linux-kernel - [PATCH v2 04/26] usb: gadget: introduce 'enabled' flag in struct usb

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Message-id: <1442398264-10975-5-git-send-email-r.baldyga@samsung.com>
Date:	Wed, 16 Sep 2015 12:10:42 +0200
From:	Robert Baldyga <r.baldyga@...sung.com>
To:	balbi@...com
Cc:	gregkh@...uxfoundation.org, linux-usb@...r.kernel.org,
	linux-kernel@...r.kernel.org, b.zolnierkie@...sung.com,
	m.szyprowski@...sung.com, andrzej.p@...sung.com,
	Robert Baldyga <r.baldyga@...sung.com>
Subject: [PATCH v2 04/26] usb: gadget: introduce 'enabled' flag in struct usb_ep

This patch introduces 'enabled' flag in struct usb_ep, and modifies
usb_ep_enable() and usb_ep_disable() functions to encapsulate endpoint
enabled/disabled state. It helps to avoid enabling endpoints which are
already enabled, and disabling endpoints which are already disables.

>From now USB functions don't have to remember current endpoint
enable/disable state, as this state is now handled automatically which
makes this API less bug-prone.

Signed-off-by: Robert Baldyga <r.baldyga@...sung.com>
---
 include/linux/usb/gadget.h | 27 +++++++++++++++++++++++++--
 1 file changed, 25 insertions(+), 2 deletions(-)

diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
index 3f299e2..3d583a1 100644
--- a/include/linux/usb/gadget.h
+++ b/include/linux/usb/gadget.h
@@ -215,6 +215,7 @@ struct usb_ep {
 	struct list_head	ep_list;
 	struct usb_ep_caps	caps;
 	bool			claimed;
+	bool			enabled;
 	unsigned		maxpacket:16;
 	unsigned		maxpacket_limit:16;
 	unsigned		max_streams:16;
@@ -264,7 +265,18 @@ static inline void usb_ep_set_maxpacket_limit(struct usb_ep *ep,
  */
 static inline int usb_ep_enable(struct usb_ep *ep)
 {
-	return ep->ops->enable(ep, ep->desc);
+	int ret;
+
+	if (ep->enabled)
+		return 0;
+
+	ret = ep->ops->enable(ep, ep->desc);
+	if (ret)
+		return ret;
+
+	ep->enabled = true;
+
+	return 0;
 }
 
 /**
@@ -281,7 +293,18 @@ static inline int usb_ep_enable(struct usb_ep *ep)
  */
 static inline int usb_ep_disable(struct usb_ep *ep)
 {
-	return ep->ops->disable(ep);
+	int ret;
+
+	if (!ep->enabled)
+		return 0;
+
+	ret = ep->ops->disable(ep);
+	if (ret)
+		return ret;
+
+	ep->enabled = false;
+
+	return 0;
 }
 
 /**
-- 
1.9.1

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