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Commit 3b046a97 authored by Robert LeBlanc's avatar Robert LeBlanc Committed by Shaohua Li
Browse files

md/raid1: Refactor raid1_make_request 



Refactor raid1_make_request to make read and write code in their own
functions to clean up the code.

Signed-off-by: default avatarRobert LeBlanc <robert@leblancnet.us>
Signed-off-by: default avatarShaohua Li <shli@fb.com>
parent 0c744ea4

drivers/md/raid1.c

+139 −128
Original line number Diff line number Diff line
@@ -1066,95 +1066,21 @@ static void raid1_unplug(struct blk_plug_cb *cb, bool from_schedule) 
	kfree(plug);

}



static void raid1_make_request(struct mddev *mddev, struct bio * bio)

static void raid1_read_request(struct mddev *mddev, struct bio *bio,

				 struct r1bio *r1_bio)

{

	struct r1conf *conf = mddev->private;

	struct raid1_info *mirror;

	struct r1bio *r1_bio;

	struct bio *read_bio;

	int i, disks;

	struct bitmap *bitmap;

	unsigned long flags;

	struct bitmap *bitmap = mddev->bitmap;

	const int op = bio_op(bio);

	const int rw = bio_data_dir(bio);

	const unsigned long do_sync = (bio->bi_opf & REQ_SYNC);

	const unsigned long do_flush_fua = (bio->bi_opf &

						(REQ_PREFLUSH | REQ_FUA));

	struct md_rdev *blocked_rdev;

	struct blk_plug_cb *cb;

	struct raid1_plug_cb *plug = NULL;

	int first_clone;

	int sectors_handled;

	int max_sectors;

	sector_t start_next_window;



	/*

	 * Register the new request and wait if the reconstruction

	 * thread has put up a bar for new requests.

	 * Continue immediately if no resync is active currently.

	 */



	md_write_start(mddev, bio); /* wait on superblock update early */



	if (bio_data_dir(bio) == WRITE &&

	    ((bio_end_sector(bio) > mddev->suspend_lo &&

	    bio->bi_iter.bi_sector < mddev->suspend_hi) ||

	    (mddev_is_clustered(mddev) &&

	     md_cluster_ops->area_resyncing(mddev, WRITE,

		     bio->bi_iter.bi_sector, bio_end_sector(bio))))) {

		/* As the suspend_* range is controlled by

		 * userspace, we want an interruptible

		 * wait.

		 */

		DEFINE_WAIT(w);

		for (;;) {

			flush_signals(current);

			prepare_to_wait(&conf->wait_barrier,

					&w, TASK_INTERRUPTIBLE);

			if (bio_end_sector(bio) <= mddev->suspend_lo ||

			    bio->bi_iter.bi_sector >= mddev->suspend_hi ||

			    (mddev_is_clustered(mddev) &&

			     !md_cluster_ops->area_resyncing(mddev, WRITE,

				     bio->bi_iter.bi_sector, bio_end_sector(bio))))

				break;

			schedule();

		}

		finish_wait(&conf->wait_barrier, &w);

	}



	start_next_window = wait_barrier(conf, bio);



	bitmap = mddev->bitmap;



	/*

	 * make_request() can abort the operation when read-ahead is being

	 * used and no empty request is available.

	 *

	 */

	r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);



	r1_bio->master_bio = bio;

	r1_bio->sectors = bio_sectors(bio);

	r1_bio->state = 0;

	r1_bio->mddev = mddev;

	r1_bio->sector = bio->bi_iter.bi_sector;



	/* We might need to issue multiple reads to different

	 * devices if there are bad blocks around, so we keep

	 * track of the number of reads in bio->bi_phys_segments.

	 * If this is 0, there is only one r1_bio and no locking

	 * will be needed when requests complete.  If it is

	 * non-zero, then it is the number of not-completed requests.

	 */

	bio->bi_phys_segments = 0;

	bio_clear_flag(bio, BIO_SEG_VALID);



	if (rw == READ) {

		/*

		 * read balancing logic:

		 */

	int rdisk;



	wait_barrier(conf, bio);



read_again:

	rdisk = read_balance(conf, r1_bio, &max_sectors);
@@ -1167,9 +1093,9 @@ static void raid1_make_request(struct mddev *mddev, struct bio * bio) 


	if (test_bit(WriteMostly, &mirror->rdev->flags) &&

	    bitmap) {

			/* Reading from a write-mostly device must

			 * take care not to over-take any writes

			 * that are 'behind'

		/*

		 * Reading from a write-mostly device must take care not to

		 * over-take any writes that are 'behind'

		 */

		raid1_log(mddev, "wait behind writes");

		wait_event(bitmap->behind_wait,
@@ -1200,10 +1126,10 @@ static void raid1_make_request(struct mddev *mddev, struct bio * bio) 
	                              r1_bio->sector);



	if (max_sectors < r1_bio->sectors) {

			/* could not read all from this device, so we will

			 * need another r1_bio.

		/*

		 * could not read all from this device, so we will need another

		 * r1_bio.

		 */



		sectors_handled = (r1_bio->sector + max_sectors

				   - bio->bi_iter.bi_sector);

		r1_bio->sectors = max_sectors;
@@ -1213,10 +1139,11 @@ static void raid1_make_request(struct mddev *mddev, struct bio * bio) 
		else

			bio->bi_phys_segments++;

		spin_unlock_irq(&conf->device_lock);

			/* Cannot call generic_make_request directly

			 * as that will be queued in __make_request

			 * and subsequent mempool_alloc might block waiting

			 * for it.  So hand bio over to raid1d.



