uint64_t latest = 0;
        int i, j, nr;
 
-       blk_stat_init(&dst[BLK_STAT_READ]);
-       blk_stat_init(&dst[BLK_STAT_WRITE]);
+       blk_stat_init(&dst[READ]);
+       blk_stat_init(&dst[WRITE]);
 
        nr = 0;
        do {
 
                queue_for_each_hw_ctx(q, hctx, i) {
                        hctx_for_each_ctx(hctx, ctx, j) {
-                               blk_stat_flush_batch(&ctx->stat[BLK_STAT_READ]);
-                               blk_stat_flush_batch(&ctx->stat[BLK_STAT_WRITE]);
+                               blk_stat_flush_batch(&ctx->stat[READ]);
+                               blk_stat_flush_batch(&ctx->stat[WRITE]);
 
-                               if (!ctx->stat[BLK_STAT_READ].nr_samples &&
-                                   !ctx->stat[BLK_STAT_WRITE].nr_samples)
+                               if (!ctx->stat[READ].nr_samples &&
+                                   !ctx->stat[WRITE].nr_samples)
                                        continue;
-                               if (ctx->stat[BLK_STAT_READ].time > newest)
-                                       newest = ctx->stat[BLK_STAT_READ].time;
-                               if (ctx->stat[BLK_STAT_WRITE].time > newest)
-                                       newest = ctx->stat[BLK_STAT_WRITE].time;
+                               if (ctx->stat[READ].time > newest)
+                                       newest = ctx->stat[READ].time;
+                               if (ctx->stat[WRITE].time > newest)
+                                       newest = ctx->stat[WRITE].time;
                        }
                }
 
 
                queue_for_each_hw_ctx(q, hctx, i) {
                        hctx_for_each_ctx(hctx, ctx, j) {
-                               if (ctx->stat[BLK_STAT_READ].time == newest) {
-                                       blk_stat_sum(&dst[BLK_STAT_READ],
-                                                    &ctx->stat[BLK_STAT_READ]);
+                               if (ctx->stat[READ].time == newest) {
+                                       blk_stat_sum(&dst[READ],
+                                                    &ctx->stat[READ]);
                                        nr++;
                                }
-                               if (ctx->stat[BLK_STAT_WRITE].time == newest) {
-                                       blk_stat_sum(&dst[BLK_STAT_WRITE],
-                                                    &ctx->stat[BLK_STAT_WRITE]);
+                               if (ctx->stat[WRITE].time == newest) {
+                                       blk_stat_sum(&dst[WRITE],
+                                                    &ctx->stat[WRITE]);
                                        nr++;
                                }
                        }
                 */
        } while (!nr);
 
-       dst[BLK_STAT_READ].time = dst[BLK_STAT_WRITE].time = latest;
+       dst[READ].time = dst[WRITE].time = latest;
 }
 
 void blk_queue_stat_get(struct request_queue *q, struct blk_rq_stat *dst)
        if (q->mq_ops)
                blk_mq_stat_get(q, dst);
        else {
-               blk_stat_flush_batch(&q->rq_stats[BLK_STAT_READ]);
-               blk_stat_flush_batch(&q->rq_stats[BLK_STAT_WRITE]);
-               memcpy(&dst[BLK_STAT_READ], &q->rq_stats[BLK_STAT_READ],
-                               sizeof(struct blk_rq_stat));
-               memcpy(&dst[BLK_STAT_WRITE], &q->rq_stats[BLK_STAT_WRITE],
-                               sizeof(struct blk_rq_stat));
+               blk_stat_flush_batch(&q->rq_stats[READ]);
+               blk_stat_flush_batch(&q->rq_stats[WRITE]);
+               memcpy(&dst[READ], &q->rq_stats[READ],
+                      sizeof(struct blk_rq_stat));
+               memcpy(&dst[WRITE], &q->rq_stats[WRITE],
+                      sizeof(struct blk_rq_stat));
        }
 }
 
                uint64_t newest = 0;
 
                hctx_for_each_ctx(hctx, ctx, i) {
-                       blk_stat_flush_batch(&ctx->stat[BLK_STAT_READ]);
-                       blk_stat_flush_batch(&ctx->stat[BLK_STAT_WRITE]);
+                       blk_stat_flush_batch(&ctx->stat[READ]);
+                       blk_stat_flush_batch(&ctx->stat[WRITE]);
 
