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loop: don't set QUEUE_FLAG_NOMERGES

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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 (5b5e20f421 "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 40326d8a33
("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>
This commit is contained in:
Christoph Hellwig
2024-06-27 14:49:11 +02:00
committed by Jens Axboe
parent 0676c434a9
commit 667ea36378
1 changed files with 2 additions and 13 deletions
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15
drivers/block/loop.c
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@@ -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);
}
@@ -2030,14 +2027,6 @@ 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