Hi Shaohua,

[auto build test WARNING on block/for-next]
[also build test WARNING on next-20161215]
[cannot apply to v4.9]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Shaohua-Li/blk-throttle-add-low-limit/20161216-093257
base:   https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git for-next
config: i386-randconfig-s0-201650 (attached as .config)
compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

All warnings (new ones prefixed by >>):

   block/blk-stat.c: In function 'blk_stat_set_issue':
>> block/blk-stat.c:243:26: warning: left shift count >= width of type [-Wshift-count-overflow]
      (blk_capped_size(size) << BLK_STAT_SIZE_SHIFT);
                             ^~

vim +243 block/blk-stat.c

   227			queue_for_each_hw_ctx(q, hctx, i) {
   228				hctx_for_each_ctx(hctx, ctx, j) {
   229					blk_stat_init(&ctx->stat[BLK_STAT_READ]);
   230					blk_stat_init(&ctx->stat[BLK_STAT_WRITE]);
   231				}
   232			}
   233		} else {
   234			blk_stat_init(&q->rq_stats[BLK_STAT_READ]);
   235			blk_stat_init(&q->rq_stats[BLK_STAT_WRITE]);
   236		}
   237	}
   238	
   239	void blk_stat_set_issue(struct blk_issue_stat *stat, sector_t size)
   240	{
   241		stat->stat = (stat->stat & BLK_STAT_RES_MASK) |
   242			(ktime_to_ns(ktime_get()) & BLK_STAT_TIME_MASK) |
 > 243			(blk_capped_size(size) << BLK_STAT_SIZE_SHIFT);
   244	}
   245	
   246	/*
   247	 * Enable stat tracking, return whether it was enabled
   248	 */
   249	bool blk_stat_enable(struct request_queue *q)
   250	{
   251		if (!test_bit(QUEUE_FLAG_STATS, &q->queue_flags)) {

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