Split up "struct signal_struct" into "signal" and "sighand" parts.

This is required to get make the old LinuxThread semantics work
together with the fixed-for-POSIX full signal sharing. A traditional
CLONE_SIGHAND thread (LinuxThread) will not see any other shared
signal state, while a new-style CLONE_THREAD thread will share all
of it.

This way the two methods don't confuse each other.

arch/i386/kernel/init_task.c

@@ -11,6 +11,7 @@
 static struct fs_struct init_fs = INIT_FS;
 static struct files_struct init_files = INIT_FILES;
 static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
+static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
 struct mm_struct init_mm = INIT_MM(init_mm);
 
 /*

arch/i386/kernel/signal.c

@@ -37,11 +37,11 @@ sys_sigsuspend(int history0, int history1, old_sigset_t mask)
 	sigset_t saveset;
 
 	mask &= _BLOCKABLE;
-	spin_lock_irq(&current->sig->siglock);
+	spin_lock_irq(&current->sighand->siglock);
 	saveset = current->blocked;
 	siginitset(&current->blocked, mask);
 	recalc_sigpending();
-	spin_unlock_irq(&current->sig->siglock);
+	spin_unlock_irq(&current->sighand->siglock);
 
 	regs->eax = -EINTR;
 	while (1) {
@@ -66,11 +66,11 @@ sys_rt_sigsuspend(sigset_t *unewset, size_t sigsetsize)
 		return -EFAULT;
 	sigdelsetmask(&newset, ~_BLOCKABLE);
 
-	spin_lock_irq(&current->sig->siglock);
+	spin_lock_irq(&current->sighand->siglock);
 	saveset = current->blocked;
 	current->blocked = newset;
 	recalc_sigpending();
-	spin_unlock_irq(&current->sig->siglock);
+	spin_unlock_irq(&current->sighand->siglock);
 
 	regs->eax = -EINTR;
 	while (1) {
@@ -224,10 +224,10 @@ asmlinkage int sys_sigreturn(unsigned long __unused)
 		goto badframe;
 
 	sigdelsetmask(&set, ~_BLOCKABLE);
-	spin_lock_irq(&current->sig->siglock);
+	spin_lock_irq(&current->sighand->siglock);
 	current->blocked = set;
 	recalc_sigpending();
-	spin_unlock_irq(&current->sig->siglock);
+	spin_unlock_irq(&current->sighand->siglock);
 	
 	if (restore_sigcontext(regs, &frame->sc, &eax))
 		goto badframe;
@@ -252,10 +252,10 @@ asmlinkage int sys_rt_sigreturn(unsigned long __unused)
 		goto badframe;
 
 	sigdelsetmask(&set, ~_BLOCKABLE);
-	spin_lock_irq(&current->sig->siglock);
+	spin_lock_irq(&current->sighand->siglock);
 	current->blocked = set;
 	recalc_sigpending();
-	spin_unlock_irq(&current->sig->siglock);
+	spin_unlock_irq(&current->sighand->siglock);
 	
 	if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &eax))
 		goto badframe;
@@ -513,7 +513,7 @@ static void
 handle_signal(unsigned long sig, siginfo_t *info, sigset_t *oldset,
 	struct pt_regs * regs)
 {
-	struct k_sigaction *ka = &current->sig->action[sig-1];
+	struct k_sigaction *ka = &current->sighand->action[sig-1];
 
 	/* Are we from a system call? */
 	if (regs->orig_eax >= 0) {
@@ -547,11 +547,11 @@ handle_signal(unsigned long sig, siginfo_t *info, sigset_t *oldset,
 		ka->sa.sa_handler = SIG_DFL;
 
 	if (!(ka->sa.sa_flags & SA_NODEFER)) {
-		spin_lock_irq(&current->sig->siglock);
+		spin_lock_irq(&current->sighand->siglock);
 		sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
 		sigaddset(&current->blocked,sig);
 		recalc_sigpending();
-		spin_unlock_irq(&current->sig->siglock);
+		spin_unlock_irq(&current->sighand->siglock);
 	}
 }
 

arch/i386/kernel/vm86.c

@@ -512,10 +512,10 @@ int handle_vm86_trap(struct kernel_vm86_regs * regs, long error_code, int trapno
 		return 1; /* we let this handle by the calling routine */
 	if (current->ptrace & PT_PTRACED) {
 		unsigned long flags;
-		spin_lock_irqsave(&current->sig->siglock, flags);
+		spin_lock_irqsave(&current->sighand->siglock, flags);
 		sigdelset(&current->blocked, SIGTRAP);
 		recalc_sigpending();
-		spin_unlock_irqrestore(&current->sig->siglock, flags);
+		spin_unlock_irqrestore(&current->sighand->siglock, flags);
 	}
 	send_sig(SIGTRAP, current, 1);
 	current->thread.trap_no = trapno;

drivers/block/loop.c

@@ -584,10 +584,10 @@ static int loop_thread(void *data)
 					   hence, it mustn't be stopped at all because it could
 					   be indirectly used during suspension */
 
-	spin_lock_irq(&current->sig->siglock);
+	spin_lock_irq(&current->sighand->siglock);
 	sigfillset(&current->blocked);
 	flush_signals(current);
-	spin_unlock_irq(&current->sig->siglock);
+	spin_unlock_irq(&current->sighand->siglock);
 
 	set_user_nice(current, -20);
 

drivers/char/n_tty.c

@@ -787,7 +787,7 @@ static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp,
 int is_ignored(int sig)
 {
 	return (sigismember(&current->blocked, sig) ||
-	        current->sig->action[sig-1].sa.sa_handler == SIG_IGN);
+	        current->sighand->action[sig-1].sa.sa_handler == SIG_IGN);
 }
 
 static void n_tty_set_termios(struct tty_struct *tty, struct termios * old)

drivers/scsi/scsi_error.c

@@ -1575,10 +1575,10 @@ void scsi_error_handler(void *data)
 	int rtn;
 	DECLARE_MUTEX_LOCKED(sem);
 
