From b81e8ff503145706aea31d0f0dca8576abaa0fef Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 27 Jun 2024 14:49:11 +0200 Subject: [PATCH] loop: don't set QUEUE_FLAG_NOMERGES BugLink: https://bugs.launchpad.net/bugs/2089884 [ Upstream commit 667ea36378cf7f669044b27871c496e1559c872a ] QUEUE_FLAG_NOMERGES isn't really a driver interface, but a user tunable. There also isn't any good reason to set it in the loop driver. The original commit adding it (5b5e20f421c0b6d "block: loop: set QUEUE_FLAG_NOMERGES for request queue of loop") claims that "It doesn't make sense to enable merge because the I/O submitted to backing file is handled page by page." which of course isn't true for multi-page bvec now, and it never has been for direct I/O, for which commit 40326d8a33d ("block/loop: allow request merge for directio mode") alredy disabled the nomerges flag. Signed-off-by: Christoph Hellwig Reviewed-by: Bart Van Assche Link: https://lore.kernel.org/r/20240627124926.512662-2-hch@lst.de Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin Signed-off-by: Koichiro Den Signed-off-by: Roxana Nicolescu --- drivers/block/loop.c | 15 ++------------- 1 file changed, 2 insertions(+), 13 deletions(-) diff --git a/drivers/block/loop.c b/drivers/block/loop.c index f8145499da38..71d75037410a 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -211,13 +211,10 @@ static void __loop_update_dio(struct loop_device *lo, bool dio) if (lo->lo_state == Lo_bound) blk_mq_freeze_queue(lo->lo_queue); lo->use_dio = use_dio; - if (use_dio) { - blk_queue_flag_clear(QUEUE_FLAG_NOMERGES, lo->lo_queue); + if (use_dio) lo->lo_flags |= LO_FLAGS_DIRECT_IO; - } else { - blk_queue_flag_set(QUEUE_FLAG_NOMERGES, lo->lo_queue); + else lo->lo_flags &= ~LO_FLAGS_DIRECT_IO; - } if (lo->lo_state == Lo_bound) blk_mq_unfreeze_queue(lo->lo_queue); } @@ -2035,14 +2032,6 @@ static int loop_add(int i) /* random number picked from the history block max_sectors cap */ blk_queue_max_hw_sectors(lo->lo_queue, 2560u); - /* - * By default, we do buffer IO, so it doesn't make sense to enable - * merge because the I/O submitted to backing file is handled page by - * page. For directio mode, merge does help to dispatch bigger request - * to underlayer disk. We will enable merge once directio is enabled. - */ - blk_queue_flag_set(QUEUE_FLAG_NOMERGES, lo->lo_queue); - /* * Disable partition scanning by default. The in-kernel partition * scanning can be requested individually per-device during its