[PATCH v2] mmc: block: fix RPMB device unregister ordering

[Ao Sun <ao.sun@transsion.com>]

From: Ao Sun <ao.sun@transsion.com>

Since commit 7852028a35f0 ("mmc: block: register RPMB partition with
the RPMB subsystem"), each mmc RPMB partition is represented by two
device objects:
 - the mmc-owned device (`rpmb->dev`, backing the legacy /dev/mmcblkXrpmb
   char device) and
 - the rpmb-core device (`rdev`, backing /dev/rpmbN).

The child RPMB device holds a reference to its parent, so the 
parent's release callback cannot be invoked if the child device 
is still registered.

Remove rpmb_dev_unregister() from the parent release handler and 
unregister the child RPMB device in the remove path before tearing 
down the parent device.

Also delete the extra blank line between mmc_blk_remove_rpmb_part() 
and {.

Fixes: 7852028a35f0 ("mmc: block: register RPMB partition with the RPMB subsystem")
Cc: stable@vger.kernel.org
Signed-off-by: Jiazi Li <jiazi.li@transsion.com>
Signed-off-by: Ao Sun <ao.sun@transsion.com>
Reviewed-by: Avri Altman <avri.altman@sandisk.com>
---
Changes in v2:
  - add background describing the two RPMB device objects
  - add Fixes and Cc
  - collect Reviewed-by
---
 drivers/mmc/core/block.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
index 0274e8d07660..54a923ba4f1e 100644
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -2715,7 +2715,6 @@ static void mmc_blk_rpmb_device_release(struct device *dev)
 {
 	struct mmc_rpmb_data *rpmb = dev_get_drvdata(dev);
 
-	rpmb_dev_unregister(rpmb->rdev);
 	mmc_blk_put(rpmb->md);
 	ida_free(&mmc_rpmb_ida, rpmb->id);
 	kfree(rpmb);
@@ -2930,8 +2929,8 @@ static int mmc_blk_alloc_rpmb_part(struct mmc_card *card,
 }
 
 static void mmc_blk_remove_rpmb_part(struct mmc_rpmb_data *rpmb)
-
 {
+	rpmb_dev_unregister(rpmb->rdev);
 	cdev_device_del(&rpmb->chrdev, &rpmb->dev);
 	put_device(&rpmb->dev);
 }
-- 
2.34.1