bfq-iosched: remove unused variable

bfqd->sb_shift was attempted used as a cache for the sbitmap queue
shift, but we don't need it, as it never changes. Kill it with fire.

Acked-by: Paolo Valente <paolo.valente@linaro.org>
Reviewed-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 7 insertions, 9 deletions

diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index 0cd8aa80c32d..10294124d597 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -5085,26 +5085,24 @@ void bfq_put_async_queues(struct bfq_data *bfqd, struct bfq_group *bfqg)
  */
 static void bfq_update_depths(struct bfq_data *bfqd, struct sbitmap_queue *bt)
 {
-        bfqd->sb_shift = bt->sb.shift;
-
         /*
          * In-word depths if no bfq_queue is being weight-raised:
          * leaving 25% of tags only for sync reads.
          *
          * In next formulas, right-shift the value
-         * (1U<<bfqd->sb_shift), instead of computing directly
-         * (1U<<(bfqd->sb_shift - something)), to be robust against
-         * any possible value of bfqd->sb_shift, without having to
+         * (1U<<bt->sb.shift), instead of computing directly
+         * (1U<<(bt->sb.shift - something)), to be robust against
+         * any possible value of bt->sb.shift, without having to
          * limit 'something'.
          */
         /* no more than 50% of tags for async I/O */
-        bfqd->word_depths[0][0] = max((1U<<bfqd->sb_shift)>>1, 1U);
+        bfqd->word_depths[0][0] = max((1U << bt->sb.shift) >> 1, 1U);
         /*
          * no more than 75% of tags for sync writes (25% extra tags
          * w.r.t. async I/O, to prevent async I/O from starving sync
          * writes)
          */
-        bfqd->word_depths[0][1] = max(((1U<<bfqd->sb_shift) * 3)>>2, 1U);
+        bfqd->word_depths[0][1] = max(((1U << bt->sb.shift) * 3) >> 2, 1U);
 
         /*
          * In-word depths in case some bfq_queue is being weight-
@@ -5114,9 +5112,9 @@ static void bfq_update_depths(struct bfq_data *bfqd, struct sbitmap_queue *bt)
          * shortage.
          */
         /* no more than ~18% of tags for async I/O */
-        bfqd->word_depths[1][0] = max(((1U<<bfqd->sb_shift) * 3)>>4, 1U);
+        bfqd->word_depths[1][0] = max(((1U << bt->sb.shift) * 3) >> 4, 1U);
         /* no more than ~37% of tags for sync writes (~20% extra tags) */
-        bfqd->word_depths[1][1] = max(((1U<<bfqd->sb_shift) * 6)>>4, 1U);
+        bfqd->word_depths[1][1] = max(((1U << bt->sb.shift) * 6) >> 4, 1U);
 }
 
 static int bfq_init_hctx(struct blk_mq_hw_ctx *hctx, unsigned int index)