sched: Introduce task_is_running()

Peter Zijlstra · Peter Zijlstra · commit b03fbd4ff24c · 2021-06-18T11:43:07.000+02:00
Replace a bunch of 'p->state == TASK_RUNNING' with a new helper: task_is_running(p). Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Davidlohr Bueso <dave@stgolabs.net> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Acked-by: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20210611082838.222401495@infradead.org
diff --git a/arch/alpha/kernel/process.c b/arch/alpha/kernel/process.c
@@ -380,7 +380,7 @@ get_wchan(struct task_struct *p)
 {
 	unsigned long schedule_frame;
 	unsigned long pc;
-	if (!p || p == current || p->state == TASK_RUNNING)
+	if (!p || p == current || task_is_running(p))
 		return 0;
 	/*
 	 * This one depends on the frame size of schedule().  Do a
diff --git a/arch/arc/kernel/stacktrace.c b/arch/arc/kernel/stacktrace.c
@@ -83,7 +83,7 @@ seed_unwind_frame_info(struct task_struct *tsk, struct pt_regs *regs,
 		 *    is safe-kept and BLINK at a well known location in there
 		 */
 
-		if (tsk->state == TASK_RUNNING)
+		if (task_is_running(tsk))
 			return -1;
 
 		frame_info->task = tsk;
diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
@@ -288,7 +288,7 @@ unsigned long get_wchan(struct task_struct *p)
 	struct stackframe frame;
 	unsigned long stack_page;
 	int count = 0;
-	if (!p || p == current || p->state == TASK_RUNNING)
+	if (!p || p == current || task_is_running(p))
 		return 0;
 
 	frame.fp = thread_saved_fp(p);
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
@@ -598,7 +598,7 @@ unsigned long get_wchan(struct task_struct *p)
 	struct stackframe frame;
 	unsigned long stack_page, ret = 0;
 	int count = 0;
-	if (!p || p == current || p->state == TASK_RUNNING)
+	if (!p || p == current || task_is_running(p))
 		return 0;
 
 	stack_page = (unsigned long)try_get_task_stack(p);
diff --git a/arch/csky/kernel/stacktrace.c b/arch/csky/kernel/stacktrace.c
@@ -115,7 +115,7 @@ unsigned long get_wchan(struct task_struct *task)
 {
 	unsigned long pc = 0;
 
-	if (likely(task && task != current && task->state != TASK_RUNNING))
+	if (likely(task && task != current && !task_is_running(task)))
 		walk_stackframe(task, NULL, save_wchan, &pc);
 	return pc;
 }
diff --git a/arch/h8300/kernel/process.c b/arch/h8300/kernel/process.c
@@ -134,7 +134,7 @@ unsigned long get_wchan(struct task_struct *p)
 	unsigned long stack_page;
 	int count = 0;
 
-	if (!p || p == current || p->state == TASK_RUNNING)
+	if (!p || p == current || task_is_running(p))
 		return 0;
 
 	stack_page = (unsigned long)p;
diff --git a/arch/hexagon/kernel/process.c b/arch/hexagon/kernel/process.c
@@ -135,7 +135,7 @@ unsigned long get_wchan(struct task_struct *p)
 	unsigned long fp, pc;
 	unsigned long stack_page;
 	int count = 0;
-	if (!p || p == current || p->state == TASK_RUNNING)
+	if (!p || p == current || task_is_running(p))
 		return 0;
 
 	stack_page = (unsigned long)task_stack_page(p);
diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c
@@ -529,7 +529,7 @@ get_wchan (struct task_struct *p)
 	unsigned long ip;
 	int count = 0;
 
-	if (!p || p == current || p->state == TASK_RUNNING)
+	if (!p || p == current || task_is_running(p))
 		return 0;
 
 	/*
@@ -542,7 +542,7 @@ get_wchan (struct task_struct *p)
 	 */
 	unw_init_from_blocked_task(&info, p);
 	do {
-		if (p->state == TASK_RUNNING)
+		if (task_is_running(p))
 			return 0;
 		if (unw_unwind(&info) < 0)
 			return 0;
diff --git a/arch/m68k/kernel/process.c b/arch/m68k/kernel/process.c
@@ -268,7 +268,7 @@ unsigned long get_wchan(struct task_struct *p)
 	unsigned long fp, pc;
 	unsigned long stack_page;
 	int count = 0;
-	if (!p || p == current || p->state == TASK_RUNNING)
+	if (!p || p == current || task_is_running(p))
 		return 0;
 
 	stack_page = (unsigned long)task_stack_page(p);
diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
@@ -662,7 +662,7 @@ unsigned long get_wchan(struct task_struct *task)
 	unsigned long ra = 0;
 #endif
 
