v4.19.13 snapshot.
diff --git a/fs/xfs/libxfs/xfs_bit.c b/fs/xfs/libxfs/xfs_bit.c
new file mode 100644
index 0000000..40ce5f3
--- /dev/null
+++ b/fs/xfs/libxfs/xfs_bit.c
@@ -0,0 +1,106 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2000-2005 Silicon Graphics, Inc.
+ * All Rights Reserved.
+ */
+#include "xfs.h"
+#include "xfs_log_format.h"
+#include "xfs_bit.h"
+
+/*
+ * XFS bit manipulation routines, used in non-realtime code.
+ */
+
+/*
+ * Return whether bitmap is empty.
+ * Size is number of words in the bitmap, which is padded to word boundary
+ * Returns 1 for empty, 0 for non-empty.
+ */
+int
+xfs_bitmap_empty(uint *map, uint size)
+{
+ uint i;
+
+ for (i = 0; i < size; i++) {
+ if (map[i] != 0)
+ return 0;
+ }
+
+ return 1;
+}
+
+/*
+ * Count the number of contiguous bits set in the bitmap starting with bit
+ * start_bit. Size is the size of the bitmap in words.
+ */
+int
+xfs_contig_bits(uint *map, uint size, uint start_bit)
+{
+ uint * p = ((unsigned int *) map) + (start_bit >> BIT_TO_WORD_SHIFT);
+ uint result = 0;
+ uint tmp;
+
+ size <<= BIT_TO_WORD_SHIFT;
+
+ ASSERT(start_bit < size);
+ size -= start_bit & ~(NBWORD - 1);
+ start_bit &= (NBWORD - 1);
+ if (start_bit) {
+ tmp = *p++;
+ /* set to one first offset bits prior to start */
+ tmp |= (~0U >> (NBWORD-start_bit));
+ if (tmp != ~0U)
+ goto found;
+ result += NBWORD;
+ size -= NBWORD;
+ }
+ while (size) {
+ if ((tmp = *p++) != ~0U)
+ goto found;
+ result += NBWORD;
+ size -= NBWORD;
+ }
+ return result - start_bit;
+found:
+ return result + ffz(tmp) - start_bit;
+}
+
+/*
+ * This takes the bit number to start looking from and
+ * returns the next set bit from there. It returns -1
+ * if there are no more bits set or the start bit is
+ * beyond the end of the bitmap.
+ *
+ * Size is the number of words, not bytes, in the bitmap.
+ */
+int xfs_next_bit(uint *map, uint size, uint start_bit)
+{
+ uint * p = ((unsigned int *) map) + (start_bit >> BIT_TO_WORD_SHIFT);
+ uint result = start_bit & ~(NBWORD - 1);
+ uint tmp;
+
+ size <<= BIT_TO_WORD_SHIFT;
+
+ if (start_bit >= size)
+ return -1;
+ size -= result;
+ start_bit &= (NBWORD - 1);
+ if (start_bit) {
+ tmp = *p++;
+ /* set to zero first offset bits prior to start */
+ tmp &= (~0U << start_bit);
+ if (tmp != 0U)
+ goto found;
+ result += NBWORD;
+ size -= NBWORD;
+ }
+ while (size) {
+ if ((tmp = *p++) != 0U)
+ goto found;
+ result += NBWORD;
+ size -= NBWORD;
+ }
+ return -1;
+found:
+ return result + ffs(tmp) - 1;
+}