Update Linux to v5.4.148

Sourced from [1]

[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.4.148.tar.gz

Change-Id: Ib3d26c5ba9b022e2e03533005c4fed4d7c30b61b
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index dbcc1e4..54ecfea 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -576,10 +576,12 @@
 
 	/* Do we need to select a new pgpath? */
 	pgpath = READ_ONCE(m->current_pgpath);
-	queue_io = test_bit(MPATHF_QUEUE_IO, &m->flags);
-	if (!pgpath || !queue_io)
+	if (!pgpath || !test_bit(MPATHF_QUEUE_IO, &m->flags))
 		pgpath = choose_pgpath(m, bio->bi_iter.bi_size);
 
+	/* MPATHF_QUEUE_IO might have been cleared by choose_pgpath. */
+	queue_io = test_bit(MPATHF_QUEUE_IO, &m->flags);
+
 	if ((pgpath && queue_io) ||
 	    (!pgpath && test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags))) {
 		/* Queue for the daemon to resubmit */
@@ -599,45 +601,10 @@
 	return pgpath;
 }
 
-static struct pgpath *__map_bio_fast(struct multipath *m, struct bio *bio)
-{
-	struct pgpath *pgpath;
-	unsigned long flags;
-
-	/* Do we need to select a new pgpath? */
-	/*
-	 * FIXME: currently only switching path if no path (due to failure, etc)
-	 * - which negates the point of using a path selector
-	 */
-	pgpath = READ_ONCE(m->current_pgpath);
-	if (!pgpath)
-		pgpath = choose_pgpath(m, bio->bi_iter.bi_size);
-
-	if (!pgpath) {
-		if (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) {
-			/* Queue for the daemon to resubmit */
-			spin_lock_irqsave(&m->lock, flags);
-			bio_list_add(&m->queued_bios, bio);
-			spin_unlock_irqrestore(&m->lock, flags);
-			queue_work(kmultipathd, &m->process_queued_bios);
-
-			return ERR_PTR(-EAGAIN);
-		}
-		return NULL;
-	}
-
-	return pgpath;
-}
-
 static int __multipath_map_bio(struct multipath *m, struct bio *bio,
 			       struct dm_mpath_io *mpio)
 {
-	struct pgpath *pgpath;
-
-	if (!m->hw_handler_name)
-		pgpath = __map_bio_fast(m, bio);
-	else
-		pgpath = __map_bio(m, bio);
+	struct pgpath *pgpath = __map_bio(m, bio);
 
 	if (IS_ERR(pgpath))
 		return DM_MAPIO_SUBMITTED;
@@ -1223,17 +1190,25 @@
 static void flush_multipath_work(struct multipath *m)
 {
 	if (m->hw_handler_name) {
-		set_bit(MPATHF_PG_INIT_DISABLED, &m->flags);
-		smp_mb__after_atomic();
+		unsigned long flags;
 
-		if (atomic_read(&m->pg_init_in_progress))
+		if (!atomic_read(&m->pg_init_in_progress))
+			goto skip;
+
+		spin_lock_irqsave(&m->lock, flags);
+		if (atomic_read(&m->pg_init_in_progress) &&
+		    !test_and_set_bit(MPATHF_PG_INIT_DISABLED, &m->flags)) {
+			spin_unlock_irqrestore(&m->lock, flags);
+
 			flush_workqueue(kmpath_handlerd);
-		multipath_wait_for_pg_init_completion(m);
+			multipath_wait_for_pg_init_completion(m);
 
-		clear_bit(MPATHF_PG_INIT_DISABLED, &m->flags);
-		smp_mb__after_atomic();
+			spin_lock_irqsave(&m->lock, flags);
+			clear_bit(MPATHF_PG_INIT_DISABLED, &m->flags);
+		}
+		spin_unlock_irqrestore(&m->lock, flags);
 	}
-
+skip:
 	if (m->queue_mode == DM_TYPE_BIO_BASED)
 		flush_work(&m->process_queued_bios);
 	flush_work(&m->trigger_event);
@@ -1889,7 +1864,7 @@
 	int r;
 
 	current_pgpath = READ_ONCE(m->current_pgpath);
-	if (!current_pgpath)
+	if (!current_pgpath || !test_bit(MPATHF_QUEUE_IO, &m->flags))
 		current_pgpath = choose_pgpath(m, 0);
 
 	if (current_pgpath) {