[PATCH v3 00/17] signal: refactor some functions

[PATCH v3 00/17] signal: refactor some functions

[Christian Brauner]

Hey,

This series refactors a bunch of functions in signal.c to simplify parts
of the code.
As requested, v3 drops all 3 commits that were pure coding-style
changes.
The greatest single change is declaring the static do_sigpending()
helper as void which makes it possible to remove a bunch of unnecessary
checks in the syscalls later on.

Thanks!
Christian

Christian Brauner (17):
  signal: make force_sigsegv() void
  signal: make kill_as_cred_perm() return bool
  signal: make may_ptrace_stop() return bool
  signal: make do_sigpending() void
  signal: simplify rt_sigaction()
  signal: make kill_ok_by_cred() return bool
  signal: make sig_handler_ignored() return bool
  signal: make sig_task_ignored() return bool
  signal: make sig_ignored() return bool
  signal: make has_pending_signals() return bool
  signal: make recalc_sigpending_tsk() return bool
  signal: make unhandled_signal() return bool
  signal: make flush_sigqueue_mask() void
  signal: make wants_signal() return bool
  signal: make legacy_queue() return bool
  signal: make sigkill_pending() return bool
  signal: make get_signal() return bool

 include/linux/sched/signal.h |   2 +-
 include/linux/signal.h       |   4 +-
 kernel/signal.c              | 170 +++++++++++++++++------------------
 3 files changed, 86 insertions(+), 90 deletions(-)

-- 
2.17.0

[PATCH v3 01/17] signal: make force_sigsegv() void

[Christian Brauner]

force_sigsegv() returned 0 unconditionally so it doesn't make sense to have
it return at all. In addition, there are no callers that check
force_sigsegv()'s return value.

Signed-off-by: Christian Brauner <christian@brauner.io>
---
v2->v3:
* unchanged
v1->v2:
* unchanged
v0->v1:
* unchanged
---
 include/linux/sched/signal.h | 2 +-
 kernel/signal.c              | 7 ++-----
 2 files changed, 3 insertions(+), 6 deletions(-)

diff --git a/include/linux/sched/signal.h b/include/linux/sched/signal.h
index 113d1ad1ced7..e138ac16c650 100644
--- a/include/linux/sched/signal.h
+++ b/include/linux/sched/signal.h
@@ -314,7 +314,7 @@ int force_sig_pkuerr(void __user *addr, u32 pkey);
 int force_sig_ptrace_errno_trap(int errno, void __user *addr);
 
 extern int send_sig_info(int, struct siginfo *, struct task_struct *);
-extern int force_sigsegv(int, struct task_struct *);
+extern void force_sigsegv(int sig, struct task_struct *p);
 extern int force_sig_info(int, struct siginfo *, struct task_struct *);
 extern int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp);
 extern int kill_pid_info(int sig, struct siginfo *info, struct pid *pid);
diff --git a/kernel/signal.c b/kernel/signal.c
index 9c33163a6165..c756008d589e 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1468,8 +1468,7 @@ send_sig(int sig, struct task_struct *p, int priv)
 	return send_sig_info(sig, __si_special(priv), p);
 }
 
-void
-force_sig(int sig, struct task_struct *p)
+void force_sig(int sig, struct task_struct *p)
 {
 	force_sig_info(sig, SEND_SIG_PRIV, p);
 }
@@ -1480,8 +1479,7 @@ force_sig(int sig, struct task_struct *p)
  * the problem was already a SIGSEGV, we'll want to
  * make sure we don't even try to deliver the signal..
  */
-int
-force_sigsegv(int sig, struct task_struct *p)
+void force_sigsegv(int sig, struct task_struct *p)
 {
 	if (sig == SIGSEGV) {
 		unsigned long flags;
@@ -1490,7 +1488,6 @@ force_sigsegv(int sig, struct task_struct *p)
 		spin_unlock_irqrestore(&p->sighand->siglock, flags);
 	}
 	force_sig(SIGSEGV, p);
-	return 0;
 }
 
 int force_sig_fault(int sig, int code, void __user *addr
-- 
2.17.0

[PATCH v3 02/17] signal: make kill_as_cred_perm() return bool

[Christian Brauner]

kill_as_cred_perm() already behaves like a boolean function. Let's actually
declare it as such too.