-                       if (!ctx->stat[BLK_STAT_READ].nr_samples &&
-                           !ctx->stat[BLK_STAT_WRITE].nr_samples)
+                       if (!ctx->stat[READ].nr_samples &&
+                           !ctx->stat[WRITE].nr_samples)
                                continue;
 
-                       if (ctx->stat[BLK_STAT_READ].time > newest)
-                               newest = ctx->stat[BLK_STAT_READ].time;
-                       if (ctx->stat[BLK_STAT_WRITE].time > newest)
-                               newest = ctx->stat[BLK_STAT_WRITE].time;
+                       if (ctx->stat[READ].time > newest)
+                               newest = ctx->stat[READ].time;
+                       if (ctx->stat[WRITE].time > newest)
+                               newest = ctx->stat[WRITE].time;
                }
 
                if (!newest)
                        break;
 
                hctx_for_each_ctx(hctx, ctx, i) {
-                       if (ctx->stat[BLK_STAT_READ].time == newest) {
-                               blk_stat_sum(&dst[BLK_STAT_READ],
-                                               &ctx->stat[BLK_STAT_READ]);
+                       if (ctx->stat[READ].time == newest) {
+                               blk_stat_sum(&dst[READ], &ctx->stat[READ]);
                                nr++;
                        }
-                       if (ctx->stat[BLK_STAT_WRITE].time == newest) {
-                               blk_stat_sum(&dst[BLK_STAT_WRITE],
-                                               &ctx->stat[BLK_STAT_WRITE]);
+                       if (ctx->stat[WRITE].time == newest) {
+                               blk_stat_sum(&dst[WRITE], &ctx->stat[WRITE]);
                                nr++;
                        }
                }
 
                queue_for_each_hw_ctx(q, hctx, i) {
                        hctx_for_each_ctx(hctx, ctx, j) {
-                               blk_stat_init(&ctx->stat[BLK_STAT_READ]);
-                               blk_stat_init(&ctx->stat[BLK_STAT_WRITE]);
+                               blk_stat_init(&ctx->stat[READ]);
+                               blk_stat_init(&ctx->stat[WRITE]);
                        }
                }
        } else {
-               blk_stat_init(&q->rq_stats[BLK_STAT_READ]);
-               blk_stat_init(&q->rq_stats[BLK_STAT_WRITE]);
+               blk_stat_init(&q->rq_stats[READ]);
+               blk_stat_init(&q->rq_stats[WRITE]);
        }
 }
 
 
         * that it's writes impacting us, and not just some sole read on
         * a device that is in a lower power state.
         */
-       return stat[BLK_STAT_READ].nr_samples >= 1 &&
-               stat[BLK_STAT_WRITE].nr_samples >= RWB_MIN_WRITE_SAMPLES;
+       return (stat[READ].nr_samples >= 1 &&
+               stat[WRITE].nr_samples >= RWB_MIN_WRITE_SAMPLES);
 }
 
 static u64 rwb_sync_issue_lat(struct rq_wb *rwb)
         */
        thislat = rwb_sync_issue_lat(rwb);
        if (thislat > rwb->cur_win_nsec ||
-           (thislat > rwb->min_lat_nsec && !stat[BLK_STAT_READ].nr_samples)) {
+           (thislat > rwb->min_lat_nsec && !stat[READ].nr_samples)) {
                trace_wbt_lat(bdi, thislat);
                return LAT_EXCEEDED;
        }
                 * waited or still has writes in flights, consider us doing
                 * just writes as well.
                 */
-               if ((stat[BLK_STAT_WRITE].nr_samples && blk_stat_is_current(stat)) ||
+               if ((stat[WRITE].nr_samples && blk_stat_is_current(stat)) ||
                    wb_recent_wait(rwb) || wbt_inflight(rwb))
                        return LAT_UNKNOWN_WRITES;
                return LAT_UNKNOWN;
        /*
         * If the 'min' latency exceeds our target, step down.
         */
-       if (stat[BLK_STAT_READ].min > rwb->min_lat_nsec) {
-               trace_wbt_lat(bdi, stat[BLK_STAT_READ].min);
+       if (stat[READ].min > rwb->min_lat_nsec) {
+               trace_wbt_lat(bdi, stat[READ].min);
                trace_wbt_stat(bdi, stat);
                return LAT_EXCEEDED;
        }