-	spin_lock_irq(&current->sig->siglock);
+	spin_lock_irq(&current->sighand->siglock);
 	sigfillset(&current->blocked);
 	recalc_sigpending();
-	spin_unlock_irq(&current->sig->siglock);
+	spin_unlock_irq(&current->sighand->siglock);
 
 	lock_kernel();
 

drivers/usb/storage/usb.c

@@ -301,12 +301,12 @@ static int usb_stor_control_thread(void * __us)
 	daemonize();
 
 	/* avoid getting signals */
-	spin_lock_irq(&current->sig->siglock);
+	spin_lock_irq(&current->sighand->siglock);
 	flush_signals(current);
 	current->flags |= PF_IOTHREAD;
 	sigfillset(&current->blocked);
 	recalc_sigpending();
-	spin_unlock_irq(&current->sig->siglock);
+	spin_unlock_irq(&current->sighand->siglock);
 
 	/* set our name for identification purposes */
 	sprintf(current->comm, "usb-storage");

fs/autofs/waitq.c

@@ -70,10 +70,10 @@ static int autofs_write(struct file *file, const void *addr, int bytes)
 	/* Keep the currently executing process from receiving a
 	   SIGPIPE unless it was already supposed to get one */
 	if (wr == -EPIPE && !sigpipe) {
-		spin_lock_irqsave(&current->sig->siglock, flags);
+		spin_lock_irqsave(&current->sighand->siglock, flags);
 		sigdelset(&current->pending.signal, SIGPIPE);
 		recalc_sigpending();
-		spin_unlock_irqrestore(&current->sig->siglock, flags);
+		spin_unlock_irqrestore(&current->sighand->siglock, flags);
 	}
 
 	return (bytes > 0);
@@ -161,18 +161,18 @@ int autofs_wait(struct autofs_sb_info *sbi, struct qstr *name)
 		sigset_t oldset;
 		unsigned long irqflags;
 
-		spin_lock_irqsave(&current->sig->siglock, irqflags);
+		spin_lock_irqsave(&current->sighand->siglock, irqflags);
 		oldset = current->blocked;
 		siginitsetinv(&current->blocked, SHUTDOWN_SIGS & ~oldset.sig[0]);
 		recalc_sigpending();
-		spin_unlock_irqrestore(&current->sig->siglock, irqflags);
+		spin_unlock_irqrestore(&current->sighand->siglock, irqflags);
 
 		interruptible_sleep_on(&wq->queue);
 
-		spin_lock_irqsave(&current->sig->siglock, irqflags);
+		spin_lock_irqsave(&current->sighand->siglock, irqflags);
 		current->blocked = oldset;
 		recalc_sigpending();
-		spin_unlock_irqrestore(&current->sig->siglock, irqflags);
+		spin_unlock_irqrestore(&current->sighand->siglock, irqflags);
 	} else {
 		DPRINTK(("autofs_wait: skipped sleeping\n"));
 	}

fs/autofs4/waitq.c

@@ -74,10 +74,10 @@ static int autofs4_write(struct file *file, const void *addr, int bytes)
 	/* Keep the currently executing process from receiving a
 	   SIGPIPE unless it was already supposed to get one */
 	if (wr == -EPIPE && !sigpipe) {
-		spin_lock_irqsave(&current->sig->siglock, flags);
+		spin_lock_irqsave(&current->sighand->siglock, flags);
 		sigdelset(&current->pending.signal, SIGPIPE);
 		recalc_sigpending();
-		spin_unlock_irqrestore(&current->sig->siglock, flags);
+		spin_unlock_irqrestore(&current->sighand->siglock, flags);
 	}
 
 	return (bytes > 0);
@@ -198,18 +198,18 @@ int autofs4_wait(struct autofs_sb_info *sbi, struct qstr *name,
 		sigset_t oldset;
 		unsigned long irqflags;
 
-		spin_lock_irqsave(&current->sig->siglock, irqflags);
+		spin_lock_irqsave(&current->sighand->siglock, irqflags);
 		oldset = current->blocked;
 		siginitsetinv(&current->blocked, SHUTDOWN_SIGS & ~oldset.sig[0]);
 		recalc_sigpending();
-		spin_unlock_irqrestore(&current->sig->siglock, irqflags);
+		spin_unlock_irqrestore(&current->sighand->siglock, irqflags);
 
 		interruptible_sleep_on(&wq->queue);
 
-		spin_lock_irqsave(&current->sig->siglock, irqflags);
+		spin_lock_irqsave(&current->sighand->siglock, irqflags);
 		current->blocked = oldset;
 		recalc_sigpending();
-		spin_unlock_irqrestore(&current->sig->siglock, irqflags);
+		spin_unlock_irqrestore(&current->sighand->siglock, irqflags);
 	} else {
 		DPRINTK(("autofs_wait: skipped sleeping\n"));
 	}

fs/exec.c

@@ -559,31 +559,61 @@ static inline void put_proc_dentry(struct dentry *dentry)
  * disturbing other processes.  (Other processes might share the signal
  * table via the CLONE_SIGHAND option to clone().)
  */
-static inline int de_thread(struct signal_struct *oldsig)
+static inline int de_thread(struct task_struct *tsk)
 {
-	struct signal_struct *newsig;
+	struct signal_struct *newsig, *oldsig = tsk->signal;
+	struct sighand_struct *newsighand, *oldsighand = tsk->sighand;
+	spinlock_t *lock = &oldsighand->siglock;
 	int count;
 
-	if (atomic_read(&current->sig->count) <= 1)
+	/*
+	 * If we don't share sighandlers, then we aren't sharing anything
+	 * and we can just re-use it all.
+	 */
+	if (atomic_read(&oldsighand->count) <= 1)
 		return 0;
 
