mm which might be from sukadev at us.ibm.com are

attach_pid-with-struct-pid-parameter.patch
statically-initialize-struct-pid-for-swapper.patch
explicitly-set-pgid-and-sid-of-init-process.patch
use-struct-pid-parameter-in-copy_process.patch
remove-the-likelypid-check-in-copy_process.patch
use-task_pgrp-task_session-in-copy_process.patch
kill-unused-sesssion-and-group-values-in-rocket-driver.patch
fix-some-coding-style-errors-in-autofs.patch
replace-pid_t-in-autofs-with-struct-pid-reference.patch

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