From 7a36094d61bfe9843de5484ff0140227983ac5d5 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Tue, 26 Sep 2017 12:45:33 -0500 Subject: [PATCH] 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" --- 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 #include #include +#include #include #include #include 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 #include #include +#include #include #include #include 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 #include #include +#include #include #include #include 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 #include #include +#include /* 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();