From b8fceee17a310f189188599a8fa5e9beaff57eb0 Mon Sep 17 00:00:00 2001 From: Davide Libenzi Date: Thu, 20 Sep 2007 12:40:16 -0700 Subject: signalfd simplification This simplifies signalfd code, by avoiding it to remain attached to the sighand during its lifetime. In this way, the signalfd remain attached to the sighand only during poll(2) (and select and epoll) and read(2). This also allows to remove all the custom "tsk == current" checks in kernel/signal.c, since dequeue_signal() will only be called by "current". I think this is also what Ben was suggesting time ago. The external effect of this, is that a thread can extract only its own private signals and the group ones. I think this is an acceptable behaviour, in that those are the signals the thread would be able to fetch w/out signalfd. Signed-off-by: Davide Libenzi Signed-off-by: Linus Torvalds --- kernel/exit.c | 9 --------- kernel/fork.c | 2 +- kernel/signal.c | 8 +++----- 3 files changed, 4 insertions(+), 15 deletions(-) (limited to 'kernel') diff --git a/kernel/exit.c b/kernel/exit.c index 06b24b3aa37..993369ee94d 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -24,7 +24,6 @@ #include #include #include -#include #include #include #include @@ -86,14 +85,6 @@ static void __exit_signal(struct task_struct *tsk) sighand = rcu_dereference(tsk->sighand); spin_lock(&sighand->siglock); - /* - * Notify that this sighand has been detached. This must - * be called with the tsk->sighand lock held. Also, this - * access tsk->sighand internally, so it must be called - * before tsk->sighand is reset. - */ - signalfd_detach_locked(tsk); - posix_cpu_timers_exit(tsk); if (atomic_dec_and_test(&sig->count)) posix_cpu_timers_exit_group(tsk); diff --git a/kernel/fork.c b/kernel/fork.c index 7332e236d36..33f12f48684 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1438,7 +1438,7 @@ static void sighand_ctor(void *data, struct kmem_cache *cachep, struct sighand_struct *sighand = data; spin_lock_init(&sighand->siglock); - INIT_LIST_HEAD(&sighand->signalfd_list); + init_waitqueue_head(&sighand->signalfd_wqh); } void __init proc_caches_init(void) diff --git a/kernel/signal.c b/kernel/signal.c index 3169bed0b4d..9fb91a32edd 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -378,8 +378,7 @@ int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info) /* We only dequeue private signals from ourselves, we don't let * signalfd steal them */ - if (likely(tsk == current)) - signr = __dequeue_signal(&tsk->pending, mask, info); + signr = __dequeue_signal(&tsk->pending, mask, info); if (!signr) { signr = __dequeue_signal(&tsk->signal->shared_pending, mask, info); @@ -407,8 +406,7 @@ int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info) } } } - if (likely(tsk == current)) - recalc_sigpending(); + recalc_sigpending(); if (signr && unlikely(sig_kernel_stop(signr))) { /* * Set a marker that we have dequeued a stop signal. Our @@ -425,7 +423,7 @@ int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info) if (!(tsk->signal->flags & SIGNAL_GROUP_EXIT)) tsk->signal->flags |= SIGNAL_STOP_DEQUEUED; } - if (signr && likely(tsk == current) && + if (signr && ((info->si_code & __SI_MASK) == __SI_TIMER) && info->si_sys_private){ /* -- cgit v1.2.3