Signed-off-by: Christian Brauner <christian@brauner.io>
---
v2->v3:
* unchanged
v1->v2:
* unchanged
v0->v1:
* simplify to use a single return
---
 kernel/signal.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/kernel/signal.c b/kernel/signal.c
index c756008d589e..6c71d6b8d2b8 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1349,14 +1349,15 @@ static int kill_proc_info(int sig, struct siginfo *info, pid_t pid)
 	return error;
 }
 
-static int kill_as_cred_perm(const struct cred *cred,
-			     struct task_struct *target)
+static inline bool kill_as_cred_perm(const struct cred *cred,
+				     struct task_struct *target)
 {
 	const struct cred *pcred = __task_cred(target);
-	if (!uid_eq(cred->euid, pcred->suid) && !uid_eq(cred->euid, pcred->uid) &&
-	    !uid_eq(cred->uid,  pcred->suid) && !uid_eq(cred->uid,  pcred->uid))
-		return 0;
-	return 1;
+
+	return uid_eq(cred->euid, pcred->suid) ||
+	       uid_eq(cred->euid, pcred->uid) ||
+	       uid_eq(cred->uid, pcred->suid) ||
+	       uid_eq(cred->uid, pcred->uid);
 }
 
 /* like kill_pid_info(), but doesn't use uid/euid of "current" */
-- 
2.17.0

[PATCH v3 03/17] signal: make may_ptrace_stop() return bool

[Christian Brauner]

may_ptrace_stop() already behaves like a boolean function. Let's actually
declare it as such too.

Signed-off-by: Christian Brauner <christian@brauner.io>
---
v2->v3:
* [Oleg Nestorov] s/likely/unlikely logic
v1->v2:
* unchanged
v0->v1:
* unchanged
---
 kernel/signal.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/signal.c b/kernel/signal.c
index 6c71d6b8d2b8..1848959a3b72 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1889,10 +1889,10 @@ static void do_notify_parent_cldstop(struct task_struct *tsk,
 	spin_unlock_irqrestore(&sighand->siglock, flags);
 }
 
-static inline int may_ptrace_stop(void)
+static inline bool may_ptrace_stop(void)
 {
 	if (!likely(current->ptrace))
-		return 0;
+		return false;
 	/*
 	 * Are we in the middle of do_coredump?
 	 * If so and our tracer is also part of the coredump stopping
@@ -1908,9 +1908,9 @@ static inline int may_ptrace_stop(void)
 	 */
 	if (unlikely(current->mm->core_state) &&
 	    unlikely(current->mm == current->parent->mm))
-		return 0;
+		return false;
 
-	return 1;
+	return true;
 }
 
 /*
-- 
2.17.0

[PATCH v3 04/17] signal: make do_sigpending() void

[Christian Brauner]

do_sigpending() returned 0 unconditionally so it doesn't make sense to have
it return at all. This allows us to simplify a bunch of syscall callers.

Signed-off-by: Christian Brauner <christian@brauner.io>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Oleg Nesterov <oleg@redhat.com>
---
v2->v3:
* added Oleg's Acked-by
v1->v2:
* unchanged
v0->v1:
* unchanged
---
 kernel/signal.c | 41 ++++++++++++++++++++---------------------
 1 file changed, 20 insertions(+), 21 deletions(-)

diff --git a/kernel/signal.c b/kernel/signal.c
index 1848959a3b72..e17ae40ee6bd 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2767,7 +2767,7 @@ COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset,
 }
 #endif
 
-static int do_sigpending(sigset_t *set)
+static void do_sigpending(sigset_t *set)
 {
 	spin_lock_irq(&current->sighand->siglock);
 	sigorsets(set, &current->pending.signal,
@@ -2776,7 +2776,6 @@ static int do_sigpending(sigset_t *set)
 
