Commit b7f8dff0 authored by Mike Snitzer's avatar Mike Snitzer
Browse files

dm: simplify dm_sumbit_bio_remap interface 



Remove the from_wq argument from dm_sumbit_bio_remap(). Eliminates the
need for dm_sumbit_bio_remap() callers to know whether they are
calling for a workqueue or from the original dm_submit_bio().

Add map_task to dm_io struct, record the map_task in alloc_io and
clear it after all target ->map() calls have completed. Update
dm_sumbit_bio_remap to check if 'current' matches io->map_task rather
than rely on passed 'from_rq' argument.

This change really simplifies the chore of porting each DM target to
using dm_sumbit_bio_remap() because there is no longer the risk of
programming error by not completely knowing all the different contexts
a particular method that calls dm_sumbit_bio_remap() might be used in.

Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent a9251281

drivers/md/dm-core.h

+1 −0
Original line number Diff line number Diff line
@@ -237,6 +237,7 @@ struct dm_io { 
	unsigned long start_time;

	void *data;

	struct hlist_node node;

	struct task_struct *map_task;

	spinlock_t endio_lock;

	struct dm_stats_aux stats_aux;

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

drivers/md/dm-crypt.c

+3 −3
Original line number Diff line number Diff line
@@ -1857,7 +1857,7 @@ static int kcryptd_io_read(struct dm_crypt_io *io, gfp_t gfp) 
		return 1;

	}



	dm_submit_bio_remap(io->base_bio, clone, (gfp != CRYPT_MAP_READ_GFP));

	dm_submit_bio_remap(io->base_bio, clone);

	return 0;

}
@@ -1883,7 +1883,7 @@ static void kcryptd_io_write(struct dm_crypt_io *io) 
{

	struct bio *clone = io->ctx.bio_out;



	dm_submit_bio_remap(io->base_bio, clone, true);

	dm_submit_bio_remap(io->base_bio, clone);

}



#define crypt_io_from_node(node) rb_entry((node), struct dm_crypt_io, rb_node)
@@ -1962,7 +1962,7 @@ static void kcryptd_crypt_write_io_submit(struct dm_crypt_io *io, int async) 


	if ((likely(!async) && test_bit(DM_CRYPT_NO_OFFLOAD, &cc->flags)) ||

	    test_bit(DM_CRYPT_NO_WRITE_WORKQUEUE, &cc->flags)) {

		dm_submit_bio_remap(io->base_bio, clone, true);

		dm_submit_bio_remap(io->base_bio, clone);

		return;

	}

drivers/md/dm-delay.c

+1 −1
Original line number Diff line number Diff line
@@ -72,7 +72,7 @@ static void flush_bios(struct bio *bio) 
	while (bio) {

		n = bio->bi_next;

		bio->bi_next = NULL;

		dm_submit_bio_remap(bio, NULL, true);

		dm_submit_bio_remap(bio, NULL);

		bio = n;

	}

}

drivers/md/dm-thin.c

+2 −2
Original line number Diff line number Diff line
@@ -755,7 +755,7 @@ static void issue(struct thin_c *tc, struct bio *bio) 
	struct pool *pool = tc->pool;



	if (!bio_triggers_commit(tc, bio)) {

		dm_submit_bio_remap(bio, NULL, true);

		dm_submit_bio_remap(bio, NULL);

		return;

	}
@@ -2383,7 +2383,7 @@ static void process_deferred_bios(struct pool *pool) 
		if (bio->bi_opf & REQ_PREFLUSH)

			bio_endio(bio);

		else

			dm_submit_bio_remap(bio, NULL, true);

			dm_submit_bio_remap(bio, NULL);

	}

}

drivers/md/dm.c

+4 −4
Original line number Diff line number Diff line
@@ -574,6 +574,7 @@ static struct dm_io *alloc_io(struct mapped_device *md, struct bio *bio) 
	this_cpu_inc(*md->pending_io);

	io->orig_bio = NULL;

	io->md = md;

	io->map_task = current;

	spin_lock_init(&io->endio_lock);



	io->start_time = jiffies;
@@ -1189,15 +1190,13 @@ static inline void __dm_submit_bio_remap(struct bio *clone, 
/*

 * @clone: clone bio that DM core passed to target's .map function

 * @tgt_clone: clone of @clone bio that target needs submitted

 * @from_wq: caller is a workqueue thread managed by DM target

 *

 * Targets should use this interface to submit bios they take

 * ownership of when returning DM_MAPIO_SUBMITTED.

 *

 * Target should also enable ti->accounts_remapped_io

 */

void dm_submit_bio_remap(struct bio *clone, struct bio *tgt_clone,

			 bool from_wq)

void dm_submit_bio_remap(struct bio *clone, struct bio *tgt_clone)

{

	struct dm_target_io *tio = clone_to_tio(clone);

	struct dm_io *io = tio->io;
@@ -1212,7 +1211,7 @@ void dm_submit_bio_remap(struct bio *clone, struct bio *tgt_clone, 
	 * Account io->origin_bio to DM dev on behalf of target

	 * that took ownership of IO with DM_MAPIO_SUBMITTED.

	 */

	if (!from_wq) {

	if (io->map_task == current) {

		/* Still in target's map function */

		io->start_io_acct = true;

	} else {
@@ -1568,6 +1567,7 @@ static void dm_split_and_process_bio(struct mapped_device *md, 
	}



	error = __split_and_process_bio(&ci);

	ci.io->map_task = NULL;

	if (error || !ci.sector_count)

		goto out;