introduce "struct wait_opts" to simplify do_wait() patches
Introduce "struct wait_opts" which holds the parameters for misc helpers in do_wait() pathes. This adds 13 lines to kernel/exit.c, but saves 256 bytes from .o and imho makes the code much more readable. This patch temporary uglifies rusage/siginfo code a little bit, will be addressed by further cleanups. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Ingo Molnar <mingo@elte.hu> Acked-by: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Oleg Nesterov
Linus Torvalds
parent
47918025ef
commit
9e8ae01d1c
1 changed files with 110 additions and 97 deletions
207
kernel/exit.c
207
kernel/exit.c
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@ -1080,6 +1080,18 @@ SYSCALL_DEFINE1(exit_group, int, error_code)
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return 0;
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}
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struct wait_opts {
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enum pid_type wo_type;
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struct pid *wo_pid;
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int wo_flags;
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struct siginfo __user *wo_info;
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int __user *wo_stat;
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struct rusage __user *wo_rusage;
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int notask_error;
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};
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static struct pid *task_pid_type(struct task_struct *task, enum pid_type type)
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{
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struct pid *pid = NULL;
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@ -1090,13 +1102,12 @@ static struct pid *task_pid_type(struct task_struct *task, enum pid_type type)
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return pid;
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}
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static int eligible_child(enum pid_type type, struct pid *pid, int options,
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struct task_struct *p)
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static int eligible_child(struct wait_opts *wo, struct task_struct *p)
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{
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int err;
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if (type < PIDTYPE_MAX) {
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if (task_pid_type(p, type) != pid)
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if (wo->wo_type < PIDTYPE_MAX) {
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if (task_pid_type(p, wo->wo_type) != wo->wo_pid)
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return 0;
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}
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@ -1105,8 +1116,8 @@ static int eligible_child(enum pid_type type, struct pid *pid, int options,
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* set; otherwise, wait for non-clone children *only*. (Note:
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* A "clone" child here is one that reports to its parent
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* using a signal other than SIGCHLD.) */
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if (((p->exit_signal != SIGCHLD) ^ ((options & __WCLONE) != 0))
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&& !(options & __WALL))
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if (((p->exit_signal != SIGCHLD) ^ !!(wo->wo_flags & __WCLONE))
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&& !(wo->wo_flags & __WALL))
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return 0;
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err = security_task_wait(p);
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@ -1116,14 +1127,15 @@ static int eligible_child(enum pid_type type, struct pid *pid, int options,
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return 1;
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}
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static int wait_noreap_copyout(struct task_struct *p, pid_t pid, uid_t uid,
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int why, int status,
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struct siginfo __user *infop,
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struct rusage __user *rusagep)
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static int wait_noreap_copyout(struct wait_opts *wo, struct task_struct *p,
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pid_t pid, uid_t uid, int why, int status)
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{
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int retval = rusagep ? getrusage(p, RUSAGE_BOTH, rusagep) : 0;
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struct siginfo __user *infop;
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int retval = wo->wo_rusage
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? getrusage(p, RUSAGE_BOTH, wo->wo_rusage) : 0;
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put_task_struct(p);
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infop = wo->wo_info;
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if (!retval)
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retval = put_user(SIGCHLD, &infop->si_signo);
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if (!retval)
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@ -1147,19 +1159,18 @@ static int wait_noreap_copyout(struct task_struct *p, pid_t pid, uid_t uid,
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* the lock and this task is uninteresting. If we return nonzero, we have
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* released the lock and the system call should return.
