From: Daniel Drake <dsd@laptop.org>
Date: Thu, 17 Dec 2009 23:27:17 +0000 (-0800)
Subject: sdio: fix reference counting in sdio_remove_func()
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=3d10a1ba0d37c8f5fd5afcdda00613fbb8a90bf5;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git

sdio: fix reference counting in sdio_remove_func()

sdio_remove_func() needs to be more careful about reference counting.  It
can be called in error paths where sdio_add_func() has never been called
e.g.  mmc_attach_sdio error path --> mmc_sdio_remove --> sdio_remove_func

Signed-off-by: Daniel Drake <dsd@laptop.org>
Reviewed-by: Matt Fleming <matt@console-pimps.org>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/drivers/mmc/core/sdio_bus.c b/drivers/mmc/core/sdio_bus.c
index d37464e296a5..9e060c87e64d 100644
--- a/drivers/mmc/core/sdio_bus.c
+++ b/drivers/mmc/core/sdio_bus.c
@@ -248,12 +248,15 @@ int sdio_add_func(struct sdio_func *func)
 /*
  * Unregister a SDIO function with the driver model, and
  * (eventually) free it.
+ * This function can be called through error paths where sdio_add_func() was
+ * never executed (because a failure occurred at an earlier point).
  */
 void sdio_remove_func(struct sdio_func *func)
 {
-	if (sdio_func_present(func))
-		device_del(&func->dev);
+	if (!sdio_func_present(func))
+		return;
 
+	device_del(&func->dev);
 	put_device(&func->dev);
 }