-	newsig = kmem_cache_alloc(sigact_cachep, GFP_KERNEL);
-	if (!newsig)
+	newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL);
+	if (!newsighand)
+		return -ENOMEM;
+
+	spin_lock_init(&newsighand->siglock);
+	atomic_set(&newsighand->count, 1);
+	memcpy(newsighand->action, oldsighand->action, sizeof(newsighand->action));
+
+	/*
+	 * See if we need to allocate a new signal structure
+	 */
+	newsig = NULL;
+	if (atomic_read(&oldsig->count) > 1) {
+		newsig = kmem_cache_alloc(signal_cachep, GFP_KERNEL);
+		if (!newsig) {
+			kmem_cache_free(sighand_cachep, newsighand);
 			return -ENOMEM;
+		}
+		atomic_set(&newsig->count, 1);
+		newsig->group_exit = 0;
+		newsig->group_exit_code = 0;
+		newsig->group_exit_task = NULL;
+		newsig->group_stop_count = 0;
+		init_sigpending(&newsig->shared_pending);
+	}
 
 	if (thread_group_empty(current))
-		goto out;
+		goto no_thread_group;
 	/*
 	 * Kill all other threads in the thread group:
 	 */
-	spin_lock_irq(&oldsig->siglock);
+	spin_lock_irq(lock);
 	if (oldsig->group_exit) {
 		/*
 		 * Another group action in progress, just
 		 * return so that the signal is processed.
 		 */
-		spin_unlock_irq(&oldsig->siglock);
-		kmem_cache_free(sigact_cachep, newsig);
+		spin_unlock_irq(lock);
+		kmem_cache_free(sighand_cachep, newsighand);
+		if (newsig)
+			kmem_cache_free(signal_cachep, newsig);
 		return -EAGAIN;
 	}
 	oldsig->group_exit = 1;
@@ -598,13 +628,13 @@ static inline int de_thread(struct signal_struct *oldsig)
 	while (atomic_read(&oldsig->count) > count) {
 		oldsig->group_exit_task = current;
 		current->state = TASK_UNINTERRUPTIBLE;
-		spin_unlock_irq(&oldsig->siglock);
+		spin_unlock_irq(lock);
 		schedule();
-		spin_lock_irq(&oldsig->siglock);
+		spin_lock_irq(lock);
 		if (oldsig->group_exit_task)
 			BUG();
 	}
-	spin_unlock_irq(&oldsig->siglock);
+	spin_unlock_irq(lock);
 
 	/*
 	 * At this point all other threads have exited, all we have to
@@ -675,32 +705,29 @@ static inline int de_thread(struct signal_struct *oldsig)
 		release_task(leader);
         }
 
-out:
-	spin_lock_init(&newsig->siglock);
-	atomic_set(&newsig->count, 1);
-	newsig->group_exit = 0;
-	newsig->group_exit_code = 0;
-	newsig->group_exit_task = NULL;
-	newsig->group_stop_count = 0;
-	memcpy(newsig->action, current->sig->action, sizeof(newsig->action));
-	init_sigpending(&newsig->shared_pending);
+no_thread_group:
 
 	write_lock_irq(&tasklist_lock);
-	spin_lock(&oldsig->siglock);
-	spin_lock(&newsig->siglock);
+	spin_lock(&oldsighand->siglock);
+	spin_lock(&newsighand->siglock);
 
 	if (current == oldsig->curr_target)
 		oldsig->curr_target = next_thread(current);
-	current->sig = newsig;
+	if (newsig)
+		current->signal = newsig;
+	current->sighand = newsighand;
 	init_sigpending(&current->pending);
 	recalc_sigpending();
 
-	spin_unlock(&newsig->siglock);
-	spin_unlock(&oldsig->siglock);
+	spin_unlock(&newsighand->siglock);
+	spin_unlock(&oldsighand->siglock);
 	write_unlock_irq(&tasklist_lock);
 
-	if (atomic_dec_and_test(&oldsig->count))
-		kmem_cache_free(sigact_cachep, oldsig);
+	if (newsig && atomic_dec_and_test(&oldsig->count))
+		kmem_cache_free(signal_cachep, oldsig);
+
+	if (atomic_dec_and_test(&oldsighand->count))
+		kmem_cache_free(sighand_cachep, oldsighand);
 
 	if (!thread_group_empty(current))
 		BUG();
@@ -746,21 +773,20 @@ int flush_old_exec(struct linux_binprm * bprm)
 {
 	char * name;
 	int i, ch, retval;
-	struct signal_struct * oldsig = current->sig;
 
 	/* 
 	 * Release all of the old mmap stuff
 	 */
 	retval = exec_mmap(bprm->mm);
 	if (retval)
-		goto mmap_failed;
+		goto out;
 	/*
 	 * Make sure we have a private signal table and that
 	 * we are unassociated from the previous thread group.
 	 */
-	retval = de_thread(oldsig);
+	retval = de_thread(current);
 	if (retval)
-		goto flush_failed;
+		goto out;
 
 	/* This is the point of no return */
 
@@ -794,14 +820,7 @@ int flush_old_exec(struct linux_binprm * bprm)
 
 	return 0;
 
-mmap_failed:
-flush_failed:
-	spin_lock_irq(&current->sig->siglock);
-	if (current->sig != oldsig) {
-		kmem_cache_free(sigact_cachep, current->sig);
-		current->sig = oldsig;
-	}
-	spin_unlock_irq(&current->sig->siglock);
+out:
 	return retval;
 }
 
