Commit a862e4e2 authored by Mike Snitzer's avatar Mike Snitzer
Browse files

dm mpath: simplify __must_push_back 



Remove micro-optimization that infers device is between presuspend and
resume (was done purely to avoid call to dm_noflush_suspending, which
isn't expensive anyway).

Remove flags argument since they are no longer checked.

And remove must_push_back_bio() since it was simply a call to
__must_push_back().

Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent 27d49ac1

drivers/md/dm-mpath.c

+5 −23
Original line number Diff line number Diff line
@@ -457,33 +457,15 @@ do { \ 
/*

 * Check whether bios must be queued in the device-mapper core rather

 * than here in the target.

 *

 * If MPATHF_QUEUE_IF_NO_PATH and MPATHF_SAVED_QUEUE_IF_NO_PATH hold

 * the same value then we are not between multipath_presuspend()

 * and multipath_resume() calls and we have no need to check

 * for the DMF_NOFLUSH_SUSPENDING flag.

 */

static bool __must_push_back(struct multipath *m, unsigned long flags)

static bool __must_push_back(struct multipath *m)

{

	return ((test_bit(MPATHF_QUEUE_IF_NO_PATH, &flags) !=

		 test_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &flags)) &&

		dm_noflush_suspending(m->ti));

	return dm_noflush_suspending(m->ti);

}



/*

 * Following functions use READ_ONCE to get atomic access to

 * all m->flags to avoid taking spinlock

 */

static bool must_push_back_rq(struct multipath *m)

{

	unsigned long flags = READ_ONCE(m->flags);

	return test_bit(MPATHF_QUEUE_IF_NO_PATH, &flags) || __must_push_back(m, flags);

}



static bool must_push_back_bio(struct multipath *m)

{

	unsigned long flags = READ_ONCE(m->flags);

	return __must_push_back(m, flags);

	return test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags) || __must_push_back(m);

}



/*
@@ -620,7 +602,7 @@ static int __multipath_map_bio(struct multipath *m, struct bio *bio, 
		return DM_MAPIO_SUBMITTED;



	if (!pgpath) {

		if (must_push_back_bio(m))

		if (__must_push_back(m))

			return DM_MAPIO_REQUEUE;

		dm_report_EIO(m);

		return DM_MAPIO_KILL;
@@ -1642,7 +1624,7 @@ static int multipath_end_io_bio(struct dm_target *ti, struct bio *clone, 


	if (atomic_read(&m->nr_valid_paths) == 0 &&

	    !test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) {

		if (must_push_back_bio(m)) {

		if (__must_push_back(m)) {

			r = DM_ENDIO_REQUEUE;

		} else {

			dm_report_EIO(m);