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Message-Id: <20180711024459.10654-3-ebiederm@xmission.com>
Date: Tue, 10 Jul 2018 21:44:51 -0500
From: "Eric W. Biederman" <ebiederm@...ssion.com>
To: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Oleg Nesterov <oleg@...hat.com>,
Andrew Morton <akpm@...ux-foundation.org>,
linux-kernel@...r.kernel.org, Wen Yang <wen.yang99@....com.cn>,
majiang <ma.jiang@....com.cn>,
"Eric W. Biederman" <ebiederm@...ssion.com>
Subject: [RFC][PATCH 03/11] pids: Compute task_tgid using signal->leader_pid
The cost is the the same and this removes the need
to worry about complications that come from de_thread
and group_leader changing.
__task_pid_nr_ns has been updated to take advantage of this change.
Signed-off-by: "Eric W. Biederman" <ebiederm@...ssion.com>
---
arch/ia64/kernel/asm-offsets.c | 2 +-
arch/ia64/kernel/fsys.S | 8 ++++----
drivers/platform/x86/thinkpad_acpi.c | 1 +
fs/fuse/file.c | 1 +
fs/notify/fanotify/fanotify.c | 1 +
include/linux/sched.h | 5 -----
include/linux/sched/signal.h | 5 +++++
include/net/scm.h | 1 +
kernel/pid.c | 15 ++++++++-------
9 files changed, 22 insertions(+), 17 deletions(-)
diff --git a/arch/ia64/kernel/asm-offsets.c b/arch/ia64/kernel/asm-offsets.c
index f4db2168d1b8..f5433bb7f04a 100644
--- a/arch/ia64/kernel/asm-offsets.c
+++ b/arch/ia64/kernel/asm-offsets.c
@@ -50,7 +50,6 @@ void foo(void)
DEFINE(IA64_TASK_BLOCKED_OFFSET,offsetof (struct task_struct, blocked));
DEFINE(IA64_TASK_CLEAR_CHILD_TID_OFFSET,offsetof (struct task_struct, clear_child_tid));
- DEFINE(IA64_TASK_GROUP_LEADER_OFFSET, offsetof (struct task_struct, group_leader));
DEFINE(IA64_TASK_TGIDLINK_OFFSET, offsetof (struct task_struct, pids[PIDTYPE_PID].pid));
DEFINE(IA64_PID_LEVEL_OFFSET, offsetof (struct pid, level));
DEFINE(IA64_PID_UPID_OFFSET, offsetof (struct pid, numbers[0]));
@@ -68,6 +67,7 @@ void foo(void)
DEFINE(IA64_SIGNAL_GROUP_STOP_COUNT_OFFSET,offsetof (struct signal_struct,
group_stop_count));
DEFINE(IA64_SIGNAL_SHARED_PENDING_OFFSET,offsetof (struct signal_struct, shared_pending));
+ DEFINE(IA64_SIGNAL_LEADER_PID_OFFSET, offsetof (struct signal_struct, leader_pid));
BLANK();
diff --git a/arch/ia64/kernel/fsys.S b/arch/ia64/kernel/fsys.S
index fe742ffafc7a..eaf5a0d6f3e0 100644
--- a/arch/ia64/kernel/fsys.S
+++ b/arch/ia64/kernel/fsys.S
@@ -62,16 +62,16 @@ ENTRY(fsys_getpid)
.prologue
.altrp b6
.body
- add r17=IA64_TASK_GROUP_LEADER_OFFSET,r16
+ add r17=IA64_TASK_SIGNAL_OFFSET,r16
;;
- ld8 r17=[r17] // r17 = current->group_leader
+ ld8 r17=[r17] // r17 = current->signal
add r9=TI_FLAGS+IA64_TASK_SIZE,r16
;;
ld4 r9=[r9]
- add r17=IA64_TASK_TGIDLINK_OFFSET,r17
+ add r17=IA64_SIGNAL_LEADER_PID_OFFSET,r17
;;
and r9=TIF_ALLWORK_MASK,r9
- ld8 r17=[r17] // r17 = current->group_leader->pids[PIDTYPE_PID].pid
+ ld8 r17=[r17] // r17 = current->signal->leader_pid
;;
add r8=IA64_PID_LEVEL_OFFSET,r17
;;
diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index cae9b0595692..d556e95c532c 100644
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -57,6 +57,7 @@
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/sched.h>
+#include <linux/sched/signal.h>
#include <linux/kthread.h>
#include <linux/freezer.h>
#include <linux/delay.h>
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index a201fb0ac64f..b00a3f126a89 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -12,6 +12,7 @@
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/sched.h>
+#include <linux/sched/signal.h>
#include <linux/module.h>
#include <linux/compat.h>
#include <linux/swap.h>
diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index f90842efea13..6e828cb82e5e 100644
--- a/fs/notify/fanotify/fanotify.c
+++ b/fs/notify/fanotify/fanotify.c
@@ -8,6 +8,7 @@
#include <linux/mount.h>
#include <linux/sched.h>
#include <linux/sched/user.h>
+#include <linux/sched/signal.h>
#include <linux/types.h>
#include <linux/wait.h>
#include <linux/audit.h>
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 87bf02d93a27..a461ff89a3af 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1202,11 +1202,6 @@ static inline struct pid *task_pid(struct task_struct *task)
return task->pids[PIDTYPE_PID].pid;
}
-static inline struct pid *task_tgid(struct task_struct *task)
-{
- return task->group_leader->pids[PIDTYPE_PID].pid;
-}
-
/*
* Without tasklist or RCU lock it is not safe to dereference
* the result of task_pgrp/task_session even if task == current,
diff --git a/include/linux/sched/signal.h b/include/linux/sched/signal.h
index d8ef0a3d2e7e..b95a272c1ab5 100644
--- a/include/linux/sched/signal.h
+++ b/include/linux/sched/signal.h
@@ -564,6 +564,11 @@ struct pid *task_pid_type(struct task_struct *task, enum pid_type type)
return task->pids[type].pid;
}
+static inline struct pid *task_tgid(struct task_struct *task)
+{
+ return task->signal->leader_pid;
+}
+
static inline int get_nr_threads(struct task_struct *tsk)
{
return tsk->signal->nr_threads;
diff --git a/include/net/scm.h b/include/net/scm.h
index 903771c8d4e3..1ce365f4c256 100644
--- a/include/net/scm.h
+++ b/include/net/scm.h
@@ -8,6 +8,7 @@
#include <linux/security.h>
#include <linux/pid.h>
#include <linux/nsproxy.h>
+#include <linux/sched/signal.h>
/* Well, we should have at least one descriptor open
* to accept passed FDs 8)
diff --git a/kernel/pid.c b/kernel/pid.c
index 157fe4b19971..d0de2b59f86f 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -421,13 +421,14 @@ pid_t __task_pid_nr_ns(struct task_struct *task, enum pid_type type,
if (!ns)
ns = task_active_pid_ns(current);
if (likely(pid_alive(task))) {
- if (type != PIDTYPE_PID) {
- if (type == __PIDTYPE_TGID)
- type = PIDTYPE_PID;
-
- task = task->group_leader;
- }
- nr = pid_nr_ns(rcu_dereference(task->pids[type].pid), ns);
+ struct pid *pid;
+ if (type == PIDTYPE_PID)
+ pid = task_pid(task);
+ else if (type == __PIDTYPE_TGID)
+ pid = task_tgid(task);
+ else
+ pid = rcu_dereference(task->group_leader->pids[type].pid);
+ nr = pid_nr_ns(pid, ns);
}
rcu_read_unlock();
--
2.17.1
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