@@ -885,7 +904,7 @@ void compute_creds(struct linux_binprm *bprm)
 		if (must_not_trace_exec(current)
 		    || atomic_read(&current->fs->count) > 1
 		    || atomic_read(&current->files->count) > 1
-		    || atomic_read(&current->sig->count) > 1) {
+		    || atomic_read(&current->sighand->count) > 1) {
 			if(!capable(CAP_SETUID)) {
 				bprm->e_uid = current->uid;
 				bprm->e_gid = current->gid;
@@ -1302,8 +1321,8 @@ int do_coredump(long signr, int exit_code, struct pt_regs * regs)
 	}
 	mm->dumpable = 0;
 	init_completion(&mm->core_done);
-	current->sig->group_exit = 1;
-	current->sig->group_exit_code = exit_code;
+	current->signal->group_exit = 1;
+	current->signal->group_exit_code = exit_code;
 	coredump_wait(mm);
 
 	if (current->rlim[RLIMIT_CORE].rlim_cur < binfmt->min_coredump)
@@ -1330,7 +1349,7 @@ int do_coredump(long signr, int exit_code, struct pt_regs * regs)
 
 	retval = binfmt->core_dump(signr, regs, file);
 
-	current->sig->group_exit_code |= 0x80;
+	current->signal->group_exit_code |= 0x80;
 close_fail:
 	filp_close(file, NULL);
 fail_unlock:

fs/jbd/journal.c

@@ -205,10 +205,10 @@ int kjournald(void *arg)
 
 	lock_kernel();
 	daemonize();
-	spin_lock_irq(&current->sig->siglock);
+	spin_lock_irq(&current->sighand->siglock);
 	sigfillset(&current->blocked);
 	recalc_sigpending();
-	spin_unlock_irq(&current->sig->siglock);
+	spin_unlock_irq(&current->sighand->siglock);
 
 	sprintf(current->comm, "kjournald");
 

fs/lockd/clntproc.c

@@ -139,7 +139,7 @@ nlmclnt_proc(struct inode *inode, int cmd, struct file_lock *fl)
 	}
 
 	/* Keep the old signal mask */
-	spin_lock_irqsave(&current->sig->siglock, flags);
+	spin_lock_irqsave(&current->sighand->siglock, flags);
 	oldset = current->blocked;
 
 	/* If we're cleaning up locks because the process is exiting,
@@ -149,7 +149,7 @@ nlmclnt_proc(struct inode *inode, int cmd, struct file_lock *fl)
 	    && (current->flags & PF_EXITING)) {
 		sigfillset(&current->blocked);	/* Mask all signals */
 		recalc_sigpending();
-		spin_unlock_irqrestore(&current->sig->siglock, flags);
+		spin_unlock_irqrestore(&current->sighand->siglock, flags);
 
 		call = nlmclnt_alloc_call();
 		if (!call) {
@@ -158,7 +158,7 @@ nlmclnt_proc(struct inode *inode, int cmd, struct file_lock *fl)
 		}
 		call->a_flags = RPC_TASK_ASYNC;
 	} else {
-		spin_unlock_irqrestore(&current->sig->siglock, flags);
+		spin_unlock_irqrestore(&current->sighand->siglock, flags);
 		memset(call, 0, sizeof(*call));
 		locks_init_lock(&call->a_args.lock.fl);
 		locks_init_lock(&call->a_res.lock.fl);
@@ -183,10 +183,10 @@ nlmclnt_proc(struct inode *inode, int cmd, struct file_lock *fl)
 		kfree(call);
 
  out_restore:
-	spin_lock_irqsave(&current->sig->siglock, flags);
+	spin_lock_irqsave(&current->sighand->siglock, flags);
 	current->blocked = oldset;
 	recalc_sigpending();
-	spin_unlock_irqrestore(&current->sig->siglock, flags);
+	spin_unlock_irqrestore(&current->sighand->siglock, flags);
 
 done:
 	dprintk("lockd: clnt proc returns %d\n", status);
@@ -588,11 +588,11 @@ nlmclnt_cancel(struct nlm_host *host, struct file_lock *fl)
 	int		status;
 
 	/* Block all signals while setting up call */
-	spin_lock_irqsave(&current->sig->siglock, flags);
+	spin_lock_irqsave(&current->sighand->siglock, flags);
 	oldset = current->blocked;
 	sigfillset(&current->blocked);
 	recalc_sigpending();
-	spin_unlock_irqrestore(&current->sig->siglock, flags);
+	spin_unlock_irqrestore(&current->sighand->siglock, flags);
 
 	req = nlmclnt_alloc_call();
 	if (!req)
@@ -607,10 +607,10 @@ nlmclnt_cancel(struct nlm_host *host, struct file_lock *fl)
 	if (status < 0)
 		kfree(req);
 
-	spin_lock_irqsave(&current->sig->siglock, flags);
+	spin_lock_irqsave(&current->sighand->siglock, flags);
 	current->blocked = oldset;
 	recalc_sigpending();
-	spin_unlock_irqrestore(&current->sig->siglock, flags);
+	spin_unlock_irqrestore(&current->sighand->siglock, flags);
 
 	return status;
 }

fs/lockd/svc.c

@@ -101,10 +101,10 @@ lockd(struct svc_rqst *rqstp)
 	sprintf(current->comm, "lockd");
 
 	/* Process request with signals blocked.  */
-	spin_lock_irq(&current->sig->siglock);
+	spin_lock_irq(&current->sighand->siglock);
 	siginitsetinv(&current->blocked, sigmask(SIGKILL));
 	recalc_sigpending();
-	spin_unlock_irq(&current->sig->siglock);
+	spin_unlock_irq(&current->sighand->siglock);
 