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*/
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static int wait_task_zombie(struct task_struct *p, int options,
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struct siginfo __user *infop,
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int __user *stat_addr, struct rusage __user *ru)
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static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p)
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{
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unsigned long state;
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int retval, status, traced;
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pid_t pid = task_pid_vnr(p);
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uid_t uid = __task_cred(p)->uid;
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struct siginfo __user *infop;
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if (!likely(options & WEXITED))
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if (!likely(wo->wo_flags & WEXITED))
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return 0;
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if (unlikely(options & WNOWAIT)) {
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if (unlikely(wo->wo_flags & WNOWAIT)) {
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int exit_code = p->exit_code;
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int why, status;
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@ -1172,8 +1183,7 @@ static int wait_task_zombie(struct task_struct *p, int options,
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why = (exit_code & 0x80) ? CLD_DUMPED : CLD_KILLED;
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status = exit_code & 0x7f;
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}
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return wait_noreap_copyout(p, pid, uid, why,
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status, infop, ru);
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return wait_noreap_copyout(wo, p, pid, uid, why, status);
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}
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/*
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@ -1250,11 +1260,14 @@ static int wait_task_zombie(struct task_struct *p, int options,
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*/
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read_unlock(&tasklist_lock);
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retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
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retval = wo->wo_rusage
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? getrusage(p, RUSAGE_BOTH, wo->wo_rusage) : 0;
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status = (p->signal->flags & SIGNAL_GROUP_EXIT)
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? p->signal->group_exit_code : p->exit_code;
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if (!retval && stat_addr)
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retval = put_user(status, stat_addr);
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if (!retval && wo->wo_stat)
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retval = put_user(status, wo->wo_stat);
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infop = wo->wo_info;
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if (!retval && infop)
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retval = put_user(SIGCHLD, &infop->si_signo);
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if (!retval && infop)
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@ -1322,10 +1335,10 @@ static int *task_stopped_code(struct task_struct *p, bool ptrace)
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* the lock and this task is uninteresting. If we return nonzero, we have
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* released the lock and the system call should return.
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*/
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static int wait_task_stopped(int ptrace, struct task_struct *p,
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int options, struct siginfo __user *infop,
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int __user *stat_addr, struct rusage __user *ru)
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static int wait_task_stopped(struct wait_opts *wo,
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int ptrace, struct task_struct *p)
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{
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struct siginfo __user *infop;
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int retval, exit_code, *p_code, why;
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uid_t uid = 0; /* unneeded, required by compiler */
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pid_t pid;
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@ -1333,7 +1346,7 @@ static int wait_task_stopped(int ptrace, struct task_struct *p,
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/*
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* Traditionally we see ptrace'd stopped tasks regardless of options.
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*/
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if (!ptrace && !(options & WUNTRACED))
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if (!ptrace && !(wo->wo_flags & WUNTRACED))
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return 0;
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exit_code = 0;
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@ -1347,7 +1360,7 @@ static int wait_task_stopped(int ptrace, struct task_struct *p,
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if (!exit_code)
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goto unlock_sig;
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if (!unlikely(options & WNOWAIT))
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if (!unlikely(wo->wo_flags & WNOWAIT))
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*p_code = 0;
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/* don't need the RCU readlock here as we're holding a spinlock */
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@ -1369,14 +1382,15 @@ static int wait_task_stopped(int ptrace, struct task_struct *p,
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why = ptrace ? CLD_TRAPPED : CLD_STOPPED;
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read_unlock(&tasklist_lock);
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if (unlikely(options & WNOWAIT))
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return wait_noreap_copyout(p, pid, uid,
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why, exit_code,
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infop, ru);
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if (unlikely(wo->wo_flags & WNOWAIT))
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return wait_noreap_copyout(wo, p, pid, uid, why, exit_code);
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retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
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if (!retval && stat_addr)
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retval = put_user((exit_code << 8) | 0x7f, stat_addr);
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retval = wo->wo_rusage
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? getrusage(p, RUSAGE_BOTH, wo->wo_rusage) : 0;
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if (!retval && wo->wo_stat)
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retval = put_user((exit_code << 8) | 0x7f, wo->wo_stat);
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infop = wo->wo_info;
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if (!retval && infop)
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retval = put_user(SIGCHLD, &infop->si_signo);
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if (!retval && infop)
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@ -1403,15 +1417,13 @@ static int wait_task_stopped(int ptrace, struct task_struct *p,
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* the lock and this task is uninteresting. If we return nonzero, we have
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* released the lock and the system call should return.