 	/* Outside the lock because only this thread touches it.  */
 	sigandsets(set, &current->blocked, set);
-	return 0;
 }
 
 /**
@@ -2788,15 +2787,16 @@ static int do_sigpending(sigset_t *set)
 SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, uset, size_t, sigsetsize)
 {
 	sigset_t set;
-	int err;
 
 	if (sigsetsize > sizeof(*uset))
 		return -EINVAL;
 
-	err = do_sigpending(&set);
-	if (!err && copy_to_user(uset, &set, sigsetsize))
-		err = -EFAULT;
-	return err;
+	do_sigpending(&set);
+
+	if (copy_to_user(uset, &set, sigsetsize))
+		return -EFAULT;
+
+	return 0;
 }
 
 #ifdef CONFIG_COMPAT
@@ -2804,15 +2804,13 @@ COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset,
 		compat_size_t, sigsetsize)
 {
 	sigset_t set;
-	int err;
 
 	if (sigsetsize > sizeof(*uset))
 		return -EINVAL;
 
-	err = do_sigpending(&set);
-	if (!err)
-		err = put_compat_sigset(uset, &set, sigsetsize);
-	return err;
+	do_sigpending(&set);
+
+	return put_compat_sigset(uset, &set, sigsetsize);
 }
 #endif
 
@@ -3647,25 +3645,26 @@ int __compat_save_altstack(compat_stack_t __user *uss, unsigned long sp)
 SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, uset)
 {
 	sigset_t set;
-	int err;
 
 	if (sizeof(old_sigset_t) > sizeof(*uset))
 		return -EINVAL;
 
-	err = do_sigpending(&set);
-	if (!err && copy_to_user(uset, &set, sizeof(old_sigset_t)))
-		err = -EFAULT;
-	return err;
+	do_sigpending(&set);
+
+	if (copy_to_user(uset, &set, sizeof(old_sigset_t)))
+		return -EFAULT;
+
+	return 0;
 }
 
 #ifdef CONFIG_COMPAT
 COMPAT_SYSCALL_DEFINE1(sigpending, compat_old_sigset_t __user *, set32)
 {
 	sigset_t set;
-	int err = do_sigpending(&set);
-	if (!err)
-		err = put_user(set.sig[0], set32);
-	return err;
+
+	do_sigpending(&set);
+
+	return put_user(set.sig[0], set32);
 }
 #endif
 
-- 
2.17.0

[PATCH v3 05/17] signal: simplify rt_sigaction()

[Christian Brauner]

The goto is not needed and does not add any clarity. Simply return -EINVAL
on unexpected sigset_t struct size directly.

Signed-off-by: Christian Brauner <christian@brauner.io>
Acked-by: Oleg Nesterov <oleg@redhat.com>
---
v2->v3:
* added Oleg's Acked-by
v1->v2:
* [Christoph Hellwig] additional cleanups
v0->v1:
* unchanged
---
 kernel/signal.c | 22 ++++++++++------------
 1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/kernel/signal.c b/kernel/signal.c
index e17ae40ee6bd..21508900805b 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -3735,25 +3735,23 @@ SYSCALL_DEFINE4(rt_sigaction, int, sig,
 		size_t, sigsetsize)
 {
 	struct k_sigaction new_sa, old_sa;
-	int ret = -EINVAL;
+	int ret;
 
 	/* XXX: Don't preclude handling different sized sigset_t's.  */
 	if (sigsetsize != sizeof(sigset_t))
-		goto out;
+		return -EINVAL;
 
-	if (act) {
-		if (copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa)))
-			return -EFAULT;
-	}
+	if (act && copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa)))
+		return -EFAULT;
 
 	ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL);
+	if (ret)
+		return ret;
 
-	if (!ret && oact) {
-		if (copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa)))
-			return -EFAULT;
-	}
-out:
-	return ret;
+	if (oact && copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa)))
+		return -EFAULT;
+
+	return 0;
 }
 #ifdef CONFIG_COMPAT
 COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig,
-- 
2.17.0

[PATCH v3 06/17] signal: make kill_ok_by_cred() return bool

[Christian Brauner]

kill_ok_by_cred() already behaves like a boolean function. Let's actually
declare it as such too.

