bcachefs: Fix check for if extent update is allocating

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

1 files changed, 25 insertions, 0 deletions

diff --git a/fs/bcachefs/util.c b/fs/bcachefs/util.c
index 9f3eafb3e0d4..295f4577e9c1 100644
--- a/fs/bcachefs/util.c
+++ b/fs/bcachefs/util.c
@@ -904,3 +904,28 @@ void eytzinger0_find_test(void)
 	kfree(test_array);
 }
 #endif
+
+/*
+ * Accumulate percpu counters onto one cpu's copy - only valid when access
+ * against any percpu counter is guarded against
+ */
+u64 *bch2_acc_percpu_u64s(u64 __percpu *p, unsigned nr)
+{
+	u64 *ret;
+	int cpu;
+
+	preempt_disable();
+	ret = this_cpu_ptr(p);
+	preempt_enable();
+
+	for_each_possible_cpu(cpu) {
+		u64 *i = per_cpu_ptr(p, cpu);
+
+		if (i != ret) {
+			acc_u64s(ret, i, nr);
+			memset(i, 0, nr * sizeof(u64));
+		}
+	}
+
+	return ret;
+}