 	/* kick rpciod */
 	rpciod_up();
@@ -126,9 +126,9 @@ lockd(struct svc_rqst *rqstp)
 	{
 		long timeout = MAX_SCHEDULE_TIMEOUT;
 		if (signalled()) {
-			spin_lock_irq(&current->sig->siglock);
+			spin_lock_irq(&current->sighand->siglock);
 			flush_signals(current);
-			spin_unlock_irq(&current->sig->siglock);
+			spin_unlock_irq(&current->sighand->siglock);
 			if (nlmsvc_ops) {
 				nlmsvc_invalidate_all();
 				grace_period_expire = set_grace_period();
@@ -297,9 +297,9 @@ lockd_down(void)
 			"lockd_down: lockd failed to exit, clearing pid\n");
 		nlmsvc_pid = 0;
 	}
-	spin_lock_irq(&current->sig->siglock);
+	spin_lock_irq(&current->sighand->siglock);
 	recalc_sigpending();
-	spin_unlock_irq(&current->sig->siglock);
+	spin_unlock_irq(&current->sighand->siglock);
 out:
 	up(&nlmsvc_sema);
 }

fs/nfsd/nfssvc.c

@@ -189,10 +189,10 @@ nfsd(struct svc_rqst *rqstp)
 	 */
 	for (;;) {
 		/* Block all but the shutdown signals */
-		spin_lock_irq(&current->sig->siglock);
+		spin_lock_irq(&current->sighand->siglock);
 		siginitsetinv(&current->blocked, SHUTDOWN_SIGS);
 		recalc_sigpending();
-		spin_unlock_irq(&current->sig->siglock);
+		spin_unlock_irq(&current->sighand->siglock);
 
 		/*
 		 * Find a socket with data available and call its
@@ -210,10 +210,10 @@ nfsd(struct svc_rqst *rqstp)
 		exp_readlock();
 
 		/* Process request with signals blocked.  */
-		spin_lock_irq(&current->sig->siglock);
+		spin_lock_irq(&current->sighand->siglock);
 		siginitsetinv(&current->blocked, ALLOWED_SIGS);
 		recalc_sigpending();
-		spin_unlock_irq(&current->sig->siglock);
+		spin_unlock_irq(&current->sighand->siglock);
 
 		svc_process(serv, rqstp);
 

fs/proc/array.c

@@ -190,16 +190,16 @@ static void collect_sigign_sigcatch(struct task_struct *p, sigset_t *ign,
 	sigemptyset(catch);
 
 	read_lock(&tasklist_lock);
-	if (p->sig) {
-		spin_lock_irq(&p->sig->siglock);
-		k = p->sig->action;
+	if (p->sighand) {
+		spin_lock_irq(&p->sighand->siglock);
+		k = p->sighand->action;
 		for (i = 1; i <= _NSIG; ++i, ++k) {
 			if (k->sa.sa_handler == SIG_IGN)
 				sigaddset(ign, i);
 			else if (k->sa.sa_handler != SIG_DFL)
 				sigaddset(catch, i);
 		}
-		spin_unlock_irq(&p->sig->siglock);
+		spin_unlock_irq(&p->sighand->siglock);
 	}
 	read_unlock(&tasklist_lock);
 }

include/linux/init_task.h

@@ -44,10 +44,14 @@
 }
 
 #define INIT_SIGNALS(sig) {	\
+	.count		= ATOMIC_INIT(1), 		\
+	.shared_pending	= { NULL, &sig.shared_pending.head, {{0}}}, \
+}
+
+#define INIT_SIGHAND(sighand) {	\
 	.count		= ATOMIC_INIT(1), 		\
 	.action		= { {{0,}}, }, 			\
 	.siglock	= SPIN_LOCK_UNLOCKED, 		\
-	.shared_pending	= { NULL, &sig.shared_pending.head, {{0}}}, \
 }
 
 /*
@@ -90,7 +94,8 @@
 	.thread		= INIT_THREAD,					\
 	.fs		= &init_fs,					\
 	.files		= &init_files,					\
-	.sig		= &init_signals,				\
+	.signal		= &init_signals,				\
+	.sighand	= &init_sighand,				\
 	.pending	= { NULL, &tsk.pending.head, {{0}}},		\
 	.blocked	= {{0}},					\
 	.alloc_lock	= SPIN_LOCK_UNLOCKED,				\

include/linux/sched.h

@@ -220,10 +220,21 @@ struct mm_struct {
 
 extern int mmlist_nr;
 
-struct signal_struct {
+struct sighand_struct {
 	atomic_t		count;
 	struct k_sigaction	action[_NSIG];
 	spinlock_t		siglock;
+};
+
+/*
+ * NOTE! "signal_struct" does not have it's own
+ * locking, because a shared signal_struct always
+ * implies a shared sighand_struct, so locking
+ * sighand_struct is always a proper superset of
+ * the locking of signal_struct.
+ */
+struct signal_struct {
+	atomic_t		count;
 
 	/* current thread group signal load-balancing target: */
 	task_t			*curr_target;
@@ -378,7 +389,8 @@ struct task_struct {
 /* namespace */
 	struct namespace *namespace;
 /* signal handlers */
-	struct signal_struct *sig;
+	struct signal_struct *signal;
+	struct sighand_struct *sighand;
 
 	sigset_t blocked, real_blocked;
 	struct sigpending pending;
@@ -589,6 +601,8 @@ extern void exit_thread(void);
 
 extern void exit_mm(struct task_struct *);
 extern void exit_files(struct task_struct *);
+extern void exit_signal(struct task_struct *);
+extern void __exit_signal(struct task_struct *);
 extern void exit_sighand(struct task_struct *);
 extern void __exit_sighand(struct task_struct *);
 

include/linux/slab.h

@@ -71,7 +71,8 @@ extern kmem_cache_t	*files_cachep;
 extern kmem_cache_t	*filp_cachep;
 extern kmem_cache_t	*dquot_cachep;
 extern kmem_cache_t	*fs_cachep;
-extern kmem_cache_t	*sigact_cachep;
+extern kmem_cache_t	*signal_cachep;
+extern kmem_cache_t	*sighand_cachep;
 extern kmem_cache_t	*bio_cachep;
 
 #endif	/* __KERNEL__ */

kernel/exit.c

@@ -76,6 +76,7 @@ void release_task(struct task_struct * p)
 	if (unlikely(p->ptrace))
 		__ptrace_unlink(p);
 	BUG_ON(!list_empty(&p->ptrace_list) || !list_empty(&p->ptrace_children));
+	__exit_signal(p);
 	__exit_sighand(p);
 	proc_dentry = __unhash_process(p);
 
@@ -546,7 +547,7 @@ static void exit_notify(struct task_struct *tsk)
 {
 	struct task_struct *t;
 