Signed-off-by: Christian Brauner <christian@brauner.io>
---
v2->v3:
* unchanged
v1->v2:
* unchanged
v0->v1:
* unchanged
---
 kernel/signal.c | 17 ++++++-----------
 1 file changed, 6 insertions(+), 11 deletions(-)

diff --git a/kernel/signal.c b/kernel/signal.c
index 21508900805b..dd239a8d7d2c 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -717,21 +717,16 @@ static inline bool si_fromuser(const struct siginfo *info)
 /*
  * called with RCU read lock from check_kill_permission()
  */
-static int kill_ok_by_cred(struct task_struct *t)
+static bool kill_ok_by_cred(struct task_struct *t)
 {
 	const struct cred *cred = current_cred();
 	const struct cred *tcred = __task_cred(t);
 
-	if (uid_eq(cred->euid, tcred->suid) ||
-	    uid_eq(cred->euid, tcred->uid)  ||
-	    uid_eq(cred->uid,  tcred->suid) ||
-	    uid_eq(cred->uid,  tcred->uid))
-		return 1;
-
-	if (ns_capable(tcred->user_ns, CAP_KILL))
-		return 1;
-
-	return 0;
+	return uid_eq(cred->euid, tcred->suid) ||
+	       uid_eq(cred->euid, tcred->uid) ||
+	       uid_eq(cred->uid, tcred->suid) ||
+	       uid_eq(cred->uid, tcred->uid) ||
+	       ns_capable(tcred->user_ns, CAP_KILL);
 }
 
 /*
-- 
2.17.0

[PATCH v3 07/17] signal: make sig_handler_ignored() return bool

[Christian Brauner]

sig_handler_ignored() already behaves like a boolean function. Let's
actually declare it as such too.

Signed-off-by: Christian Brauner <christian@brauner.io>
---
v2->v3:
* unchanged
v1->v2:
* unchanged
v0->v1:
* patch added
---
 kernel/signal.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/signal.c b/kernel/signal.c
index dd239a8d7d2c..13061f388042 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -65,11 +65,11 @@ static void __user *sig_handler(struct task_struct *t, int sig)
 	return t->sighand->action[sig - 1].sa.sa_handler;
 }
 
-static int sig_handler_ignored(void __user *handler, int sig)
+static inline bool sig_handler_ignored(void __user *handler, int sig)
 {
 	/* Is it explicitly or implicitly ignored? */
 	return handler == SIG_IGN ||
-		(handler == SIG_DFL && sig_kernel_ignore(sig));
+	       (handler == SIG_DFL && sig_kernel_ignore(sig));
 }
 
 static int sig_task_ignored(struct task_struct *t, int sig, bool force)
-- 
2.17.0

[PATCH v3 08/17] signal: make sig_task_ignored() return bool

[Christian Brauner]

sig_task_ignored() already behaves like a boolean function. Let's actually
declare it as such too.

Signed-off-by: Christian Brauner <christian@brauner.io>
---
v2->v3:
* unchanged
v1->v2:
* unchanged
v0->v1:
* patch added
---
 kernel/signal.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/signal.c b/kernel/signal.c
index 13061f388042..ff2ea82e376b 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -72,7 +72,7 @@ static inline bool sig_handler_ignored(void __user *handler, int sig)
 	       (handler == SIG_DFL && sig_kernel_ignore(sig));
 }
 
-static int sig_task_ignored(struct task_struct *t, int sig, bool force)
+static bool sig_task_ignored(struct task_struct *t, int sig, bool force)
 {
 	void __user *handler;
 
@@ -80,7 +80,7 @@ static int sig_task_ignored(struct task_struct *t, int sig, bool force)
 
 	if (unlikely(t->signal->flags & SIGNAL_UNKILLABLE) &&
 	    handler == SIG_DFL && !(force && sig_kernel_only(sig)))
-		return 1;
+		return true;
 
 	return sig_handler_ignored(handler, sig);
 }
-- 
2.17.0

[PATCH v3 09/17] signal: make sig_ignored() return bool

[Christian Brauner]

sig_ignored() already behaves like a boolean function. Let's actually
declare it as such too.

