From 8c756c48ee007733632bfcb141a35e6bcda1b9ac Mon Sep 17 00:00:00 2001
From: Oliver Neukum <oneukum@suse.com>
Date: Wed, 20 Mar 2024 16:30:33 +0100
Subject: [PATCH] dwc3: switch to a global mutex
Patch-mainline: Never, kABI fixup
References: bsc#1220628 CVE-2021-46941

Preserve kABI by replacing the per instance mutex
with a global one.

Signed-off-by: Oliver Neukum <oneukum@suse.comY
---
 drivers/usb/dwc3/core.c |    6 +++---
 drivers/usb/dwc3/core.h |    5 -----
 2 files changed, 3 insertions(+), 8 deletions(-)

--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -49,6 +49,7 @@
 
 #define DWC3_DEFAULT_AUTOSUSPEND_DELAY	5000 /* ms */
 
+static DEFINE_MUTEX(suse_roleswitch_mutex);
 /**
  * dwc3_get_dr_mode - Validates and sets dr_mode
  * @dwc: pointer to our context structure
@@ -123,7 +124,7 @@ static void __dwc3_set_mode(struct work_
 	u32 reg;
 	u32 desired_dr_role;
 
-	mutex_lock(&dwc->mutex);
+	mutex_lock(&suse_roleswitch_mutex);
 
 	spin_lock_irqsave(&dwc->lock, flags);
 	desired_dr_role = dwc->desired_dr_role;
@@ -197,7 +198,7 @@ static void __dwc3_set_mode(struct work_
 		break;
 	}
 out:
-	mutex_unlock(&dwc->mutex);
+	mutex_unlock(&suse_roleswitch_mutex);
 }
 
 void dwc3_set_mode(struct dwc3 *dwc, u32 mode)
@@ -1270,7 +1271,6 @@ static int dwc3_probe(struct platform_de
 	dwc3_cache_hwparams(dwc);
 
 	spin_lock_init(&dwc->lock);
-	mutex_init(&dwc->mutex);
 
 	pm_runtime_get_noresume(dev);
 	pm_runtime_set_active(dev);
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -21,7 +21,6 @@
 
 #include <linux/device.h>
 #include <linux/spinlock.h>
-#include <linux/mutex.h>
 #include <linux/ioport.h>
 #include <linux/list.h>
 #include <linux/bitops.h>
@@ -777,7 +776,6 @@ struct dwc3_scratchpad_array {
  * @scratch_addr: dma address of scratchbuf
  * @ep0_in_setup: one control transfer is completed and enter setup phase
  * @lock: for synchronizing
- * @mutex: for mode switching
  * @dev: pointer to our struct device
  * @xhci: pointer to our xHCI child
  * @event_buffer_list: a list of event buffers
@@ -885,9 +883,6 @@ struct dwc3 {
 	/* device lock */
 	spinlock_t		lock;
 
-	/* mode switching lock */
-	struct mutex		mutex;
-
 	struct device		*dev;
 	struct device		*sysdev;