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*/
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static int wait_task_continued(struct task_struct *p, int options,
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struct siginfo __user *infop,
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int __user *stat_addr, struct rusage __user *ru)
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static int wait_task_continued(struct wait_opts *wo, struct task_struct *p)
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{
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int retval;
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pid_t pid;
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uid_t uid;
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if (!unlikely(options & WCONTINUED))
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if (!unlikely(wo->wo_flags & WCONTINUED))
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return 0;
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if (!(p->signal->flags & SIGNAL_STOP_CONTINUED))
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@ -1423,7 +1435,7 @@ static int wait_task_continued(struct task_struct *p, int options,
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spin_unlock_irq(&p->sighand->siglock);
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return 0;
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}
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if (!unlikely(options & WNOWAIT))
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if (!unlikely(wo->wo_flags & WNOWAIT))
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p->signal->flags &= ~SIGNAL_STOP_CONTINUED;
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uid = __task_cred(p)->uid;
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spin_unlock_irq(&p->sighand->siglock);
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@ -1432,17 +1444,17 @@ static int wait_task_continued(struct task_struct *p, int options,
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get_task_struct(p);
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read_unlock(&tasklist_lock);
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if (!infop) {
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retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
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if (!wo->wo_info) {
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retval = wo->wo_rusage
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? getrusage(p, RUSAGE_BOTH, wo->wo_rusage) : 0;
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put_task_struct(p);
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if (!retval && stat_addr)
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retval = put_user(0xffff, stat_addr);
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if (!retval && wo->wo_stat)
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retval = put_user(0xffff, wo->wo_stat);
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if (!retval)
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retval = pid;
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} else {
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retval = wait_noreap_copyout(p, pid, uid,
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CLD_CONTINUED, SIGCONT,
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infop, ru);
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retval = wait_noreap_copyout(wo, p, pid, uid,
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CLD_CONTINUED, SIGCONT);
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BUG_ON(retval == 0);
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}
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@ -1452,19 +1464,16 @@ static int wait_task_continued(struct task_struct *p, int options,
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/*
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* Consider @p for a wait by @parent.
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*
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* -ECHILD should be in *@notask_error before the first call.
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* -ECHILD should be in ->notask_error before the first call.
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* Returns nonzero for a final return, when we have unlocked tasklist_lock.
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* Returns zero if the search for a child should continue;
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* then *@notask_error is 0 if @p is an eligible child,
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* then ->notask_error is 0 if @p is an eligible child,
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* or another error from security_task_wait(), or still -ECHILD.
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*/
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static int wait_consider_task(struct task_struct *parent, int ptrace,
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struct task_struct *p, int *notask_error,
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enum pid_type type, struct pid *pid, int options,
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struct siginfo __user *infop,
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int __user *stat_addr, struct rusage __user *ru)
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static int wait_consider_task(struct wait_opts *wo, struct task_struct *parent,
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int ptrace, struct task_struct *p)
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{
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int ret = eligible_child(type, pid, options, p);
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int ret = eligible_child(wo, p);
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if (!ret)
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return ret;
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@ -1476,8 +1485,8 @@ static int wait_consider_task(struct task_struct *parent, int ptrace,
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* to look for security policy problems, rather
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* than for mysterious wait bugs.
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*/
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if (*notask_error)
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*notask_error = ret;
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if (wo->notask_error)
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wo->notask_error = ret;
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return 0;
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}
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@ -1486,7 +1495,7 @@ static int wait_consider_task(struct task_struct *parent, int ptrace,
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* This child is hidden by ptrace.
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* We aren't allowed to see it now, but eventually we will.
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*/
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*notask_error = 0;
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wo->notask_error = 0;
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return 0;
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}
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@ -1497,34 +1506,30 @@ static int wait_consider_task(struct task_struct *parent, int ptrace,
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* We don't reap group leaders with subthreads.
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*/
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if (p->exit_state == EXIT_ZOMBIE && !delay_group_leader(p))
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return wait_task_zombie(p, options, infop, stat_addr, ru);
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return wait_task_zombie(wo, p);
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/*
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* It's stopped or running now, so it might
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* later continue, exit, or stop again.