-	if (!task || task == current || task->state == TASK_RUNNING)
+	if (!task || task == current || task_is_running(task))
 		goto out;
 	if (!task_stack_page(task))
 		goto out;
diff --git a/arch/nds32/kernel/process.c b/arch/nds32/kernel/process.c
@@ -239,7 +239,7 @@ unsigned long get_wchan(struct task_struct *p)
 	unsigned long stack_start, stack_end;
 	int count = 0;
 
-	if (!p || p == current || p->state == TASK_RUNNING)
+	if (!p || p == current || task_is_running(p))
 		return 0;
 
 	if (IS_ENABLED(CONFIG_FRAME_POINTER)) {
diff --git a/arch/nios2/kernel/process.c b/arch/nios2/kernel/process.c
@@ -223,7 +223,7 @@ unsigned long get_wchan(struct task_struct *p)
 	unsigned long stack_page;
 	int count = 0;
 
-	if (!p || p == current || p->state == TASK_RUNNING)
+	if (!p || p == current || task_is_running(p))
 		return 0;
 
 	stack_page = (unsigned long)p;
diff --git a/arch/parisc/kernel/process.c b/arch/parisc/kernel/process.c
@@ -249,7 +249,7 @@ get_wchan(struct task_struct *p)
 	unsigned long ip;
 	int count = 0;
 
-	if (!p || p == current || p->state == TASK_RUNNING)
+	if (!p || p == current || task_is_running(p))
 		return 0;
 
 	/*
@@ -260,7 +260,7 @@ get_wchan(struct task_struct *p)
 	do {
 		if (unwind_once(&info) < 0)
 			return 0;
-		if (p->state == TASK_RUNNING)
+		if (task_is_running(p))
                         return 0;
 		ip = info.ip;
 		if (!in_sched_functions(ip))
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
@@ -2084,7 +2084,7 @@ static unsigned long __get_wchan(struct task_struct *p)
 	unsigned long ip, sp;
 	int count = 0;
 
-	if (!p || p == current || p->state == TASK_RUNNING)
+	if (!p || p == current || task_is_running(p))
 		return 0;
 
 	sp = p->thread.ksp;
@@ -2094,7 +2094,7 @@ static unsigned long __get_wchan(struct task_struct *p)
 	do {
 		sp = *(unsigned long *)sp;
 		if (!validate_sp(sp, p, STACK_FRAME_OVERHEAD) ||
-		    p->state == TASK_RUNNING)
+		    task_is_running(p))
 			return 0;
 		if (count > 0) {
 			ip = ((unsigned long *)sp)[STACK_FRAME_LR_SAVE];
diff --git a/arch/riscv/kernel/stacktrace.c b/arch/riscv/kernel/stacktrace.c
@@ -132,7 +132,7 @@ unsigned long get_wchan(struct task_struct *task)
 {
 	unsigned long pc = 0;
 
-	if (likely(task && task != current && task->state != TASK_RUNNING))
+	if (likely(task && task != current && !task_is_running(task)))
 		walk_stackframe(task, NULL, save_wchan, &pc);
 	return pc;
 }
diff --git a/arch/s390/kernel/process.c b/arch/s390/kernel/process.c
@@ -180,7 +180,7 @@ unsigned long get_wchan(struct task_struct *p)
 	struct unwind_state state;
 	unsigned long ip = 0;
 
-	if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p))
+	if (!p || p == current || task_is_running(p) || !task_stack_page(p))
 		return 0;
 
 	if (!try_get_task_stack(p))
diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
@@ -702,7 +702,7 @@ static void pfault_interrupt(struct ext_code ext_code,
 			 * interrupt since it must be a leftover of a PFAULT
 			 * CANCEL operation which didn't remove all pending
 			 * completion interrupts. */
-			if (tsk->state == TASK_RUNNING)
+			if (task_is_running(tsk))
 				tsk->thread.pfault_wait = -1;
 		}
 	} else {
diff --git a/arch/sh/kernel/process_32.c b/arch/sh/kernel/process_32.c
@@ -186,7 +186,7 @@ unsigned long get_wchan(struct task_struct *p)
 {
 	unsigned long pc;
 
-	if (!p || p == current || p->state == TASK_RUNNING)
+	if (!p || p == current || task_is_running(p))
 		return 0;
 
 	/*
diff --git a/arch/sparc/kernel/process_32.c b/arch/sparc/kernel/process_32.c
@@ -376,8 +376,7 @@ unsigned long get_wchan(struct task_struct *task)
 	struct reg_window32 *rw;
 	int count = 0;
 