Signed-off-by: Christian Brauner <christian@brauner.io>
---
v2->v3:
* unchanged
v1->v2:
* unchanged
v0->v1:
* patch added
---
 kernel/signal.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/signal.c b/kernel/signal.c
index ff2ea82e376b..fed938c2e273 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -85,7 +85,7 @@ static bool sig_task_ignored(struct task_struct *t, int sig, bool force)
 	return sig_handler_ignored(handler, sig);
 }
 
-static int sig_ignored(struct task_struct *t, int sig, bool force)
+static bool sig_ignored(struct task_struct *t, int sig, bool force)
 {
 	/*
 	 * Blocked signals are never ignored, since the
@@ -93,7 +93,7 @@ static int sig_ignored(struct task_struct *t, int sig, bool force)
 	 * unblocked.
 	 */
 	if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig))
-		return 0;
+		return false;
 
 	/*
 	 * Tracers may want to know about even ignored signal unless it
@@ -101,7 +101,7 @@ static int sig_ignored(struct task_struct *t, int sig, bool force)
 	 * by SIGNAL_UNKILLABLE task.
 	 */
 	if (t->ptrace && sig != SIGKILL)
-		return 0;
+		return false;
 
 	return sig_task_ignored(t, sig, force);
 }
-- 
2.17.0

[PATCH v3 10/17] signal: make has_pending_signals() return bool

[Christian Brauner]

has_pending_signals() already behaves like a boolean function. Let's
actually declare it as such too.

Signed-off-by: Christian Brauner <christian@brauner.io>
---
v2->v3:
* [Oleg Nestorov] remove other non-functional changes
v1->v2:
* unchanged
v0->v1:
* patch added
---
 kernel/signal.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/signal.c b/kernel/signal.c
index fed938c2e273..c2af9a7f73b3 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -110,7 +110,7 @@ static bool sig_ignored(struct task_struct *t, int sig, bool force)
  * Re-calculate pending state from the set of locally pending
  * signals, globally pending signals, and blocked signals.
  */
-static inline int has_pending_signals(sigset_t *signal, sigset_t *blocked)
+static inline bool has_pending_signals(sigset_t *signal, sigset_t *blocked)
 {
 	unsigned long ready;
 	long i;
-- 
2.17.0

[PATCH v3 11/17] signal: make recalc_sigpending_tsk() return bool

[Christian Brauner]

recalc_sigpending_tsk() already behaves like a boolean function. Let's
actually declare it as such too.

Signed-off-by: Christian Brauner <christian@brauner.io>
---
v2->v3:
* unchanged
v1->v2:
* unchanged
v0->v1:
* patch added
---
 kernel/signal.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/kernel/signal.c b/kernel/signal.c
index c2af9a7f73b3..41f9b91db209 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -138,20 +138,21 @@ static inline bool has_pending_signals(sigset_t *signal, sigset_t *blocked)
 
 #define PENDING(p,b) has_pending_signals(&(p)->signal, (b))
 
-static int recalc_sigpending_tsk(struct task_struct *t)
+static bool recalc_sigpending_tsk(struct task_struct *t)
 {
 	if ((t->jobctl & JOBCTL_PENDING_MASK) ||
 	    PENDING(&t->pending, &t->blocked) ||
 	    PENDING(&t->signal->shared_pending, &t->blocked)) {
 		set_tsk_thread_flag(t, TIF_SIGPENDING);
-		return 1;
+		return true;
 	}
+
 	/*
 	 * We must never clear the flag in another thread, or in current
 	 * when it's possible the current syscall is returning -ERESTART*.
 	 * So we don't clear it here, and only callers who know they should do.
 	 */
-	return 0;
+	return false;
 }
 
 /*
-- 
2.17.0

[PATCH v3 12/17] signal: make unhandled_signal() return bool

[Christian Brauner]

unhandled_signal() already behaves like a boolean function. Let's actually
declare it as such too.
All callers treat it as such too.

