[PATCH 4/6] Use pid_to_nr() in process info functions
Subject: [PATCH 4/6] Use pid_to_nr() in process info functions From: Sukadev Bhattiprolu <sukadev@us.ibm.com> Use pid_to_nr() function in getppid(), getpgid() and getsid() functions so they return the correct pid_t for processes in multiple pid namespaces. Note: We don't need pid_to_nr() in getpid() because the process always "sees itself" as being in its active pid namespace. Using pid_to_nr() in getpid() would unnecessarily hurt its performance. Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com> --- include/linux/sched.h | 24 ++++++++++++++++++++++++ kernel/sys.c | 10 +++++----- kernel/timer.c | 2 +- 3 files changed, 30 insertions(+), 6 deletions(-) Index: lx26-22-rc6-mm1/include/linux/sched.h =================================================================== --- lx26-22-rc6-mm1.orig/include/linux/sched.h 2007-07-05 18:53:42.000000000 -0700 +++ lx26-22-rc6-mm1/include/linux/sched.h 2007-07-05 18:57:34.000000000 -0700 @@ -1200,6 +1200,30 @@ static inline struct pid *task_tgid(stru return task->group_leader->pids[PIDTYPE_PID].pid; } +/* NOTE: Caller must hold rcu_readlock() */ +static inline struct pid *task_parent_tgid(struct task_struct *task) +{ + return task_tgid(rcu_dereference(task->real_parent)); +} + +/* NOTE: Caller must hold rcu_readlock() */ +static inline struct pid *task_parent_pid(struct task_struct *task) +{ + return task_pid(rcu_dereference(task->real_parent)); +} + +/* NOTE: Caller must hold rcu_readlock() */ +static inline struct pid *task_tracer_tgid(struct task_struct *task) +{ + return task_tgid(rcu_dereference(task->parent)); +} + +/* NOTE: Caller must hold rcu_readlock() */ +static inline struct pid *task_tracer_pid(struct task_struct *task) +{ + return task_pid(rcu_dereference(task->parent)); +} + static inline struct pid *task_pgrp(struct task_struct *task) { return task->group_leader->pids[PIDTYPE_PGID].pid; Index: lx26-22-rc6-mm1/kernel/timer.c =================================================================== --- lx26-22-rc6-mm1.orig/kernel/timer.c 2007-07-05 18:53:42.000000000 -0700 +++ lx26-22-rc6-mm1/kernel/timer.c 2007-07-05 18:57:34.000000000 -0700 @@ -971,7 +971,7 @@ asmlinkage long sys_getppid(void) int pid; rcu_read_lock(); - pid = rcu_dereference(current->real_parent)->tgid; + pid = pid_to_nr(task_parent_tgid(current)); rcu_read_unlock(); return pid; Index: lx26-22-rc6-mm1/kernel/sys.c =================================================================== --- lx26-22-rc6-mm1.orig/kernel/sys.c 2007-07-05 18:53:42.000000000 -0700 +++ lx26-22-rc6-mm1/kernel/sys.c 2007-07-05 18:57:34.000000000 -0700 @@ -1503,7 +1503,7 @@ out: asmlinkage long sys_getpgid(pid_t pid) { if (!pid) - return process_group(current); + return pid_to_nr(task_pgrp(current)); else { int retval; struct task_struct *p; @@ -1515,7 +1515,7 @@ asmlinkage long sys_getpgid(pid_t pid) if (p) { retval = security_task_getpgid(p); if (!retval) - retval = process_group(p); + retval = pid_to_nr(task_pgrp(p)); } read_unlock(&tasklist_lock); return retval; @@ -1527,7 +1527,7 @@ asmlinkage long sys_getpgid(pid_t pid) asmlinkage long sys_getpgrp(void) { /* SMP - assuming writes are word atomic this is fine */ - return process_group(current); + return pid_to_nr(task_pgrp(current)); } #endif @@ -1535,7 +1535,7 @@ asmlinkage long sys_getpgrp(void) asmlinkage long sys_getsid(pid_t pid) { if (!pid) - return process_session(current); + return pid_to_nr(task_session(current)); else { int retval; struct task_struct *p; @@ -1547,7 +1547,7 @@ asmlinkage long sys_getsid(pid_t pid) if (p) { retval = security_task_getsid(p); if (!retval) - retval = process_session(p); + retval = pid_to_nr(task_session(p)); } read_unlock(&tasklist_lock); return retval; _______________________________________________ Containers mailing list Containers@lists.linux-foundation.org https://lists.linux-foundation.org/mailman/listinfo/containers