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 <rppt@linux.vnet.ibm.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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@ -2610,17 +2610,10 @@ pfm_get_task(pfm_context_t *ctx, pid_t pid, struct task_struct **task)
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if (pid < 2) return -EPERM;
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if (pid != task_pid_vnr(current)) {
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read_lock(&tasklist_lock);
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p = find_task_by_vpid(pid);
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/* make sure task cannot go away while we operate on it */
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if (p) get_task_struct(p);
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read_unlock(&tasklist_lock);
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if (p == NULL) return -ESRCH;
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p = find_get_task_by_vpid(pid);
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if (!p)
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return -ESRCH;
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}
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ret = pfm_task_incompatible(ctx, p);
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@ -1489,6 +1489,11 @@ static inline struct thread_info *task_thread_info(struct task_struct *task)
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extern struct task_struct *find_task_by_vpid(pid_t nr);
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extern struct task_struct *find_task_by_pid_ns(pid_t nr, struct pid_namespace *ns);
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/*
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* find a task by its virtual pid and get the task struct
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*/
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extern struct task_struct *find_get_task_by_vpid(pid_t nr);
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extern int wake_up_state(struct task_struct *tsk, unsigned int state);
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extern int wake_up_process(struct task_struct *tsk);
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extern void wake_up_new_task(struct task_struct *tsk);
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@ -862,24 +862,6 @@ static void put_pi_state(struct futex_pi_state *pi_state)
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}
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}
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/*
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* Look up the task based on what TID userspace gave us.
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* We dont trust it.
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*/
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static struct task_struct *futex_find_get_task(pid_t pid)
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{
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struct task_struct *p;
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rcu_read_lock();
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p = find_task_by_vpid(pid);
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if (p)
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get_task_struct(p);
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rcu_read_unlock();
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return p;
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}
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#ifdef CONFIG_FUTEX_PI
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/*
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@ -1183,7 +1165,7 @@ static int attach_to_pi_owner(u32 uval, union futex_key *key,
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*/
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if (!pid)
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return -ESRCH;
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p = futex_find_get_task(pid);
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p = find_get_task_by_vpid(pid);
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if (!p)
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return -ESRCH;
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13
kernel/pid.c
13
kernel/pid.c
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@ -343,6 +343,19 @@ struct task_struct *find_task_by_vpid(pid_t vnr)
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return find_task_by_pid_ns(vnr, task_active_pid_ns(current));
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}
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struct task_struct *find_get_task_by_vpid(pid_t nr)
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{
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struct task_struct *task;
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rcu_read_lock();
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task = find_task_by_vpid(nr);
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if (task)
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get_task_struct(task);
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rcu_read_unlock();
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return task;
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}
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struct pid *get_task_pid(struct task_struct *task, enum pid_type type)
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{
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struct pid *pid;
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@ -1103,21 +1103,6 @@ int ptrace_request(struct task_struct *child, long request,
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return ret;
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}
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static struct task_struct *ptrace_get_task_struct(pid_t pid)
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{
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struct task_struct *child;
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rcu_read_lock();
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child = find_task_by_vpid(pid);
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if (child)
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get_task_struct(child);
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rcu_read_unlock();
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if (!child)
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return ERR_PTR(-ESRCH);
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return child;
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}
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#ifndef arch_ptrace_attach
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#define arch_ptrace_attach(child) do { } while (0)
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#endif
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@ -1135,9 +1120,9 @@ SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr,
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goto out;
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}
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child = ptrace_get_task_struct(pid);
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if (IS_ERR(child)) {
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ret = PTR_ERR(child);
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child = find_get_task_by_vpid(pid);
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if (!child) {
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ret = -ESRCH;
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goto out;
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}
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@ -1281,9 +1266,9 @@ COMPAT_SYSCALL_DEFINE4(ptrace, compat_long_t, request, compat_long_t, pid,
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goto out;
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}
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child = ptrace_get_task_struct(pid);
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if (IS_ERR(child)) {
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ret = PTR_ERR(child);
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child = find_get_task_by_vpid(pid);
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if (!child) {
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ret = -ESRCH;
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goto out;
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}
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@ -194,11 +194,7 @@ static int fill_stats_for_pid(pid_t pid, struct taskstats *stats)
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{
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struct task_struct *tsk;
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rcu_read_lock();
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tsk = find_task_by_vpid(pid);
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if (tsk)
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get_task_struct(tsk);
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rcu_read_unlock();
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tsk = find_get_task_by_vpid(pid);
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if (!tsk)
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return -ESRCH;
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fill_stats(current_user_ns(), task_active_pid_ns(current), tsk, stats);
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@ -197,11 +197,7 @@ static ssize_t process_vm_rw_core(pid_t pid, struct iov_iter *iter,
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}
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/* Get process information */
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rcu_read_lock();
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task = find_task_by_vpid(pid);
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if (task)
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get_task_struct(task);
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rcu_read_unlock();
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task = find_get_task_by_vpid(pid);
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if (!task) {
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rc = -ESRCH;
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goto free_proc_pages;
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@ -250,15 +250,10 @@ int yama_task_prctl(int option, unsigned long arg2, unsigned long arg3,
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} else {
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struct task_struct *tracer;
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rcu_read_lock();
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tracer = find_task_by_vpid(arg2);
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if (tracer)
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get_task_struct(tracer);
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else
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tracer = find_get_task_by_vpid(arg2);
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if (!tracer) {
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rc = -EINVAL;
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rcu_read_unlock();
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if (tracer) {
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} else {
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rc = yama_ptracer_add(tracer, myself);
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put_task_struct(tracer);
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}
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