-	if (signal_pending(tsk) && !tsk->sig->group_exit
+	if (signal_pending(tsk) && !tsk->signal->group_exit
 	    && !thread_group_empty(tsk)) {
 		/*
 		 * This occurs when there was a race between our exit
@@ -558,14 +559,14 @@ static void exit_notify(struct task_struct *tsk)
 		 * sure someone gets all the pending signals.
 		 */
 		read_lock(&tasklist_lock);
-		spin_lock_irq(&tsk->sig->siglock);
+		spin_lock_irq(&tsk->sighand->siglock);
 		for (t = next_thread(tsk); t != tsk; t = next_thread(t))
 			if (!signal_pending(t) && !(t->flags & PF_EXITING)) {
 				recalc_sigpending_tsk(t);
 				if (signal_pending(t))
 					signal_wake_up(t, 0);
 			}
-		spin_unlock_irq(&tsk->sig->siglock);
+		spin_unlock_irq(&tsk->sighand->siglock);
 		read_unlock(&tasklist_lock);
 	}
 
@@ -708,9 +709,9 @@ task_t *next_thread(task_t *p)
 	struct list_head *tmp, *head = &link->pidptr->task_list;
 
 #if CONFIG_SMP
-	if (!p->sig)
+	if (!p->sighand)
 		BUG();
-	if (!spin_is_locked(&p->sig->siglock) &&
+	if (!spin_is_locked(&p->sighand->siglock) &&
 				!rwlock_is_locked(&tasklist_lock))
 		BUG();
 #endif
@@ -730,12 +731,13 @@ do_group_exit(int exit_code)
 {
 	BUG_ON(exit_code & 0x80); /* core dumps don't get here */
 
-	if (current->sig->group_exit)
-		exit_code = current->sig->group_exit_code;
+	if (current->signal->group_exit)
+		exit_code = current->signal->group_exit_code;
 	else if (!thread_group_empty(current)) {
-		struct signal_struct *const sig = current->sig;
+		struct signal_struct *const sig = current->signal;
+		struct sighand_struct *const sighand = current->sighand;
 		read_lock(&tasklist_lock);
-		spin_lock_irq(&sig->siglock);
+		spin_lock_irq(&sighand->siglock);
 		if (sig->group_exit)
 			/* Another thread got here before we took the lock.  */
 			exit_code = sig->group_exit_code;
@@ -744,7 +746,7 @@ do_group_exit(int exit_code)
 			sig->group_exit_code = exit_code;
 			zap_other_threads(current);
 		}
-		spin_unlock_irq(&sig->siglock);
+		spin_unlock_irq(&sighand->siglock);
 		read_unlock(&tasklist_lock);
 	}
 
@@ -838,8 +840,8 @@ static int wait_task_zombie(task_t *p, unsigned int *stat_addr, struct rusage *r
 
 	retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
 	if (!retval && stat_addr) {
-		if (p->sig->group_exit)
-			retval = put_user(p->sig->group_exit_code, stat_addr);
+		if (p->signal->group_exit)
+			retval = put_user(p->signal->group_exit_code, stat_addr);
 		else
 			retval = put_user(p->exit_code, stat_addr);
 	}
@@ -879,7 +881,7 @@ static int wait_task_stopped(task_t *p, int delayed_group_leader,
 	if (!p->exit_code)
 		return 0;
 	if (delayed_group_leader && !(p->ptrace & PT_PTRACED) &&
-	    p->sig && p->sig->group_stop_count > 0)
+	    p->signal && p->signal->group_stop_count > 0)
 		/*
 		 * A group stop is in progress and this is the group leader.
 		 * We won't report until all threads have stopped.
@@ -1004,7 +1006,7 @@ asmlinkage long sys_wait4(pid_t pid,unsigned int * stat_addr, int options, struc
 		if (options & __WNOTHREAD)
 			break;
 		tsk = next_thread(tsk);
-		if (tsk->sig != current->sig)
+		if (tsk->signal != current->signal)
 			BUG();
 	} while (tsk != current);
 	read_unlock(&tasklist_lock);

kernel/fork.c

@@ -665,23 +665,39 @@ static int copy_files(unsigned long clone_flags, struct task_struct * tsk)
 
 static inline int copy_sighand(unsigned long clone_flags, struct task_struct * tsk)
 {
-	struct signal_struct *sig;
+	struct sighand_struct *sig;
 
-	if (clone_flags & CLONE_SIGHAND) {
-		atomic_inc(&current->sig->count);
+	if (clone_flags & (CLONE_SIGHAND | CLONE_THREAD)) {
+		atomic_inc(&current->sighand->count);
 		return 0;
 	}
-	sig = kmem_cache_alloc(sigact_cachep, GFP_KERNEL);
-	tsk->sig = sig;
+	sig = kmem_cache_alloc(sighand_cachep, GFP_KERNEL);
+	tsk->sighand = sig;
 	if (!sig)
 		return -1;
 	spin_lock_init(&sig->siglock);
 	atomic_set(&sig->count, 1);
+	memcpy(sig->action, current->sighand->action, sizeof(sig->action));
+	return 0;
+}
+
+static inline int copy_signal(unsigned long clone_flags, struct task_struct * tsk)
+{
+	struct signal_struct *sig;
+
+	if (clone_flags & CLONE_THREAD) {
+		atomic_inc(&current->signal->count);
+		return 0;
+	}
+	sig = kmem_cache_alloc(signal_cachep, GFP_KERNEL);
+	tsk->signal = sig;
+	if (!sig)
+		return -1;
+	atomic_set(&sig->count, 1);
 	sig->group_exit = 0;
 	sig->group_exit_code = 0;
 	sig->group_exit_task = NULL;
 	sig->group_stop_count = 0;
-	memcpy(sig->action, current->sig->action, sizeof(sig->action));
 	sig->curr_target = NULL;
 	init_sigpending(&sig->shared_pending);
 