-	if (!task || task == current ||
-            task->state == TASK_RUNNING)
+	if (!task || task == current || task_is_running(task))
 		goto out;
 
 	fp = task_thread_info(task)->ksp + bias;
diff --git a/arch/sparc/kernel/process_64.c b/arch/sparc/kernel/process_64.c
@@ -674,8 +674,7 @@ unsigned long get_wchan(struct task_struct *task)
         unsigned long ret = 0;
 	int count = 0; 
 
-	if (!task || task == current ||
-            task->state == TASK_RUNNING)
+	if (!task || task == current || task_is_running(task))
 		goto out;
 
 	tp = task_thread_info(task);
diff --git a/arch/um/kernel/process.c b/arch/um/kernel/process.c
@@ -369,7 +369,7 @@ unsigned long get_wchan(struct task_struct *p)
 	unsigned long stack_page, sp, ip;
 	bool seen_sched = 0;
 
-	if ((p == NULL) || (p == current) || (p->state == TASK_RUNNING))
+	if ((p == NULL) || (p == current) || task_is_running(p))
 		return 0;
 
 	stack_page = (unsigned long) task_stack_page(p);
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
@@ -931,7 +931,7 @@ unsigned long get_wchan(struct task_struct *p)
 	unsigned long start, bottom, top, sp, fp, ip, ret = 0;
 	int count = 0;
 
-	if (p == current || p->state == TASK_RUNNING)
+	if (p == current || task_is_running(p))
 		return 0;
 
 	if (!try_get_task_stack(p))
@@ -975,7 +975,7 @@ unsigned long get_wchan(struct task_struct *p)
 			goto out;
 		}
 		fp = READ_ONCE_NOCHECK(*(unsigned long *)fp);
-	} while (count++ < 16 && p->state != TASK_RUNNING);
+	} while (count++ < 16 && !task_is_running(p));
 
 out:
 	put_task_stack(p);
diff --git a/arch/xtensa/kernel/process.c b/arch/xtensa/kernel/process.c
@@ -304,7 +304,7 @@ unsigned long get_wchan(struct task_struct *p)
 	unsigned long stack_page = (unsigned long) task_stack_page(p);
 	int count = 0;
 
-	if (!p || p == current || p->state == TASK_RUNNING)
+	if (!p || p == current || task_is_running(p))
 		return 0;
 
 	sp = p->thread.sp;
diff --git a/block/blk-mq.c b/block/blk-mq.c
@@ -3926,7 +3926,7 @@ int blk_poll(struct request_queue *q, blk_qc_t cookie, bool spin)
 		if (signal_pending_state(state, current))
 			__set_current_state(TASK_RUNNING);
 
-		if (current->state == TASK_RUNNING)
+		if (task_is_running(current))
 			return 1;
 		if (ret < 0 || !spin)
 			break;
diff --git a/include/linux/sched.h b/include/linux/sched.h
@@ -113,6 +113,8 @@ struct task_group;
 					 __TASK_TRACED | EXIT_DEAD | EXIT_ZOMBIE | \
 					 TASK_PARKED)
 
+#define task_is_running(task)		(READ_ONCE((task)->state) == TASK_RUNNING)
+
 #define task_is_traced(task)		((task->state & __TASK_TRACED) != 0)
 
 #define task_is_stopped(task)		((task->state & __TASK_STOPPED) != 0)
diff --git a/kernel/kcsan/report.c b/kernel/kcsan/report.c
@@ -460,7 +460,7 @@ static void set_other_info_task_blocking(unsigned long *flags,
 	 * We may be instrumenting a code-path where current->state is already
 	 * something other than TASK_RUNNING.
 	 */
-	const bool is_running = current->state == TASK_RUNNING;
+	const bool is_running = task_is_running(current);
 	/*
 	 * To avoid deadlock in case we are in an interrupt here and this is a
 	 * race with a task on the same CPU (KCSAN_INTERRUPT_WATCHER), provide a
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
@@ -760,7 +760,7 @@ static void lockdep_print_held_locks(struct task_struct *p)
 	 * It's not reliable to print a task's held locks if it's not sleeping
 	 * and it's not the current task.
 	 */
-	if (p->state == TASK_RUNNING && p != current)
+	if (p != current && task_is_running(p))
 		return;
 	for (i = 0; i < depth; i++) {
 		printk(" #%d: ", i);
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
@@ -2768,7 +2768,7 @@ EXPORT_SYMBOL_GPL(rcu_bind_current_to_nocb);
 #ifdef CONFIG_SMP
 static char *show_rcu_should_be_on_cpu(struct task_struct *tsp)
 {
-	return tsp && tsp->state == TASK_RUNNING && !tsp->on_cpu ? "!" : "";
+	return tsp && task_is_running(tsp) && !tsp->on_cpu ? "!" : "";
 }
 #else // #ifdef CONFIG_SMP
 static char *show_rcu_should_be_on_cpu(struct task_struct *tsp)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
@@ -5974,7 +5974,7 @@ static inline void sched_submit_work(struct task_struct *tsk)
 {
 	unsigned int task_flags;
 
