scsi: sbitmap: Add sbitmap_calculate_shift() helper
Move code for calculating default shift into a public helper which can be
used by SCSI.
Link: https://lore.kernel.org/r/[email protected]
Cc: Omar Sandoval <[email protected]>
Cc: Kashyap Desai <[email protected]>
Cc: Sumanesh Samanta <[email protected]>
Cc: Ewan D. Milne <[email protected]>
Tested-by: Sumanesh Samanta <[email protected]>
Reviewed-by: Hannes Reinecke <[email protected]>
Signed-off-by: Ming Lei <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>
diff --git a/lib/sbitmap.c b/lib/sbitmap.c
index 73da26a..47b3691 100644
--- a/lib/sbitmap.c
+++ b/lib/sbitmap.c
@@ -87,19 +87,9 @@ int sbitmap_init_node(struct sbitmap *sb, unsigned int depth, int shift,
unsigned int bits_per_word;
unsigned int i;
- if (shift < 0) {
- shift = ilog2(BITS_PER_LONG);
- /*
- * If the bitmap is small, shrink the number of bits per word so
- * we spread over a few cachelines, at least. If less than 4
- * bits, just forget about it, it's not going to work optimally
- * anyway.
- */
- if (depth >= 4) {
- while ((4U << shift) > depth)
- shift--;
- }
- }
+ if (shift < 0)
+ shift = sbitmap_calculate_shift(depth);
+
bits_per_word = 1U << shift;
if (bits_per_word > BITS_PER_LONG)
return -EINVAL;
