locking/seqlock: Support Clang's context analysis

Add support for Clang's context analysis for seqlock_t.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251219154418.3592607-12-elver@google.com

1 files changed, 50 insertions, 0 deletions

diff --git a/lib/test_context-analysis.c b/lib/test_context-analysis.c
index 2b28d20c5f51..53abea0008f2 100644
--- a/lib/test_context-analysis.c
+++ b/lib/test_context-analysis.c
@@ -6,6 +6,7 @@
 
 #include <linux/build_bug.h>
 #include <linux/mutex.h>
+#include <linux/seqlock.h>
 #include <linux/spinlock.h>
 
 /*
@@ -208,3 +209,52 @@ static void __used test_mutex_cond_guard(struct test_mutex_data *d)
 		d->counter++;
 	}
 }
+
+struct test_seqlock_data {
+	seqlock_t sl;
+	int counter __guarded_by(&sl);
+};
+
+static void __used test_seqlock_init(struct test_seqlock_data *d)
+{
+	seqlock_init(&d->sl);
+	d->counter = 0;
+}
+
+static void __used test_seqlock_reader(struct test_seqlock_data *d)
+{
+	unsigned int seq;
+
+	do {
+		seq = read_seqbegin(&d->sl);
+		(void)d->counter;
+	} while (read_seqretry(&d->sl, seq));
+}
+
+static void __used test_seqlock_writer(struct test_seqlock_data *d)
+{
+	unsigned long flags;
+
+	write_seqlock(&d->sl);
+	d->counter++;
+	write_sequnlock(&d->sl);
+
+	write_seqlock_irq(&d->sl);
+	d->counter++;
+	write_sequnlock_irq(&d->sl);
+
+	write_seqlock_bh(&d->sl);
+	d->counter++;
+	write_sequnlock_bh(&d->sl);
+
+	write_seqlock_irqsave(&d->sl, flags);
+	d->counter++;
+	write_sequnlock_irqrestore(&d->sl, flags);
+}
+
+static void __used test_seqlock_scoped(struct test_seqlock_data *d)
+{
+	scoped_seqlock_read (&d->sl, ss_lockless) {
+		(void)d->counter;
+	}
+}