[PATCH 27/34] sched_ext: Convert scx_dump_state() spinlock to raw spinlock

[Tejun Heo]

The scx_dump_state() function uses a regular spinlock to serialize
access. In a subsequent patch, this function will be called while
holding scx_sched_lock, which is a raw spinlock, creating a lock
nesting violation.

Convert the dump_lock to a raw spinlock and use the guard macro for
cleaner lock management.

Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
---
 kernel/sched/ext.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c
index e34896a57780..e8d7ad0a8a6b 100644
--- a/kernel/sched/ext.c
+++ b/kernel/sched/ext.c
@@ -5014,7 +5014,7 @@ static void scx_dump_task(struct seq_buf *s, struct scx_dump_ctx *dctx,
 
 static void scx_dump_state(struct scx_exit_info *ei, size_t dump_len)
 {
-	static DEFINE_SPINLOCK(dump_lock);
+	static DEFINE_RAW_SPINLOCK(dump_lock);
 	static const char trunc_marker[] = "\n\n~~~~ TRUNCATED ~~~~\n";
 	struct scx_sched *sch = scx_root;
 	struct scx_dump_ctx dctx = {
@@ -5026,11 +5026,10 @@ static void scx_dump_state(struct scx_exit_info *ei, size_t dump_len)
 	};
 	struct seq_buf s;
 	struct scx_event_stats events;
-	unsigned long flags;
 	char *buf;
 	int cpu;
 
-	spin_lock_irqsave(&dump_lock, flags);
+	guard(raw_spinlock_irqsave)(&dump_lock);
 
 	seq_buf_init(&s, ei->dump, dump_len);
 
@@ -5155,8 +5154,6 @@ static void scx_dump_state(struct scx_exit_info *ei, size_t dump_len)
 	if (seq_buf_has_overflowed(&s) && dump_len >= sizeof(trunc_marker))
 		memcpy(ei->dump + dump_len - sizeof(trunc_marker),
 		       trunc_marker, sizeof(trunc_marker));
-
-	spin_unlock_irqrestore(&dump_lock, flags);
 }
 
 static void scx_error_irq_workfn(struct irq_work *irq_work)
-- 
2.52.0