mtd: core: don't remove debugfs directory if device is in use

[ Upstream commit c13de2386c78e890d4ae6f01a85eefd0b293fb08 ]

Previously, if del_mtd_device() failed with -EBUSY due to a non-zero
usecount, a subsequent call to attempt the deletion again would try to
remove a debugfs directory that had already been removed and panic.
With this change the second call can instead proceed safely.

Fixes: e8e3edb95ce6 ("mtd: create per-device and module-scope debugfs entries")
Signed-off-by: Zev Weiss <zev@bewilderbeest.net>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20211014203953.5424-1-zev@bewilderbeest.net
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index c8fd7f7..1532291 100644 (file)
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -724,8 +724,6 @@ int del_mtd_device(struct mtd_info *mtd)
 
        mutex_lock(&mtd_table_mutex);
 
-       debugfs_remove_recursive(mtd->dbg.dfs_dir);
-
        if (idr_find(&mtd_idr, mtd->index) != mtd) {
                ret = -ENODEV;
                goto out_error;
@@ -741,6 +739,8 @@ int del_mtd_device(struct mtd_info *mtd)
                       mtd->index, mtd->name, mtd->usecount);
                ret = -EBUSY;
        } else {
+               debugfs_remove_recursive(mtd->dbg.dfs_dir);
+
                /* Try to remove the NVMEM provider */
                if (mtd->nvmem)
                        nvmem_unregister(mtd->nvmem);