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*/
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*notask_error = 0;
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wo->notask_error = 0;
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if (task_stopped_code(p, ptrace))
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return wait_task_stopped(ptrace, p, options,
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infop, stat_addr, ru);
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return wait_task_stopped(wo, ptrace, p);
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return wait_task_continued(p, options, infop, stat_addr, ru);
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return wait_task_continued(wo, p);
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}
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/*
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* Do the work of do_wait() for one thread in the group, @tsk.
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*
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* -ECHILD should be in *@notask_error before the first call.
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* -ECHILD should be in ->notask_error before the first call.
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* Returns nonzero for a final return, when we have unlocked tasklist_lock.
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* Returns zero if the search for a child should continue; then
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* *@notask_error is 0 if there were any eligible children,
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* ->notask_error is 0 if there were any eligible children,
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* or another error from security_task_wait(), or still -ECHILD.
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*/
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static int do_wait_thread(struct task_struct *tsk, int *notask_error,
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enum pid_type type, struct pid *pid, int options,
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struct siginfo __user *infop, int __user *stat_addr,
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struct rusage __user *ru)
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static int do_wait_thread(struct wait_opts *wo, struct task_struct *tsk)
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{
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struct task_struct *p;
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@ -1533,9 +1538,7 @@ static int do_wait_thread(struct task_struct *tsk, int *notask_error,
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* Do not consider detached threads.
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*/
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if (!task_detached(p)) {
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int ret = wait_consider_task(tsk, 0, p, notask_error,
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type, pid, options,
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infop, stat_addr, ru);
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int ret = wait_consider_task(wo, tsk, 0, p);
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if (ret)
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return ret;
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}
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@ -1544,17 +1547,12 @@ static int do_wait_thread(struct task_struct *tsk, int *notask_error,
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return 0;
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}
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static int ptrace_do_wait(struct task_struct *tsk, int *notask_error,
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enum pid_type type, struct pid *pid, int options,
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struct siginfo __user *infop, int __user *stat_addr,
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struct rusage __user *ru)
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static int ptrace_do_wait(struct wait_opts *wo, struct task_struct *tsk)
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{
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struct task_struct *p;
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list_for_each_entry(p, &tsk->ptraced, ptrace_entry) {
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int ret = wait_consider_task(tsk, 1, p, notask_error,
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type, pid, options,
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infop, stat_addr, ru);
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int ret = wait_consider_task(wo, tsk, 1, p);
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if (ret)
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return ret;
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}
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@ -1562,38 +1560,36 @@ static int ptrace_do_wait(struct task_struct *tsk, int *notask_error,
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return 0;
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}
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static long do_wait(enum pid_type type, struct pid *pid, int options,
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struct siginfo __user *infop, int __user *stat_addr,
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struct rusage __user *ru)
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static long do_wait(struct wait_opts *wo)
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{
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DECLARE_WAITQUEUE(wait, current);
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struct task_struct *tsk;
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int retval;
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trace_sched_process_wait(pid);
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trace_sched_process_wait(wo->wo_pid);
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add_wait_queue(¤t->signal->wait_chldexit,&wait);
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repeat:
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/*
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* If there is nothing that can match our critiera just get out.
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* We will clear @retval to zero if we see any child that might later
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* match our criteria, even if we are not able to reap it yet.
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* We will clear ->notask_error to zero if we see any child that
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* might later match our criteria, even if we are not able to reap
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* it yet.
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*/
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retval = -ECHILD;
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if ((type < PIDTYPE_MAX) && (!pid || hlist_empty(&pid->tasks[type])))
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retval = wo->notask_error = -ECHILD;
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if ((wo->wo_type < PIDTYPE_MAX) &&
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(!wo->wo_pid || hlist_empty(&wo->wo_pid->tasks[wo->wo_type])))
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goto end;
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current->state = TASK_INTERRUPTIBLE;
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read_lock(&tasklist_lock);
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tsk = current;
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do {
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int tsk_result = do_wait_thread(tsk, &retval,
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type, pid, options,
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infop, stat_addr, ru);
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int tsk_result = do_wait_thread(wo, tsk);
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if (!tsk_result)
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tsk_result = ptrace_do_wait(tsk, &retval,
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type, pid, options,
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infop, stat_addr, ru);
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tsk_result = ptrace_do_wait(wo, tsk);
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if (tsk_result) {
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/*
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* tasklist_lock is unlocked and we have a final result.
