1 files changed, 41 insertions, 0 deletions
diff --git a/include/linux/blockgroup_lock.h b/include/linux/blockgroup_lock.h
new file mode 100644
index 000000000..511ab123a
--- /dev/null
+++ b/include/linux/blockgroup_lock.h
@@ -0,0 +1,41 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_BLOCKGROUP_LOCK_H
+#define _LINUX_BLOCKGROUP_LOCK_H
+/*
+ * Per-blockgroup locking for ext2 and ext3.
+ *
+ * Simple hashed spinlocking.
+ */
+
+#include <linux/spinlock.h>
+#include <linux/cache.h>
+
+#ifdef CONFIG_SMP
+#define NR_BG_LOCKS	(4 << ilog2(NR_CPUS < 32 ? NR_CPUS : 32))
+#else
+#define NR_BG_LOCKS	1
+#endif
+
+struct bgl_lock {
+	spinlock_t lock;
+} ____cacheline_aligned_in_smp;
+
+struct blockgroup_lock {
+	struct bgl_lock locks[NR_BG_LOCKS];
+};
+
+static inline void bgl_lock_init(struct blockgroup_lock *bgl)
+{
+	int i;
+
+	for (i = 0; i < NR_BG_LOCKS; i++)
+		spin_lock_init(&bgl->locks[i].lock);
+}
+
+static inline spinlock_t *
+bgl_lock_ptr(struct blockgroup_lock *bgl, unsigned int block_group)
+{
+	return &bgl->locks[block_group & (NR_BG_LOCKS-1)].lock;
+}
+
+#endif