blk-stat: fix a few cases of missing batch flushing

Everytime we need to read ->nr_samples, we should have flushed
the batch first. The non-mq read path also needs to flush the
batch.

Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/block/blk-stat.c b/block/blk-stat.c
index 4d0118568727ec2658742d27b8b8d8ff481ecdef..9b43efb8933fb9a0f352922029b86903e5b7c8e7 100644 (file)
--- a/block/blk-stat.c
+++ b/block/blk-stat.c
@@ -64,6 +64,9 @@ static void blk_mq_stat_get(struct request_queue *q, struct blk_rq_stat *dst)
 
                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]);
+
                                if (!ctx->stat[BLK_STAT_READ].nr_samples &&
                                    !ctx->stat[BLK_STAT_WRITE].nr_samples)
                                        continue;
@@ -111,6 +114,8 @@ 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],
@@ -128,6 +133,9 @@ void blk_hctx_stat_get(struct blk_mq_hw_ctx *hctx, struct blk_rq_stat *dst)
                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]);
+
                        if (!ctx->stat[BLK_STAT_READ].nr_samples &&
                            !ctx->stat[BLK_STAT_WRITE].nr_samples)
                                continue;