		/*

		 * Cannot call generic_make_request directly as that will be

		 * queued in __make_request and subsequent mempool_alloc might

		 * block waiting for it.  So hand bio over to raid1d.

		 */

		reschedule_retry(r1_bio);
@@ -1226,17 +1153,67 @@ static void raid1_make_request(struct mddev *mddev, struct bio * bio) 
		r1_bio->sectors = bio_sectors(bio) - sectors_handled;

		r1_bio->state = 0;

		r1_bio->mddev = mddev;

			r1_bio->sector = bio->bi_iter.bi_sector +

				sectors_handled;

		r1_bio->sector = bio->bi_iter.bi_sector + sectors_handled;

		goto read_again;

	} else

		generic_make_request(read_bio);

		return;

}



static void raid1_write_request(struct mddev *mddev, struct bio *bio,

				struct r1bio *r1_bio)

{

	struct r1conf *conf = mddev->private;

	int i, disks;

	struct bitmap *bitmap = mddev->bitmap;

	unsigned long flags;

	const int op = bio_op(bio);

	const unsigned long do_sync = (bio->bi_opf & REQ_SYNC);

	const unsigned long do_flush_fua = (bio->bi_opf &

						(REQ_PREFLUSH | REQ_FUA));

	struct md_rdev *blocked_rdev;

	struct blk_plug_cb *cb;

	struct raid1_plug_cb *plug = NULL;

	int first_clone;

	int sectors_handled;

	int max_sectors;

	sector_t start_next_window;



	/*

	 * Register the new request and wait if the reconstruction

	 * thread has put up a bar for new requests.

	 * Continue immediately if no resync is active currently.

	 */



	md_write_start(mddev, bio); /* wait on superblock update early */



	if ((bio_end_sector(bio) > mddev->suspend_lo &&

	    bio->bi_iter.bi_sector < mddev->suspend_hi) ||

	    (mddev_is_clustered(mddev) &&

	     md_cluster_ops->area_resyncing(mddev, WRITE,

		     bio->bi_iter.bi_sector, bio_end_sector(bio)))) {



		/*

	 * WRITE:

		 * As the suspend_* range is controlled by userspace, we want

		 * an interruptible wait.

		 */

		DEFINE_WAIT(w);

		for (;;) {

			flush_signals(current);

			prepare_to_wait(&conf->wait_barrier,

					&w, TASK_INTERRUPTIBLE);

			if (bio_end_sector(bio) <= mddev->suspend_lo ||

			    bio->bi_iter.bi_sector >= mddev->suspend_hi ||

			    (mddev_is_clustered(mddev) &&

			     !md_cluster_ops->area_resyncing(mddev, WRITE,

				     bio->bi_iter.bi_sector,

				     bio_end_sector(bio))))

				break;

			schedule();

		}

		finish_wait(&conf->wait_barrier, &w);

	}

	start_next_window = wait_barrier(conf, bio);



	if (conf->pending_count >= max_queued_requests) {

		md_wakeup_thread(mddev->thread);

		raid1_log(mddev, "wait queued");
@@ -1280,8 +1257,7 @@ static void raid1_make_request(struct mddev *mddev, struct bio * bio) 
			int bad_sectors;

			int is_bad;



			is_bad = is_badblock(rdev, r1_bio->sector,

					     max_sectors,

			is_bad = is_badblock(rdev, r1_bio->sector, max_sectors,

					     &first_bad, &bad_sectors);

			if (is_bad < 0) {

				/* mustn't write here until the bad block is
@@ -1370,7 +1346,8 @@ static void raid1_make_request(struct mddev *mddev, struct bio * bio) 
			continue;



		mbio = bio_clone_mddev(bio, GFP_NOIO, mddev);

		bio_trim(mbio, r1_bio->sector - bio->bi_iter.bi_sector, max_sectors);

		bio_trim(mbio, r1_bio->sector - bio->bi_iter.bi_sector,

			 max_sectors);



		if (first_clone) {

			/* do behind I/O ?
@@ -1464,6 +1441,40 @@ static void raid1_make_request(struct mddev *mddev, struct bio * bio) 
	wake_up(&conf->wait_barrier);

}



static void raid1_make_request(struct mddev *mddev, struct bio *bio)

{

	struct r1conf *conf = mddev->private;

	struct r1bio *r1_bio;



	/*

	 * make_request() can abort the operation when read-ahead is being

	 * used and no empty request is available.

	 *

	 */

	r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);



	r1_bio->master_bio = bio;

	r1_bio->sectors = bio_sectors(bio);

	r1_bio->state = 0;

	r1_bio->mddev = mddev;

	r1_bio->sector = bio->bi_iter.bi_sector;



	/*

	 * We might need to issue multiple reads to different devices if there

	 * are bad blocks around, so we keep track of the number of reads in

	 * bio->bi_phys_segments.  If this is 0, there is only one r1_bio and

	 * no locking will be needed when requests complete.  If it is

	 * non-zero, then it is the number of not-completed requests.

	 */

	bio->bi_phys_segments = 0;

	bio_clear_flag(bio, BIO_SEG_VALID);



	if (bio_data_dir(bio) == READ)

		raid1_read_request(mddev, bio, r1_bio);

	else

		raid1_write_request(mddev, bio, r1_bio);

}



static void raid1_status(struct seq_file *seq, struct mddev *mddev)

{

	struct r1conf *conf = mddev->private;