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@ -1602,25 +1598,27 @@ static long do_wait(enum pid_type type, struct pid *pid, int options,
|
|||
goto end;
|
||||
}
|
||||
|
||||
if (options & __WNOTHREAD)
|
||||
if (wo->wo_flags & __WNOTHREAD)
|
||||
break;
|
||||
tsk = next_thread(tsk);
|
||||
BUG_ON(tsk->signal != current->signal);
|
||||
} while (tsk != current);
|
||||
read_unlock(&tasklist_lock);
|
||||
|
||||
if (!retval && !(options & WNOHANG)) {
|
||||
retval = wo->notask_error;
|
||||
if (!retval && !(wo->wo_flags & WNOHANG)) {
|
||||
retval = -ERESTARTSYS;
|
||||
if (!signal_pending(current)) {
|
||||
schedule();
|
||||
goto repeat;
|
||||
}
|
||||
}
|
||||
|
||||
end:
|
||||
current->state = TASK_RUNNING;
|
||||
remove_wait_queue(¤t->signal->wait_chldexit,&wait);
|
||||
if (infop) {
|
||||
if (wo->wo_info) {
|
||||
struct siginfo __user *infop = wo->wo_info;
|
||||
|
||||
if (retval > 0)
|
||||
retval = 0;
|
||||
else {
|
||||
|
|
@ -1649,6 +1647,7 @@ static long do_wait(enum pid_type type, struct pid *pid, int options,
|
|||
SYSCALL_DEFINE5(waitid, int, which, pid_t, upid, struct siginfo __user *,
|
||||
infop, int, options, struct rusage __user *, ru)
|
||||
{
|
||||
struct wait_opts wo;
|
||||
struct pid *pid = NULL;
|
||||
enum pid_type type;
|
||||
long ret;
|
||||
|
|
@ -1678,7 +1677,14 @@ SYSCALL_DEFINE5(waitid, int, which, pid_t, upid, struct siginfo __user *,
|
|||
|
||||
if (type < PIDTYPE_MAX)
|
||||
pid = find_get_pid(upid);
|
||||
ret = do_wait(type, pid, options, infop, NULL, ru);
|
||||
|
||||
wo.wo_type = type;
|
||||
wo.wo_pid = pid;
|
||||
wo.wo_flags = options;
|
||||
wo.wo_info = infop;
|
||||
wo.wo_stat = NULL;
|
||||
wo.wo_rusage = ru;
|
||||
ret = do_wait(&wo);
|
||||
put_pid(pid);
|
||||
|
||||
/* avoid REGPARM breakage on x86: */
|
||||
|
|
@ -1689,6 +1695,7 @@ SYSCALL_DEFINE5(waitid, int, which, pid_t, upid, struct siginfo __user *,
|
|||
SYSCALL_DEFINE4(wait4, pid_t, upid, int __user *, stat_addr,
|
||||
int, options, struct rusage __user *, ru)
|
||||
{
|
||||
struct wait_opts wo;
|
||||
struct pid *pid = NULL;
|
||||
enum pid_type type;
|
||||
long ret;
|
||||
|
|
@ -1710,7 +1717,13 @@ SYSCALL_DEFINE4(wait4, pid_t, upid, int __user *, stat_addr,
|
|||
pid = find_get_pid(upid);
|
||||
}
|
||||
|
||||
ret = do_wait(type, pid, options | WEXITED, NULL, stat_addr, ru);
|
||||
wo.wo_type = type;
|
||||
wo.wo_pid = pid;
|
||||
wo.wo_flags = options | WEXITED;
|
||||
wo.wo_info = NULL;
|
||||
wo.wo_stat = stat_addr;
|
||||
wo.wo_rusage = ru;
|
||||
ret = do_wait(&wo);
|
||||
put_pid(pid);
|
||||
|
||||
/* avoid REGPARM breakage on x86: */
|
||||
|
|
|
|||
Loading…
Reference in a new issue