prlimit: make do_prlimit() static

There are no other callers in the kernel.

Fixed up a comment format and whitespace issue when moving do_prlimit()
higher in sys.c.
Signed-off-by: Barret Rhoden <brho@google.com>
Link: https://lkml.kernel.org/r/20220106172041.522167-3-brho@google.comSigned-off-by: Eric W. Biederman <ebiederm@xmission.com>

include/linux/resource.h

@@ -8,7 +8,5 @@
 struct task_struct;
 
 void getrusage(struct task_struct *p, int who, struct rusage *ru);
-int do_prlimit(struct task_struct *tsk, unsigned int resource,
-		struct rlimit *new_rlim, struct rlimit *old_rlim);
 
 #endif

kernel/sys.c

@@ -1424,6 +1424,65 @@ SYSCALL_DEFINE2(setdomainname, char __user *, name, int, len)
 	return errno;
 }
 
+/* make sure you are allowed to change @tsk limits before calling this */
+static int do_prlimit(struct task_struct *tsk, unsigned int resource,
+		      struct rlimit *new_rlim, struct rlimit *old_rlim)
+{
+	struct rlimit *rlim;
+	int retval = 0;
+
+	if (resource >= RLIM_NLIMITS)
+		return -EINVAL;
+	if (new_rlim) {
+		if (new_rlim->rlim_cur > new_rlim->rlim_max)
+			return -EINVAL;
+		if (resource == RLIMIT_NOFILE &&
+				new_rlim->rlim_max > sysctl_nr_open)
+			return -EPERM;
+	}
+
+	/* protect tsk->signal and tsk->sighand from disappearing */
+	read_lock(&tasklist_lock);
+	if (!tsk->sighand) {
+		retval = -ESRCH;
+		goto out;
+	}
+
+	rlim = tsk->signal->rlim + resource;
+	task_lock(tsk->group_leader);
+	if (new_rlim) {
+		/*
+		 * Keep the capable check against init_user_ns until cgroups can
+		 * contain all limits.
+		 */
+		if (new_rlim->rlim_max > rlim->rlim_max &&
+				!capable(CAP_SYS_RESOURCE))
+			retval = -EPERM;
+		if (!retval)
+			retval = security_task_setrlimit(tsk, resource, new_rlim);
+	}
+	if (!retval) {
+		if (old_rlim)
+			*old_rlim = *rlim;
+		if (new_rlim)
+			*rlim = *new_rlim;
+	}
+	task_unlock(tsk->group_leader);
+
+	/*
+	 * RLIMIT_CPU handling. Arm the posix CPU timer if the limit is not
+	 * infinite. In case of RLIM_INFINITY the posix CPU timer code
+	 * ignores the rlimit.
+	 */
+	if (!retval && new_rlim && resource == RLIMIT_CPU &&
+	    new_rlim->rlim_cur != RLIM_INFINITY &&
+	    IS_ENABLED(CONFIG_POSIX_TIMERS))
+		update_rlimit_cpu(tsk, new_rlim->rlim_cur);
+out:
+	read_unlock(&tasklist_lock);
+	return retval;
+}
+
 SYSCALL_DEFINE2(getrlimit, unsigned int, resource, struct rlimit __user *, rlim)
 {
 	struct rlimit value;
@@ -1567,63 +1626,6 @@ static void rlim64_to_rlim(const struct rlimit64 *rlim64, struct rlimit *rlim)
 		rlim->rlim_max = (unsigned long)rlim64->rlim_max;
 }
 
-/* make sure you are allowed to change @tsk limits before calling this */
-int do_prlimit(struct task_struct *tsk, unsigned int resource,
-		struct rlimit *new_rlim, struct rlimit *old_rlim)
-{
-	struct rlimit *rlim;
-	int retval = 0;
-
-	if (resource >= RLIM_NLIMITS)
-		return -EINVAL;
-	if (new_rlim) {
-		if (new_rlim->rlim_cur > new_rlim->rlim_max)
-			return -EINVAL;
-		if (resource == RLIMIT_NOFILE &&
-				new_rlim->rlim_max > sysctl_nr_open)
-			return -EPERM;
-	}
-
-	/* protect tsk->signal and tsk->sighand from disappearing */
-	read_lock(&tasklist_lock);
-	if (!tsk->sighand) {
-		retval = -ESRCH;
-		goto out;
-	}
-
-	rlim = tsk->signal->rlim + resource;
-	task_lock(tsk->group_leader);
-	if (new_rlim) {
-		/* Keep the capable check against init_user_ns until
-		   cgroups can contain all limits */
-		if (new_rlim->rlim_max > rlim->rlim_max &&
-				!capable(CAP_SYS_RESOURCE))
-			retval = -EPERM;
-		if (!retval)
-			retval = security_task_setrlimit(tsk, resource, new_rlim);
-	}
-	if (!retval) {
-		if (old_rlim)
-			*old_rlim = *rlim;
-		if (new_rlim)
-			*rlim = *new_rlim;
-	}
-	task_unlock(tsk->group_leader);
-
-	/*
-	 * RLIMIT_CPU handling. Arm the posix CPU timer if the limit is not
-	 * infinite. In case of RLIM_INFINITY the posix CPU timer code
-	 * ignores the rlimit.
-	 */
-	 if (!retval && new_rlim && resource == RLIMIT_CPU &&
-	     new_rlim->rlim_cur != RLIM_INFINITY &&
-	     IS_ENABLED(CONFIG_POSIX_TIMERS))
-		update_rlimit_cpu(tsk, new_rlim->rlim_cur);
-out:
-	read_unlock(&tasklist_lock);
-	return retval;
-}
-
 /* rcu lock must be held */
 static int check_prlimit_permission(struct task_struct *task,
 				    unsigned int flags)