-	if (!tsk->state)
+	if (task_is_running(tsk))
 		return;
 
 	task_flags = tsk->flags;
@@ -7949,7 +7949,7 @@ int __sched yield_to(struct task_struct *p, bool preempt)
 	if (curr->sched_class != p->sched_class)
 		goto out_unlock;
 
-	if (task_running(p_rq, p) || p->state)
+	if (task_running(p_rq, p) || !task_is_running(p))
 		goto out_unlock;
 
 	yielded = curr->sched_class->yield_to_task(rq, p);
@@ -8152,7 +8152,7 @@ void sched_show_task(struct task_struct *p)
 
 	pr_info("task:%-15.15s state:%c", p->comm, task_state_to_char(p));
 
-	if (p->state == TASK_RUNNING)
+	if (task_is_running(p))
 		pr_cont("  running task    ");
 #ifdef CONFIG_DEBUG_STACK_USAGE
 	free = stack_not_used(p);
diff --git a/kernel/sched/stats.h b/kernel/sched/stats.h
@@ -217,7 +217,7 @@ static inline void sched_info_depart(struct rq *rq, struct task_struct *t)
 
 	rq_sched_info_depart(rq, delta);
 
-	if (t->state == TASK_RUNNING)
+	if (task_is_running(t))
 		sched_info_enqueue(rq, t);
 }
 
diff --git a/kernel/signal.c b/kernel/signal.c
@@ -4719,7 +4719,7 @@ void kdb_send_sig(struct task_struct *t, int sig)
 	}
 	new_t = kdb_prev_t != t;
 	kdb_prev_t = t;
-	if (t->state != TASK_RUNNING && new_t) {
+	if (!task_is_running(t) && new_t) {
 		spin_unlock(&t->sighand->siglock);
 		kdb_printf("Process is not RUNNING, sending a signal from "
 			   "kdb risks deadlock\n"
diff --git a/kernel/softirq.c b/kernel/softirq.c
@@ -92,8 +92,7 @@ static bool ksoftirqd_running(unsigned long pending)
 
 	if (pending & SOFTIRQ_NOW_MASK)
 		return false;
-	return tsk && (tsk->state == TASK_RUNNING) &&
-		!__kthread_should_park(tsk);
+	return tsk && task_is_running(tsk) && !__kthread_should_park(tsk);
 }
 
 #ifdef CONFIG_TRACE_IRQFLAGS
diff --git a/mm/compaction.c b/mm/compaction.c
@@ -1955,7 +1955,7 @@ static inline bool is_via_compact_memory(int order)
 
 static bool kswapd_is_running(pg_data_t *pgdat)
 {
-	return pgdat->kswapd && (pgdat->kswapd->state == TASK_RUNNING);
+	return pgdat->kswapd && task_is_running(pgdat->kswapd);
 }
 
 /*

Original file line number	Diff line number	Diff line change
`@@ -380,7 +380,7 @@ get_wchan(struct task_struct *p)`
`380`	`380`	`{`
`381`	`381`	`unsigned long schedule_frame;`
`382`	`382`	`unsigned long pc;`
`383`		`- if (!p \|\| p == current \|\| p->state == TASK_RUNNING)`
	`383`	`+ if (!p \|\| p == current \|\| task_is_running(p))`
`384`	`384`	`return 0;`
`385`	`385`	`/*`
`386`	`386`	`* This one depends on the frame size of schedule(). Do a`
Original file line number	Diff line number	Diff line change
`@@ -115,7 +115,7 @@ unsigned long get_wchan(struct task_struct *task)`
`115`	`115`	`{`
`116`	`116`	`unsigned long pc = 0;`
`117`	`117`
`118`		`- if (likely(task && task != current && task->state != TASK_RUNNING))`
	`118`	`+ if (likely(task && task != current && !task_is_running(task)))`
`119`	`119`	`walk_stackframe(task, NULL, save_wchan, &pc);`
`120`	`120`	`return pc;`
`121`	`121`	`}`