Commit 1cdb5b41 authored by Logan Gunthorpe's avatar Logan Gunthorpe Committed by Jens Axboe
Browse files

md/raid5: Drop the do_prepare flag in raid5_make_request() 



prepare_to_wait() can be reasonably called after schedule instead of
setting a flag and preparing in the next loop iteration.

This means that prepare_to_wait() will be called before
read_seqcount_begin(), but there shouldn't be any reason that the order
matters here. On the first iteration of the loop prepare_to_wait() is
already called first.

Signed-off-by: default avatarLogan Gunthorpe <logang@deltatee.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarGuoqing Jiang <guoqing.jiang@linux.dev>
Signed-off-by: default avatarSong Liu <song@kernel.org>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent f4aec6a0

drivers/md/raid5.c

+2 −6
Original line number Diff line number Diff line
@@ -5919,7 +5919,6 @@ static bool raid5_make_request(struct mddev *mddev, struct bio * bi) 
	const int rw = bio_data_dir(bi);

	enum stripe_result res;

	DEFINE_WAIT(w);

	bool do_prepare;



	if (unlikely(bi->bi_opf & REQ_PREFLUSH)) {

		int ret = log_handle_flush_request(conf, bi);
@@ -5977,12 +5976,8 @@ static bool raid5_make_request(struct mddev *mddev, struct bio * bi) 
	for (; logical_sector < last_sector; logical_sector += RAID5_STRIPE_SECTORS(conf)) {

		int seq;



		do_prepare = false;

	retry:

		seq = read_seqcount_begin(&conf->gen_lock);

		if (do_prepare)

			prepare_to_wait(&conf->wait_for_overlap, &w,

				TASK_UNINTERRUPTIBLE);



		res = make_stripe_request(mddev, conf, &ctx, logical_sector,

					  bi, seq);
@@ -5994,7 +5989,8 @@ static bool raid5_make_request(struct mddev *mddev, struct bio * bi) 


		if (res == STRIPE_SCHEDULE_AND_RETRY) {

			schedule();

			do_prepare = true;

			prepare_to_wait(&conf->wait_for_overlap, &w,

					TASK_UNINTERRUPTIBLE);

			goto retry;

		}

	}