v4.19.13 snapshot.
diff --git a/lib/bucket_locks.c b/lib/bucket_locks.c
new file mode 100644
index 0000000..64b92e1
--- /dev/null
+++ b/lib/bucket_locks.c
@@ -0,0 +1,54 @@
+#include <linux/export.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+
+/* Allocate an array of spinlocks to be accessed by a hash. Two arguments
+ * indicate the number of elements to allocate in the array. max_size
+ * gives the maximum number of elements to allocate. cpu_mult gives
+ * the number of locks per CPU to allocate. The size is rounded up
+ * to a power of 2 to be suitable as a hash table.
+ */
+
+int __alloc_bucket_spinlocks(spinlock_t **locks, unsigned int *locks_mask,
+ size_t max_size, unsigned int cpu_mult, gfp_t gfp,
+ const char *name, struct lock_class_key *key)
+{
+ spinlock_t *tlocks = NULL;
+ unsigned int i, size;
+#if defined(CONFIG_PROVE_LOCKING)
+ unsigned int nr_pcpus = 2;
+#else
+ unsigned int nr_pcpus = num_possible_cpus();
+#endif
+
+ if (cpu_mult) {
+ nr_pcpus = min_t(unsigned int, nr_pcpus, 64UL);
+ size = min_t(unsigned int, nr_pcpus * cpu_mult, max_size);
+ } else {
+ size = max_size;
+ }
+
+ if (sizeof(spinlock_t) != 0) {
+ tlocks = kvmalloc_array(size, sizeof(spinlock_t), gfp);
+ if (!tlocks)
+ return -ENOMEM;
+ for (i = 0; i < size; i++) {
+ spin_lock_init(&tlocks[i]);
+ lockdep_init_map(&tlocks[i].dep_map, name, key, 0);
+ }
+ }
+
+ *locks = tlocks;
+ *locks_mask = size - 1;
+
+ return 0;
+}
+EXPORT_SYMBOL(__alloc_bucket_spinlocks);
+
+void free_bucket_spinlocks(spinlock_t *locks)
+{
+ kvfree(locks);
+}
+EXPORT_SYMBOL(free_bucket_spinlocks);