Revert "blk-mq: balance mapping between present CPUs and queues"

to #28991349

This reverts commit a3d72a0c79fac0e113bbeb85e1e19b3b3568e2f5.

Previously we just backported this patch partly, now we revert
it temporarily and will backport it in later patches formally.
Signed-off-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Reviewed-by: NJoseph Qi <joseph.qi@linux.alibaba.com>

block/blk-mq-cpumap.c

@@ -14,9 +14,9 @@
 #include "blk.h"
 #include "blk-mq.h"
 
-static int queue_index(unsigned int nr_queues, const int q)
+static int cpu_to_queue_index(unsigned int nr_queues, const int cpu)
 {
-	return q % nr_queues;
+	return cpu % nr_queues;
 }
 
 static int get_first_sibling(unsigned int cpu)
@@ -34,24 +34,9 @@ int blk_mq_map_queues(struct blk_mq_tag_set *set)
 {
 	unsigned int *map = set->mq_map;
 	unsigned int nr_queues = set->nr_hw_queues;
-	unsigned int cpu, first_sibling, q = 0;
-
-	for_each_possible_cpu(cpu)
-		map[cpu] = -1;
-
-	/*
-	 * Spread queues among present CPUs first for minimizing
-	 * count of dead queues which are mapped by all un-present CPUs
-	 */
-	for_each_present_cpu(cpu) {
-		if (q >= nr_queues)
-			break;
-		map[cpu] = queue_index(nr_queues, q++);
-	}
+	unsigned int cpu, first_sibling;
 
 	for_each_possible_cpu(cpu) {
-		if (map[cpu] != -1)
-			continue;
 		/*
 		 * First do sequential mapping between CPUs and queues.
 		 * In case we still have CPUs to map, and we have some number of
@@ -59,11 +44,11 @@ int blk_mq_map_queues(struct blk_mq_tag_set *set)
 		 * performace optimizations.
 		 */
 		if (cpu < nr_queues) {
-			map[cpu] = queue_index(nr_queues, q++);
+			map[cpu] = cpu_to_queue_index(nr_queues, cpu);
 		} else {
 			first_sibling = get_first_sibling(cpu);
 			if (first_sibling == cpu)
-				map[cpu] = queue_index(nr_queues, q++);
+				map[cpu] = cpu_to_queue_index(nr_queues, cpu);
 			else
 				map[cpu] = map[first_sibling];
 		}