Signed-off-by: Christian Brauner <christian@brauner.io>
---
v2->v3:
* unchanged
v1->v2:
* unchanged
v0->v1:
* patch added
---
 include/linux/signal.h | 2 +-
 kernel/signal.c        | 8 +++++---
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/include/linux/signal.h b/include/linux/signal.h
index a9bc7e1b077e..1145d7061ed9 100644
--- a/include/linux/signal.h
+++ b/include/linux/signal.h
@@ -284,7 +284,7 @@ static inline void disallow_signal(int sig)
 
 extern struct kmem_cache *sighand_cachep;
 
-int unhandled_signal(struct task_struct *tsk, int sig);
+extern bool unhandled_signal(struct task_struct *tsk, int sig);
 
 /*
  * In POSIX a signal is sent either to a specific thread (Linux task)
diff --git a/kernel/signal.c b/kernel/signal.c
index 41f9b91db209..70680dd8b588 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -505,13 +505,15 @@ flush_signal_handlers(struct task_struct *t, int force_default)
 	}
 }
 
-int unhandled_signal(struct task_struct *tsk, int sig)
+bool unhandled_signal(struct task_struct *tsk, int sig)
 {
 	void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler;
 	if (is_global_init(tsk))
-		return 1;
+		return true;
+
 	if (handler != SIG_IGN && handler != SIG_DFL)
-		return 0;
+		return false;
+
 	/* if ptraced, let the tracer determine */
 	return !tsk->ptrace;
 }
-- 
2.17.0

[PATCH v3 13/17] signal: make flush_sigqueue_mask() void

[Christian Brauner]

The return value of flush_sigqueue_mask() is never checked anywhere.

Signed-off-by: Christian Brauner <christian@brauner.io>
---
v2->v3:
* unchanged
v1->v2:
* unchanged
v0->v1:
* patch added
---
 kernel/signal.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/kernel/signal.c b/kernel/signal.c
index 70680dd8b588..100f2cb29fd8 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -687,14 +687,14 @@ void signal_wake_up_state(struct task_struct *t, unsigned int state)
  *
  * All callers must be holding the siglock.
  */
-static int flush_sigqueue_mask(sigset_t *mask, struct sigpending *s)
+static void flush_sigqueue_mask(sigset_t *mask, struct sigpending *s)
 {
 	struct sigqueue *q, *n;
 	sigset_t m;
 
 	sigandsets(&m, mask, &s->signal);
 	if (sigisemptyset(&m))
-		return 0;
+		return;
 
 	sigandnsets(&s->signal, &s->signal, mask);
 	list_for_each_entry_safe(q, n, &s->list, list) {
@@ -703,7 +703,6 @@ static int flush_sigqueue_mask(sigset_t *mask, struct sigpending *s)
 			__sigqueue_free(q);
 		}
 	}
-	return 1;
 }
 
 static inline int is_si_special(const struct siginfo *info)
-- 
2.17.0

[PATCH v3 14/17] signal: make wants_signal() return bool

[Christian Brauner]

wants_signal() already behaves like a boolean function. Let's actually
declare it as such too.

Signed-off-by: Christian Brauner <christian@brauner.io>
---
v2->v3:
* unchanged
v1->v2:
* unchanged
v0->v1:
* patch added
---
 kernel/signal.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/kernel/signal.c b/kernel/signal.c
index 100f2cb29fd8..3a12d3b25584 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -879,16 +879,20 @@ static bool prepare_signal(int sig, struct task_struct *p, bool force)
  * as soon as they're available, so putting the signal on the shared queue
  * will be equivalent to sending it to one such thread.
  */
-static inline int wants_signal(int sig, struct task_struct *p)
+static inline bool wants_signal(int sig, struct task_struct *p)
 {
 	if (sigismember(&p->blocked, sig))
-		return 0;
+		return false;
+
 	if (p->flags & PF_EXITING)
-		return 0;
+		return false;
+
 	if (sig == SIGKILL)
-		return 1;
+		return true;
+
 	if (task_is_stopped_or_traced(p))
-		return 0;
+		return false;
+
 	return task_curr(p) || !signal_pending(p);
 }
 
-- 
2.17.0

[PATCH v3 15/17] signal: make legacy_queue() return bool

[Christian Brauner]

legacy_queue() already behaves like a boolean function. Let's actually
declare it as such too.

