linux-kernel - [PATCH 06/13] nvdimm/blk: avoid calling del

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Date:   Fri, 15 Oct 2021 16:52:12 -0700
From:   Luis Chamberlain <mcgrof@...nel.org>
To:     axboe@...nel.dk, geoff@...radead.org, mpe@...erman.id.au,
        benh@...nel.crashing.org, paulus@...ba.org, jim@...n.com,
        minchan@...nel.org, ngupta@...are.org, senozhatsky@...omium.org,
        richard@....at, miquel.raynal@...tlin.com, vigneshr@...com,
        dan.j.williams@...el.com, vishal.l.verma@...el.com,
        dave.jiang@...el.com, ira.weiny@...el.com, kbusch@...nel.org,
        hch@....de, sagi@...mberg.me
Cc:     linux-block@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
        linux-mtd@...ts.infradead.org, nvdimm@...ts.linux.dev,
        linux-nvme@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Luis Chamberlain <mcgrof@...nel.org>
Subject: [PATCH 06/13] nvdimm/blk: avoid calling del_gendisk() on early failures

If nd_integrity_init() fails we'd get del_gendisk() called,
but that's not correct as we should only call that if we're
done with device_add_disk(). Fix this by providing unwinding
prior to the devm call being registered and moving the devm
registration to the very end.

This should fix calling del_gendisk() if nd_integrity_init()
fails. I only spotted this issue through code inspection. It
does not fix any real world bug.

Signed-off-by: Luis Chamberlain <mcgrof@...nel.org>
---
 drivers/nvdimm/blk.c | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/drivers/nvdimm/blk.c b/drivers/nvdimm/blk.c
index 088d3dd6f6fa..591fa1f86f1e 100644
--- a/drivers/nvdimm/blk.c
+++ b/drivers/nvdimm/blk.c
@@ -240,6 +240,7 @@ static int nsblk_attach_disk(struct nd_namespace_blk *nsblk)
 	resource_size_t available_disk_size;
 	struct gendisk *disk;
 	u64 internal_nlba;
+	int rc;
 
 	internal_nlba = div_u64(nsblk->size, nsblk_internal_lbasize(nsblk));
 	available_disk_size = internal_nlba * nsblk_sector_size(nsblk);
@@ -256,20 +257,26 @@ static int nsblk_attach_disk(struct nd_namespace_blk *nsblk)
 	blk_queue_logical_block_size(disk->queue, nsblk_sector_size(nsblk));
 	blk_queue_flag_set(QUEUE_FLAG_NONROT, disk->queue);
 
-	if (devm_add_action_or_reset(dev, nd_blk_release_disk, disk))
-		return -ENOMEM;
-
 	if (nsblk_meta_size(nsblk)) {
-		int rc = nd_integrity_init(disk, nsblk_meta_size(nsblk));
+		rc = nd_integrity_init(disk, nsblk_meta_size(nsblk));
 
 		if (rc)
-			return rc;
+			goto out_before_devm_err;
 	}
 
 	set_capacity(disk, available_disk_size >> SECTOR_SHIFT);
 	device_add_disk(dev, disk, NULL);
+
+	/* nd_blk_release_disk() is called if this fails */
+	if (devm_add_action_or_reset(dev, nd_blk_release_disk, disk))
+		return -ENOMEM;
+
 	nvdimm_check_and_set_ro(disk);
 	return 0;
+
+out_before_devm_err:
+	blk_cleanup_disk(disk);
+	return rc;
 }
 
 static int nd_blk_probe(struct device *dev)
-- 
2.30.2