@@ -831,8 +847,10 @@ static struct task_struct *copy_process(unsigned long clone_flags,
 		goto bad_fork_cleanup_files;
 	if (copy_sighand(clone_flags, p))
 		goto bad_fork_cleanup_fs;
-	if (copy_mm(clone_flags, p))
+	if (copy_signal(clone_flags, p))
 		goto bad_fork_cleanup_sighand;
+	if (copy_mm(clone_flags, p))
+		goto bad_fork_cleanup_signal;
 	if (copy_namespace(clone_flags, p))
 		goto bad_fork_cleanup_mm;
 	retval = copy_thread(0, clone_flags, stack_start, stack_size, p, regs);
@@ -923,31 +941,31 @@ static struct task_struct *copy_process(unsigned long clone_flags,
 	p->parent = p->real_parent;
 
 	if (clone_flags & CLONE_THREAD) {
-		spin_lock(&current->sig->siglock);
+		spin_lock(&current->sighand->siglock);
 		/*
 		 * Important: if an exit-all has been started then
 		 * do not create this new thread - the whole thread
 		 * group is supposed to exit anyway.
 		 */
-		if (current->sig->group_exit) {
-			spin_unlock(&current->sig->siglock);
+		if (current->signal->group_exit) {
+			spin_unlock(&current->sighand->siglock);
 			write_unlock_irq(&tasklist_lock);
 			goto bad_fork_cleanup_namespace;
 		}
 		p->tgid = current->tgid;
 		p->group_leader = current->group_leader;
 
-		if (current->sig->group_stop_count > 0) {
+		if (current->signal->group_stop_count > 0) {
 			/*
 			 * There is an all-stop in progress for the group.
 			 * We ourselves will stop as soon as we check signals.
 			 * Make the new thread part of that group stop too.
 			 */
-			current->sig->group_stop_count++;
+			current->signal->group_stop_count++;
 			set_tsk_thread_flag(p, TIF_SIGPENDING);
 		}
 
-		spin_unlock(&current->sig->siglock);
+		spin_unlock(&current->sighand->siglock);
 	}
 
 	SET_LINKS(p);
@@ -977,6 +995,8 @@ static struct task_struct *copy_process(unsigned long clone_flags,
 	exit_namespace(p);
 bad_fork_cleanup_mm:
 	exit_mm(p);
+bad_fork_cleanup_signal:
+	exit_signal(p);
 bad_fork_cleanup_sighand:
 	exit_sighand(p);
 bad_fork_cleanup_fs:
@@ -1077,8 +1097,11 @@ struct task_struct *do_fork(unsigned long clone_flags,
 	return p;
 }
 
-/* SLAB cache for signal_struct structures (tsk->sig) */
-kmem_cache_t *sigact_cachep;
+/* SLAB cache for signal_struct structures (tsk->signal) */
+kmem_cache_t *signal_cachep;
+
+/* SLAB cache for sighand_struct structures (tsk->sighand) */
+kmem_cache_t *sighand_cachep;
 
 /* SLAB cache for files_struct structures (tsk->files) */
 kmem_cache_t *files_cachep;
@@ -1094,11 +1117,17 @@ kmem_cache_t *mm_cachep;
 
 void __init proc_caches_init(void)
 {
-	sigact_cachep = kmem_cache_create("signal_act",
+	sighand_cachep = kmem_cache_create("sighand_cache",
+			sizeof(struct sighand_struct), 0,
+			SLAB_HWCACHE_ALIGN, NULL, NULL);
+	if (!sighand_cachep)
+		panic("Cannot create sighand SLAB cache");
+
+	signal_cachep = kmem_cache_create("signal_cache",
 			sizeof(struct signal_struct), 0,
 			SLAB_HWCACHE_ALIGN, NULL, NULL);
-	if (!sigact_cachep)
-		panic("Cannot create signal action SLAB cache");
+	if (!signal_cachep)
+		panic("Cannot create signal SLAB cache");
 
 	files_cachep = kmem_cache_create("files_cache", 
 			 sizeof(struct files_struct), 0, 

kernel/kmod.c

@@ -111,12 +111,12 @@ int exec_usermodehelper(char *program_path, char *argv[], char *envp[])
 	   as the super user right after the execve fails if you time
 	   the signal just right.
 	*/
-	spin_lock_irq(&curtask->sig->siglock);
+	spin_lock_irq(&curtask->sighand->siglock);
 	sigemptyset(&curtask->blocked);
 	flush_signals(curtask);
 	flush_signal_handlers(curtask);
 	recalc_sigpending();
-	spin_unlock_irq(&curtask->sig->siglock);
+	spin_unlock_irq(&curtask->sighand->siglock);
 
 	for (i = 0; i < curtask->files->max_fds; i++ ) {
 		if (curtask->files->fd[i]) close(i);
@@ -239,20 +239,20 @@ int request_module(const char * module_name)
 	}
 
 	/* Block everything but SIGKILL/SIGSTOP */
-	spin_lock_irq(&current->sig->siglock);
+	spin_lock_irq(&current->sighand->siglock);
 	tmpsig = current->blocked;
 	siginitsetinv(&current->blocked, sigmask(SIGKILL) | sigmask(SIGSTOP));
 	recalc_sigpending();
-	spin_unlock_irq(&current->sig->siglock);
+	spin_unlock_irq(&current->sighand->siglock);
 
 	waitpid_result = waitpid(pid, NULL, __WCLONE);
 	atomic_dec(&kmod_concurrent);
 
 	/* Allow signals again.. */
-	spin_lock_irq(&current->sig->siglock);
+	spin_lock_irq(&current->sighand->siglock);
 	current->blocked = tmpsig;
 	recalc_sigpending();
-	spin_unlock_irq(&current->sig->siglock);
+	spin_unlock_irq(&current->sighand->siglock);
 
 	if (waitpid_result != pid) {
 		printk(KERN_ERR "request_module[%s]: waitpid(%d,...) failed, errno %d\n",

kernel/workqueue.c

@@ -180,10 +180,10 @@ static int worker_thread(void *__startup)
 	set_user_nice(current, -10);
 	set_cpus_allowed(current, 1UL << cpu);
 
