From 2ee0826085d1c0281cb60c1f4bc3e0c27efeedc3 Mon Sep 17 00:00:00 2001 From: Mike Rapoport Date: Tue, 6 Feb 2018 15:40:17 -0800 Subject: pids: introduce find_get_task_by_vpid() helper There are several functions that do find_task_by_vpid() followed by get_task_struct(). We can use a helper function instead. Link: http://lkml.kernel.org/r/1509602027-11337-1-git-send-email-rppt@linux.vnet.ibm.com Signed-off-by: Mike Rapoport Acked-by: Oleg Nesterov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/futex.c | 20 +------------------- kernel/pid.c | 13 +++++++++++++ kernel/ptrace.c | 27 ++++++--------------------- kernel/taskstats.c | 6 +----- 4 files changed, 21 insertions(+), 45 deletions(-) (limited to 'kernel') diff --git a/kernel/futex.c b/kernel/futex.c index 7f719d110908..1f450e092c74 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -862,24 +862,6 @@ static void put_pi_state(struct futex_pi_state *pi_state) } } -/* - * Look up the task based on what TID userspace gave us. - * We dont trust it. - */ -static struct task_struct *futex_find_get_task(pid_t pid) -{ - struct task_struct *p; - - rcu_read_lock(); - p = find_task_by_vpid(pid); - if (p) - get_task_struct(p); - - rcu_read_unlock(); - - return p; -} - #ifdef CONFIG_FUTEX_PI /* @@ -1183,7 +1165,7 @@ static int attach_to_pi_owner(u32 uval, union futex_key *key, */ if (!pid) return -ESRCH; - p = futex_find_get_task(pid); + p = find_get_task_by_vpid(pid); if (!p) return -ESRCH; diff --git a/kernel/pid.c b/kernel/pid.c index 5d30c87e3c42..ed6c343fe50d 100644 --- a/kernel/pid.c +++ b/kernel/pid.c @@ -343,6 +343,19 @@ struct task_struct *find_task_by_vpid(pid_t vnr) return find_task_by_pid_ns(vnr, task_active_pid_ns(current)); } +struct task_struct *find_get_task_by_vpid(pid_t nr) +{ + struct task_struct *task; + + rcu_read_lock(); + task = find_task_by_vpid(nr); + if (task) + get_task_struct(task); + rcu_read_unlock(); + + return task; +} + struct pid *get_task_pid(struct task_struct *task, enum pid_type type) { struct pid *pid; diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 5e1d713c8e61..21fec73d45d4 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -1103,21 +1103,6 @@ int ptrace_request(struct task_struct *child, long request, return ret; } -static struct task_struct *ptrace_get_task_struct(pid_t pid) -{ - struct task_struct *child; - - rcu_read_lock(); - child = find_task_by_vpid(pid); - if (child) - get_task_struct(child); - rcu_read_unlock(); - - if (!child) - return ERR_PTR(-ESRCH); - return child; -} - #ifndef arch_ptrace_attach #define arch_ptrace_attach(child) do { } while (0) #endif @@ -1135,9 +1120,9 @@ SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr, goto out; } - child = ptrace_get_task_struct(pid); - if (IS_ERR(child)) { - ret = PTR_ERR(child); + child = find_get_task_by_vpid(pid); + if (!child) { + ret = -ESRCH; goto out; } @@ -1281,9 +1266,9 @@ COMPAT_SYSCALL_DEFINE4(ptrace, compat_long_t, request, compat_long_t, pid, goto out; } - child = ptrace_get_task_struct(pid); - if (IS_ERR(child)) { - ret = PTR_ERR(child); + child = find_get_task_by_vpid(pid); + if (!child) { + ret = -ESRCH; goto out; } diff --git a/kernel/taskstats.c b/kernel/taskstats.c index 4559e914452b..4e62a4a8fa91 100644 --- a/kernel/taskstats.c +++ b/kernel/taskstats.c @@ -194,11 +194,7 @@ static int fill_stats_for_pid(pid_t pid, struct taskstats *stats) { struct task_struct *tsk; - rcu_read_lock(); - tsk = find_task_by_vpid(pid); - if (tsk) - get_task_struct(tsk); - rcu_read_unlock(); + tsk = find_get_task_by_vpid(pid); if (!tsk) return -ESRCH; fill_stats(current_user_ns(), task_active_pid_ns(current), tsk, stats); -- cgit v1.2.3