6.10-stable review patch. If anyone has any objections, please let me know.
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From: Christoph Hellwig hch@lst.de
[ 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 hch@lst.de Reviewed-by: Bart Van Assche bvanassche@acm.org Link: https://lore.kernel.org/r/20240627124926.512662-2-hch@lst.de Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org --- 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 1153721bc7c25..41cfcf9efcfc5 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); } @@ -2059,14 +2056,6 @@ static int loop_add(int i) } lo->lo_queue = lo->lo_disk->queue;
- /* - * 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