From: Hannes Reinecke <hare@suse.de>
Date: Tue, 19 May 2020 10:14:23 +0200
Subject: [PATCH] dm zoned: terminate reclaim on congestion
Git-commit: a16b7dee302d2040d9e1fedff2161d1aceda0e8c
Patch-mainline: v5.8-rc1
References: bsc#1175995,jsc#SLE-15608

When dmz_get_chunk_mapping() selects a zone which is under reclaim
we should terminate the reclaim copy process. Since we're changing
the zone itself, reclaim needs to run afterwards again anyway.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Hannes Reinecke <hare@suse.com>
---
 drivers/md/dm-zoned-metadata.c | 2 ++
 drivers/md/dm-zoned-reclaim.c  | 6 ++++--
 drivers/md/dm-zoned.h          | 3 +++
 3 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/md/dm-zoned-metadata.c b/drivers/md/dm-zoned-metadata.c
index b5fd67eff046..db0dc2b5d44d 100644
--- a/drivers/md/dm-zoned-metadata.c
+++ b/drivers/md/dm-zoned-metadata.c
@@ -1851,7 +1851,9 @@ static void dmz_wait_for_reclaim(struct dmz_metadata *zmd, struct dm_zone *zone)
 {
 	dmz_unlock_map(zmd);
 	dmz_unlock_metadata(zmd);
+	set_bit(DMZ_RECLAIM_TERMINATE, &zone->flags);
 	wait_on_bit_timeout(&zone->flags, DMZ_RECLAIM, TASK_UNINTERRUPTIBLE, HZ);
+	clear_bit(DMZ_RECLAIM_TERMINATE, &zone->flags);
 	dmz_lock_metadata(zmd);
 	dmz_lock_map(zmd);
 }
diff --git a/drivers/md/dm-zoned-reclaim.c b/drivers/md/dm-zoned-reclaim.c
index d62f6890b92c..571bc1d41bab 100644
--- a/drivers/md/dm-zoned-reclaim.c
+++ b/drivers/md/dm-zoned-reclaim.c
@@ -143,6 +143,9 @@ static int dmz_reclaim_copy(struct dmz_reclaim *zrc,
 		if (dst_dev->flags & DMZ_BDEV_DYING)
 			return -EIO;
 
+		if (dmz_reclaim_should_terminate(src_zone))
+			return -EINTR;
+
 		/* Get a valid region from the source zone */
 		ret = dmz_first_valid_block(zmd, src_zone, &block);
 		if (ret <= 0)
@@ -515,7 +518,7 @@ static void dmz_reclaim_work(struct work_struct *work)
 		dmz_nr_rnd_zones(zmd));
 
 	ret = dmz_do_reclaim(zrc);
-	if (ret) {
+	if (ret && ret != -EINTR) {
 		DMDEBUG("(%s): Reclaim error %d",
 			dmz_metadata_label(zmd), ret);
 		if (!dmz_check_dev(zmd))
@@ -615,4 +618,3 @@ void dmz_schedule_reclaim(struct dmz_reclaim *zrc)
 	if (dmz_should_reclaim(zrc, p_unmap))
 		mod_delayed_work(zrc->wq, &zrc->work, 0);
 }
-
diff --git a/drivers/md/dm-zoned.h b/drivers/md/dm-zoned.h
index 288054dd7cf4..8083607b9535 100644
--- a/drivers/md/dm-zoned.h
+++ b/drivers/md/dm-zoned.h
@@ -127,6 +127,7 @@ enum {
 	/* Zone internal state */
 	DMZ_RECLAIM,
 	DMZ_SEQ_WRITE_ERR,
+	DMZ_RECLAIM_TERMINATE,
 };
 
 /*
@@ -140,6 +141,8 @@ enum {
 #define dmz_is_readonly(z)	test_bit(DMZ_READ_ONLY, &(z)->flags)
 #define dmz_in_reclaim(z)	test_bit(DMZ_RECLAIM, &(z)->flags)
 #define dmz_seq_write_err(z)	test_bit(DMZ_SEQ_WRITE_ERR, &(z)->flags)
+#define dmz_reclaim_should_terminate(z) \
+				test_bit(DMZ_RECLAIM_TERMINATE, &(z)->flags)
 
 #define dmz_is_meta(z)		test_bit(DMZ_META, &(z)->flags)
 #define dmz_is_buf(z)		test_bit(DMZ_BUF, &(z)->flags)
-- 
2.16.4