[tip: sched/core] sched: Add get_current_state()

["tip-bot2 for Peter Zijlstra" <tip-bot2@linutronix.de>]

The following commit has been merged into the sched/core branch of tip:

Commit-ID:     d6c23bb3a2ad2f8f7dd46292b8bc54d27f2fb3f1
Gitweb:        https://git.kernel.org/tip/d6c23bb3a2ad2f8f7dd46292b8bc54d27f2fb3f1
Author:        Peter Zijlstra <peterz@infradead.org>
AuthorDate:    Fri, 11 Jun 2021 10:28:14 +02:00
Committer:     Peter Zijlstra <peterz@infradead.org>
CommitterDate: Fri, 18 Jun 2021 11:43:08 +02:00

sched: Add get_current_state()

Remove yet another few p->state accesses.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20210611082838.347475156@infradead.org
---
 block/blk-mq.c        | 2 +-
 include/linux/sched.h | 2 ++
 kernel/freezer.c      | 2 +-
 kernel/sched/core.c   | 6 +++---
 4 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 655db5f..56270bb 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -3910,7 +3910,7 @@ int blk_poll(struct request_queue *q, blk_qc_t cookie, bool spin)
 
 	hctx->poll_considered++;
 
-	state = current->state;
+	state = get_current_state();
 	do {
 		int ret;
 
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 2cd5635..395c890 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -213,6 +213,8 @@ struct task_group;
 
 #endif
 
+#define get_current_state()	READ_ONCE(current->state)
+
 /* Task command name length: */
 #define TASK_COMM_LEN			16
 
diff --git a/kernel/freezer.c b/kernel/freezer.c
index dc520f0..45ab36f 100644
--- a/kernel/freezer.c
+++ b/kernel/freezer.c
@@ -58,7 +58,7 @@ bool __refrigerator(bool check_kthr_stop)
 	/* Hmm, should we be allowed to suspend when there are realtime
 	   processes around? */
 	bool was_frozen = false;
-	long save = current->state;
+	unsigned int save = get_current_state();
 
 	pr_debug("%s entered refrigerator\n", current->comm);
 
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 618c2b5..45ebb3c 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -9098,15 +9098,15 @@ static inline int preempt_count_equals(int preempt_offset)
 
 void __might_sleep(const char *file, int line, int preempt_offset)
 {
+	unsigned int state = get_current_state();
 	/*
 	 * Blocking primitives will set (and therefore destroy) current->state,
 	 * since we will exit with TASK_RUNNING make sure we enter with it,
 	 * otherwise we will destroy state.
 	 */
-	WARN_ONCE(current->state != TASK_RUNNING && current->task_state_change,
+	WARN_ONCE(state != TASK_RUNNING && current->task_state_change,
 			"do not call blocking ops when !TASK_RUNNING; "
-			"state=%lx set at [<%p>] %pS\n",
-			current->state,
+			"state=%x set at [<%p>] %pS\n", state,
 			(void *)current->task_state_change,
 			(void *)current->task_state_change);