md: Remove extra mddev_get() in md_seq_start()

A regression is seen where mddev devices stay permanently after they
are stopped due to an elevated reference count.

This was tracked down to an extra mddev_get() in md_seq_start().

It only happened rarely because most of the time the md_seq_start()
is called with a zero offset. The path with an extra mddev_get() only
happens when it starts with a non-zero offset.

The commit noted below changed an mddev_get() to check its success
but inadvertently left the original call in. Remove the extra call.

Fixes: 12a6caf27324 ("md: only delete entries from all_mddevs when the disk is freed")
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Guoqing Jiang <Guoqing.jiang@linux.dev>
Signed-off-by: Song Liu <song@kernel.org>

diff --git a/drivers/md/md.c b/drivers/md/md.c
index afaf36b..9dc0175 100644 (file)
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -8154,7 +8154,6 @@ static void *md_seq_start(struct seq_file *seq, loff_t *pos)
        list_for_each(tmp,&all_mddevs)
                if (!l--) {
                        mddev = list_entry(tmp, struct mddev, all_mddevs);
-                       mddev_get(mddev);
                        if (!mddev_get(mddev))
                                continue;
                        spin_unlock(&all_mddevs_lock);