Date:   Fri, 3 Dec 2021 07:57:26 +0100
From:   Christoph Hellwig <hch@lst.de>
To:     Geert Uytterhoeven <geert+renesas@glider.be>
Cc:     Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
        Miquel Raynal <miquel.raynal@bootlin.com>,
        Richard Weinberger <richard@nod.at>,
        Vignesh Raghavendra <vigneshr@ti.com>,
        Tudor Ambarus <tudor.ambarus@microchip.com>,
        Michael Walle <michael@walle.cc>,
        Pratyush Yadav <p.yadav@ti.com>, linux-mtd@lists.infradead.org,
        linux-block@vger.kernel.org, linux-renesas-soc@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH/RFC -nxt] mtd_blkdevs: Set GENHD_FL_NO_PART
Message-ID: <20211203065726.GA3072@lst.de>
References: <c26dfdf9ce56e92d23530a09db386b283e62845d.1638289204.git.geert+renesas@glider.be>
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User-Agent: Mutt/1.5.17 (2007-11-01)
Precedence: bulk

I think we need the patch below to restore the old behavior where a
partitions scan happens only for those sub-drivers that do report a
partition shift.

MTD maintainers: is this intentional that raw mtdblock does not support
partitions, but the various "FTL" modules do?

diff --git a/drivers/mtd/mtd_blkdevs.c b/drivers/mtd/mtd_blkdevs.c
index 113f86df76038..57a22d2ebaeca 100644
--- a/drivers/mtd/mtd_blkdevs.c
+++ b/drivers/mtd/mtd_blkdevs.c
@@ -345,6 +345,8 @@ int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
 	gd->first_minor = (new->devnum) << tr->part_bits;
 	gd->minors = 1 << tr->part_bits;
 	gd->fops = &mtd_block_ops;
+	if (!tr->part_bits)
+		gd->flags |= GENHD_FL_NO_PART;
 
 	if (tr->part_bits)
 		if (new->devnum < 26)