Commit 4d7bca13 authored by Mike Snitzer's avatar Mike Snitzer
Browse files

dm: consolidate spinlocks in dm_io struct 



No reason to have separate startio_lock and endio_lock given endio_lock
could be used during submission anyway.

This change leaves the dm_io struct weighing in at 256 bytes (down
from 272 bytes, so saves a cacheline).

Signed-off-by: default avatarMike Snitzer <snitzer@kernel.org>
parent bd4a6dd2

drivers/md/dm-core.h

+1 −2
Original line number Diff line number Diff line
@@ -250,12 +250,11 @@ struct dm_io { 
	struct mapped_device *md;

	struct bio *orig_bio;

	blk_status_t status;

	spinlock_t lock;

	unsigned long start_time;

	void *data;

	struct hlist_node node;

	struct task_struct *map_task;

	spinlock_t startio_lock;

	spinlock_t endio_lock;

	struct dm_stats_aux stats_aux;

	/* last member of dm_target_io is 'struct bio' */

	struct dm_target_io tio;

drivers/md/dm.c

+5 −6
Original line number Diff line number Diff line
@@ -550,9 +550,9 @@ static void dm_start_io_acct(struct dm_io *io, struct bio *clone) 
		if (dm_io_flagged(io, DM_IO_ACCOUNTED))

			return;

		/* Can afford locking given DM_TIO_IS_DUPLICATE_BIO */

		spin_lock_irqsave(&io->startio_lock, flags);

		spin_lock_irqsave(&io->lock, flags);

		dm_io_set_flag(io, DM_IO_ACCOUNTED);

		spin_unlock_irqrestore(&io->startio_lock, flags);

		spin_unlock_irqrestore(&io->lock, flags);

	}



	__dm_start_io_acct(io, bio);
@@ -584,8 +584,7 @@ static struct dm_io *alloc_io(struct mapped_device *md, struct bio *bio) 
	io->orig_bio = NULL;

	io->md = md;

	io->map_task = current;

	spin_lock_init(&io->startio_lock);

	spin_lock_init(&io->endio_lock);

	spin_lock_init(&io->lock);

	io->start_time = jiffies;

	io->flags = 0;
@@ -933,11 +932,11 @@ void dm_io_dec_pending(struct dm_io *io, blk_status_t error) 
	/* Push-back supersedes any I/O errors */

	if (unlikely(error)) {

		unsigned long flags;

		spin_lock_irqsave(&io->endio_lock, flags);

		spin_lock_irqsave(&io->lock, flags);

		if (!(io->status == BLK_STS_DM_REQUEUE &&

		      __noflush_suspending(io->md)))

			io->status = error;

		spin_unlock_irqrestore(&io->endio_lock, flags);

		spin_unlock_irqrestore(&io->lock, flags);

	}



	if (atomic_dec_and_test(&io->io_count))