[PATCH v4 2/2] mmc: sdio: fix possible memory leak in some error path

[Yang Yingliang <yangyingliang@xxxxxxxxxx>]

If sdio_add_func() or sdio_init_func() fails, sdio_remove_func() can
not free the memory, because the sdio function is not presented in
these two cases, it won't call put_device().

To fix these leaks, make sdio_func_present() only control whether
device_del() needs to be called or not. Then, put_device() is called
to give up the reference which was set in device_initialize(), the
memory can be freed in sdio_release_func().

In error case in sdio_init_func(), the reference of 'card->dev' is
not get, so set 'func->card' to NULL to avoid redundant put in
sdio_free_func_cis().

Fixes: 3d10a1ba0d37 ("sdio: fix reference counting in sdio_remove_func()")
Signed-off-by: Yang Yingliang <yangyingliang@xxxxxxxxxx>
---
 drivers/mmc/core/sdio.c     | 1 +
 drivers/mmc/core/sdio_bus.c | 8 ++++----
 drivers/mmc/core/sdio_cis.c | 3 ++-
 3 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c
index f64b9ac76a5c..ff95fb6aa741 100644
--- a/drivers/mmc/core/sdio.c
+++ b/drivers/mmc/core/sdio.c
@@ -137,6 +137,7 @@ static int sdio_init_func(struct mmc_card *card, unsigned int fn)
 	 * It is okay to remove the function here even though we hold
 	 * the host lock as we haven't registered the device yet.
 	 */
+	func->card = NULL;
 	sdio_remove_func(func);
 	return ret;
 }
diff --git a/drivers/mmc/core/sdio_bus.c b/drivers/mmc/core/sdio_bus.c
index 266639504a94..da561658bdae 100644
--- a/drivers/mmc/core/sdio_bus.c
+++ b/drivers/mmc/core/sdio_bus.c
@@ -377,11 +377,11 @@ int sdio_add_func(struct sdio_func *func)
  */
 void sdio_remove_func(struct sdio_func *func)
 {
-	of_node_put(func->dev.of_node);
-	if (!sdio_func_present(func))
-		return;
+	if (!sdio_func_present(func)) {
+		device_del(&func->dev);
+	}
 
-	device_del(&func->dev);
+	of_node_put(func->dev.of_node);
 	put_device(&func->dev);
 }
 
diff --git a/drivers/mmc/core/sdio_cis.c b/drivers/mmc/core/sdio_cis.c
index a705ba6eff5b..d374460fba9b 100644
--- a/drivers/mmc/core/sdio_cis.c
+++ b/drivers/mmc/core/sdio_cis.c
@@ -439,6 +439,7 @@ void sdio_free_func_cis(struct sdio_func *func)
 	 * We have now removed the link to the tuples in the
 	 * card structure, so remove the reference.
 	 */
-	put_device(&func->card->dev);
+	if (func->card)
+		put_device(&func->card->dev);
 }
 
-- 
2.25.1