[10/11] rcutorture: Add srcu_read_lock_lite() support to rcutorture.reader_flavor

Commit Message

Paul E. McKenney Sept. 3, 2024, 4:33 p.m. UTC

This commit causes bit 0x4 of rcutorture.reader_flavor to select the new
srcu_read_lock_lite() and srcu_read_unlock_lite() functions.

Signed-off-by: Paul E. McKenney <[e-mail]>
Cc: Alexei Starovoitov <[e-mail]>
Cc: Andrii Nakryiko <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Kent Overstreet <[e-mail]>
Cc: <[e-mail]>
---
 Documentation/admin-guide/kernel-parameters.txt | 4 ++--
 kernel/rcu/rcutorture.c                         | 7 +++++++
 2 files changed, 9 insertions(+), 2 deletions(-)

Patch

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index e107c82f0b21b..39bf8ce17e992 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -5357,8 +5357,8 @@ 
 			If there is more than one bit set, the readers
 			are entered from low-order bit up, and are
 			exited in the opposite order.  For SRCU, the
-			0x1 bit is normal readers and the 0x2 bit is
-			for NMI-safe readers.
+			0x1 bit is normal readers, 0x2 NMI-safe readers,
+			and 0x4 light-weight readers.
 
 	rcutorture.shuffle_interval= [KNL]
 			Set task-shuffle interval (s).  Shuffling tasks
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 1a3e0fdca7139..306a449bbad87 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -660,6 +660,11 @@  static int srcu_torture_read_lock(void)
 		WARN_ON_ONCE(idx & ~0x1);
 		ret += idx << 1;
 	}
+	if (reader_flavor & 0x4) {
+		idx = srcu_read_lock_lite(srcu_ctlp);
+		WARN_ON_ONCE(idx & ~0x1);
+		ret += idx << 2;
+	}
 	return ret;
 }
 
@@ -685,6 +690,8 @@  srcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp)
 static void srcu_torture_read_unlock(int idx)
 {
 	WARN_ON_ONCE((reader_flavor && (idx & ~reader_flavor)) || (!reader_flavor && (idx & ~0x1)));
+	if (reader_flavor & 0x4)
+		srcu_read_unlock_lite(srcu_ctlp, (idx & 0x4) >> 2);
 	if (reader_flavor & 0x2)
 		srcu_read_unlock_nmisafe(srcu_ctlp, (idx & 0x2) >> 1);
 	if ((reader_flavor & 0x1) || !(reader_flavor & 0x7))