Signed-off-by: Christian Brauner <christian@brauner.io>
---
v2->v3:
* unchanged
v1->v2:
* unchanged
v0->v1:
* patch added
---
 kernel/signal.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/signal.c b/kernel/signal.c
index 3a12d3b25584..50255b6a3124 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -972,7 +972,7 @@ static void complete_signal(int sig, struct task_struct *p, int group)
 	return;
 }
 
-static inline int legacy_queue(struct sigpending *signals, int sig)
+static inline bool legacy_queue(struct sigpending *signals, int sig)
 {
 	return (sig < SIGRTMIN) && sigismember(&signals->signal, sig);
 }
-- 
2.17.0

[PATCH v3 16/17] signal: make sigkill_pending() return bool

[Christian Brauner]

sigkill_pending() already behaves like a boolean function. Let's actually
declare it as such too.

Signed-off-by: Christian Brauner <christian@brauner.io>
---
v2->v3:
* [Oleg Nestorov] fix wrong function name in commit message
v1->v2:
* unchanged
v0->v1:
* patch added
---
 kernel/signal.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/signal.c b/kernel/signal.c
index 50255b6a3124..8d57a64abe52 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1918,10 +1918,10 @@ static inline bool may_ptrace_stop(void)
  * Return non-zero if there is a SIGKILL that should be waking us up.
  * Called with the siglock held.
  */
-static int sigkill_pending(struct task_struct *tsk)
+static bool sigkill_pending(struct task_struct *tsk)
 {
-	return	sigismember(&tsk->pending.signal, SIGKILL) ||
-		sigismember(&tsk->signal->shared_pending.signal, SIGKILL);
+	return sigismember(&tsk->pending.signal, SIGKILL) ||
+	       sigismember(&tsk->signal->shared_pending.signal, SIGKILL);
 }
 
 /*
-- 
2.17.0

[PATCH v3 17/17] signal: make get_signal() return bool

[Christian Brauner]

make get_signal() already behaves like a boolean function. Let's actually
declare it as such too.

Signed-off-by: Christian Brauner <christian@brauner.io>
---
v2->v3:
* unchanged
v1->v2:
* unchanged
v0->v1:
* patch added
---
 include/linux/signal.h | 2 +-
 kernel/signal.c        | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/include/linux/signal.h b/include/linux/signal.h
index 1145d7061ed9..97d5ff809716 100644
--- a/include/linux/signal.h
+++ b/include/linux/signal.h
@@ -262,7 +262,7 @@ extern void set_current_blocked(sigset_t *);
 extern void __set_current_blocked(const sigset_t *);
 extern int show_unhandled_signals;
 
-extern int get_signal(struct ksignal *ksig);
+extern bool get_signal(struct ksignal *ksig);
 extern void signal_setup_done(int failed, struct ksignal *ksig, int stepping);
 extern void exit_signals(struct task_struct *tsk);
 extern void kernel_sigaction(int, __sighandler_t);
diff --git a/kernel/signal.c b/kernel/signal.c
index 8d57a64abe52..47d0e3a9b166 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2301,7 +2301,7 @@ static int ptrace_signal(int signr, siginfo_t *info)
 	return signr;
 }
 
-int get_signal(struct ksignal *ksig)
+bool get_signal(struct ksignal *ksig)
 {
 	struct sighand_struct *sighand = current->sighand;
 	struct signal_struct *signal = current->signal;
@@ -2311,7 +2311,7 @@ int get_signal(struct ksignal *ksig)
 		task_work_run();
 
 	if (unlikely(uprobe_deny_signal()))
-		return 0;
+		return false;
 
 	/*
 	 * Do this once, we can't return to user-mode if freezing() == T.
-- 
2.17.0