From 05ce7fb946c37fc6fc8bf14073279e570f78f69e Mon Sep 17 00:00:00 2001
From: Chris Webb <chris@arachsys.com>
Date: Wed, 1 Jun 2022 12:03:07 +0100
Subject: [PATCH] md: Explicitly create command-line configured devices
Git-commit: 05ce7fb946c37fc6fc8bf14073279e570f78f69e
Patch-mainline: v6.0-rc1
References: jsc#PED-2766

Boot-time assembly of arrays with md= command-line arguments breaks when
CONFIG_BLOCK_LEGACY_AUTOLOAD is unset. md_setup_drive() in md-autodetect.c
calls blkdev_get_by_dev(), assuming this implicitly creates the block
device.

Fix this by attempting to md_alloc() the array first. As in the probe path,
ignore any error as failure is caught by blkdev_get_by_dev() anyway.

Signed-off-by: Chris Webb <chris@arachsys.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Coly Li <colyli@suse.de>

---
 drivers/md/md-autodetect.c | 1 +
 drivers/md/md.c            | 2 +-
 drivers/md/md.h            | 1 +
 3 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/md/md-autodetect.c b/drivers/md/md-autodetect.c
index 2cf973722f59..344910ba435c 100644
--- a/drivers/md/md-autodetect.c
+++ b/drivers/md/md-autodetect.c
@@ -169,6 +169,7 @@ static void __init md_setup_drive(struct md_setup_args *args)
 
 	pr_info("md: Loading %s: %s\n", name, args->device_names);
 
+	md_alloc(mdev, name);
 	bdev = blkdev_get_by_dev(mdev, FMODE_READ, NULL);
 	if (IS_ERR(bdev)) {
 		pr_err("md: open failed - cannot start array %s\n", name);
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 621cf85962da..f511f183aca6 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -5623,7 +5623,7 @@ int mddev_init_writes_pending(struct mddev *mddev)
 }
 EXPORT_SYMBOL_GPL(mddev_init_writes_pending);
 
-static int md_alloc(dev_t dev, char *name)
+int md_alloc(dev_t dev, char *name)
 {
 	/*
 	 * If dev is zero, name is the name of a device to allocate with
diff --git a/drivers/md/md.h b/drivers/md/md.h
index 551c0a349cb5..861088b3d236 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -765,6 +765,7 @@ extern int md_integrity_add_rdev(struct md_rdev *rdev, struct mddev *mddev);
 extern int strict_strtoul_scaled(const char *cp, unsigned long *res, int scale);
 
 extern void mddev_init(struct mddev *mddev);
+int md_alloc(dev_t dev, char *name);
 extern int md_run(struct mddev *mddev);
 extern int md_start(struct mddev *mddev);
 extern void md_stop(struct mddev *mddev);
-- 
2.35.3