From 12d319b920fa673a4d5e7c1785c5dc82dcd15257 Mon Sep 17 00:00:00 2001 From: Stefan Haberland Date: Fri, 12 Feb 2016 14:50:52 +0100 Subject: [PATCH] s390/dasd: fix performance drop Commit ca369d51b ("sd: Fix device-imposed transfer length limits") introduced a new queue limit max_dev_sectors which limits the maximum sectors for requests. The default value leads to small dasd requests and therefor to a performance drop. Set the max_dev_sectors value to the same value as the max_hw_sectors to use the maximum available request size for DASD devices. Signed-off-by: Stefan Haberland Cc: stable@vger.kernel.org # 4.4+ Signed-off-by: Martin Schwidefsky --- drivers/s390/block/dasd.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c index 41605dac8309..c78db05e75b1 100644 --- a/drivers/s390/block/dasd.c +++ b/drivers/s390/block/dasd.c @@ -3035,6 +3035,7 @@ static void dasd_setup_queue(struct dasd_block *block) max = block->base->discipline->max_blocks << block->s2b_shift; } queue_flag_set_unlocked(QUEUE_FLAG_NONROT, block->request_queue); + block->request_queue->limits.max_dev_sectors = max; blk_queue_logical_block_size(block->request_queue, block->bp_block); blk_queue_max_hw_sectors(block->request_queue, max); -- 2.20.1