-	spin_lock_irq(&current->sig->siglock);
+	spin_lock_irq(&current->sighand->siglock);
 	siginitsetinv(&current->blocked, sigmask(SIGCHLD));
 	recalc_sigpending();
-	spin_unlock_irq(&current->sig->siglock);
+	spin_unlock_irq(&current->sighand->siglock);
 
 	complete(&startup->done);
 
@@ -213,10 +213,10 @@ static int worker_thread(void *__startup)
 				/* SIGCHLD - auto-reaping */ ;
 
 			/* zap all other signals */
-			spin_lock_irq(&current->sig->siglock);
+			spin_lock_irq(&current->sighand->siglock);
 			flush_signals(current);
 			recalc_sigpending();
-			spin_unlock_irq(&current->sig->siglock);
+			spin_unlock_irq(&current->sighand->siglock);
 		}
 	}
 	remove_wait_queue(&cwq->more_work, &wait);

mm/pdflush.c

@@ -90,10 +90,10 @@ static int __pdflush(struct pdflush_work *my_work)
 	strcpy(current->comm, "pdflush");
 
 	/* interruptible sleep, so block all signals */
-	spin_lock_irq(&current->sig->siglock);
+	spin_lock_irq(&current->sighand->siglock);
 	siginitsetinv(&current->blocked, 0);
 	recalc_sigpending();
-	spin_unlock_irq(&current->sig->siglock);
+	spin_unlock_irq(&current->sighand->siglock);
 
 	current->flags |= PF_FLUSHER;
 	my_work->fn = NULL;

net/sunrpc/clnt.c

@@ -233,27 +233,27 @@ void rpc_clnt_sigmask(struct rpc_clnt *clnt, sigset_t *oldset)
 	
 	/* Turn off various signals */
 	if (clnt->cl_intr) {
-		struct k_sigaction *action = current->sig->action;
+		struct k_sigaction *action = current->sighand->action;
 		if (action[SIGINT-1].sa.sa_handler == SIG_DFL)
 			sigallow |= sigmask(SIGINT);
 		if (action[SIGQUIT-1].sa.sa_handler == SIG_DFL)
 			sigallow |= sigmask(SIGQUIT);
 	}
-	spin_lock_irqsave(&current->sig->siglock, irqflags);
+	spin_lock_irqsave(&current->sighand->siglock, irqflags);
 	*oldset = current->blocked;
 	siginitsetinv(&current->blocked, sigallow & ~oldset->sig[0]);
 	recalc_sigpending();
-	spin_unlock_irqrestore(&current->sig->siglock, irqflags);
+	spin_unlock_irqrestore(&current->sighand->siglock, irqflags);
 }
 
 void rpc_clnt_sigunmask(struct rpc_clnt *clnt, sigset_t *oldset)
 {
 	unsigned long	irqflags;
 	
-	spin_lock_irqsave(&current->sig->siglock, irqflags);
+	spin_lock_irqsave(&current->sighand->siglock, irqflags);
 	current->blocked = *oldset;
 	recalc_sigpending();
-	spin_unlock_irqrestore(&current->sig->siglock, irqflags);
+	spin_unlock_irqrestore(&current->sighand->siglock, irqflags);
 }
 
 /*

net/sunrpc/sched.c

@@ -964,10 +964,10 @@ rpciod(void *ptr)
 
 	daemonize();
 
-	spin_lock_irq(&current->sig->siglock);
+	spin_lock_irq(&current->sighand->siglock);
 	siginitsetinv(&current->blocked, sigmask(SIGKILL));
 	recalc_sigpending();
-	spin_unlock_irq(&current->sig->siglock);
+	spin_unlock_irq(&current->sighand->siglock);
 
 	strcpy(current->comm, "rpciod");
 
@@ -1022,9 +1022,9 @@ rpciod_killall(void)
 		}
 	}
 
-	spin_lock_irqsave(&current->sig->siglock, flags);
+	spin_lock_irqsave(&current->sighand->siglock, flags);
 	recalc_sigpending();
-	spin_unlock_irqrestore(&current->sig->siglock, flags);
+	spin_unlock_irqrestore(&current->sighand->siglock, flags);
 }
 
 /*
@@ -1100,9 +1100,9 @@ rpciod_down(void)
 		}
 		interruptible_sleep_on(&rpciod_killer);
 	}
-	spin_lock_irqsave(&current->sig->siglock, flags);
+	spin_lock_irqsave(&current->sighand->siglock, flags);
 	recalc_sigpending();
-	spin_unlock_irqrestore(&current->sig->siglock, flags);
+	spin_unlock_irqrestore(&current->sighand->siglock, flags);
 out:
 	up(&rpciod_sema);
 	MOD_DEC_USE_COUNT;

net/sunrpc/svc.c

@@ -235,9 +235,9 @@ svc_register(struct svc_serv *serv, int proto, unsigned short port)
 	}
 
 	if (!port) {
-		spin_lock_irqsave(&current->sig->siglock, flags);
+		spin_lock_irqsave(&current->sighand->siglock, flags);
 		recalc_sigpending();
-		spin_unlock_irqrestore(&current->sig->siglock, flags);
+		spin_unlock_irqrestore(&current->sighand->siglock, flags);
 	}
 
 	return error;

security/capability.c

@@ -133,7 +133,7 @@ void cap_bprm_compute_creds (struct linux_binprm *bprm)
 		if (must_not_trace_exec (current)
 		    || atomic_read (&current->fs->count) > 1
 		    || atomic_read (&current->files->count) > 1
-		    || atomic_read (&current->sig->count) > 1) {
+		    || atomic_read (&current->sighand->count) > 1) {
 			if (!capable (CAP_SETPCAP)) {
 				new_permitted = cap_intersect (new_permitted,
 							       current->