From 15a2cff2b53a38ff496063d45fdd5e4ed8ab44d9 Mon Sep 17 00:00:00 2001
From: Greg Kroah-Hartman <gregkh@google.com>
Date: Mon, 22 Aug 2022 19:16:15 +0200
Subject: [PATCH] Revert "USB: HCD: Fix URB giveback issue in tasklet function"

This reverts commit 5d952c7ae3393939250c5b5202ec0c1798ebf42e which is
commit 26c6c2f8a907c9e3a2f24990552a4d77235791e6 upstream.

It breaks the Android GKI kernel abi, and is not needed for Android
devices, so revert it for now.  If it is needed for this branch, it can
come back later in an ABI-stable way.

Bug: 161946584
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I7cebceb7c3e1eccf4a36a18dbe0e7ec21378b719
---
 drivers/usb/core/hcd.c  | 26 +++++++++++---------------
 include/linux/usb/hcd.h |  1 -
 2 files changed, 11 insertions(+), 16 deletions(-)

diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index d58098c2af10..fde211519a97 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -1688,6 +1688,7 @@ static void usb_giveback_urb_bh(unsigned long param)
 
 	spin_lock_irq(&bh->lock);
 	bh->running = true;
+ restart:
 	list_replace_init(&bh->head, &local_list);
 	spin_unlock_irq(&bh->lock);
 
@@ -1701,17 +1702,10 @@ static void usb_giveback_urb_bh(unsigned long param)
 		bh->completing_ep = NULL;
 	}
 
-	/*
-	 * giveback new URBs next time to prevent this function
-	 * from not exiting for a long time.
-	 */
+	/* check if there are new URBs to giveback */
 	spin_lock_irq(&bh->lock);
-	if (!list_empty(&bh->head)) {
-		if (bh->high_prio)
-			tasklet_hi_schedule(&bh->bh);
-		else
-			tasklet_schedule(&bh->bh);
-	}
+	if (!list_empty(&bh->head))
+		goto restart;
 	bh->running = false;
 	spin_unlock_irq(&bh->lock);
 }
@@ -1736,7 +1730,7 @@ static void usb_giveback_urb_bh(unsigned long param)
 void usb_hcd_giveback_urb(struct usb_hcd *hcd, struct urb *urb, int status)
 {
 	struct giveback_urb_bh *bh;
-	bool running;
+	bool running, high_prio_bh;
 
 	/* pass status to tasklet via unlinked */
 	if (likely(!urb->unlinked))
@@ -1747,10 +1741,13 @@ void usb_hcd_giveback_urb(struct usb_hcd *hcd, struct urb *urb, int status)
 		return;
 	}
 
-	if (usb_pipeisoc(urb->pipe) || usb_pipeint(urb->pipe))
+	if (usb_pipeisoc(urb->pipe) || usb_pipeint(urb->pipe)) {
 		bh = &hcd->high_prio_bh;
-	else
+		high_prio_bh = true;
+	} else {
 		bh = &hcd->low_prio_bh;
+		high_prio_bh = false;
+	}
 
 	spin_lock(&bh->lock);
 	list_add_tail(&urb->urb_list, &bh->head);
@@ -1759,7 +1756,7 @@ void usb_hcd_giveback_urb(struct usb_hcd *hcd, struct urb *urb, int status)
 
 	if (running)
 		;
-	else if (bh->high_prio)
+	else if (high_prio_bh)
 		tasklet_hi_schedule(&bh->bh);
 	else
 		tasklet_schedule(&bh->bh);
@@ -2799,7 +2796,6 @@ int usb_add_hcd(struct usb_hcd *hcd,
 
 	/* initialize tasklets */
 	init_giveback_urb_bh(&hcd->high_prio_bh);
-	hcd->high_prio_bh.high_prio = true;
 	init_giveback_urb_bh(&hcd->low_prio_bh);
 
 	/* enable irqs just before we start the controller,
diff --git a/include/linux/usb/hcd.h b/include/linux/usb/hcd.h
index d1263dba1508..5ccccd284577 100644
--- a/include/linux/usb/hcd.h
+++ b/include/linux/usb/hcd.h
@@ -67,7 +67,6 @@
 
 struct giveback_urb_bh {
 	bool running;
-	bool high_prio;
 	spinlock_t lock;
 	struct list_head  head;
 	struct tasklet_struct bh;