[V2 PATCH] usb: mtu3: fix NULL pointer dereference

[Chunfeng Yun]

Some pointers are dereferenced before successful checks.

Reported-by: Markus Elfring <markus.elfr...@web.de>
Signed-off-by: Chunfeng Yun <chunfeng....@mediatek.com>
---
v2: nothing changed, but abandon another patch
---
 drivers/usb/mtu3/mtu3_gadget.c | 25 ++++++++++++++++++-------
 1 file changed, 18 insertions(+), 7 deletions(-)

diff --git a/drivers/usb/mtu3/mtu3_gadget.c b/drivers/usb/mtu3/mtu3_gadget.c
index f93732e..1689ca8 100644
--- a/drivers/usb/mtu3/mtu3_gadget.c
+++ b/drivers/usb/mtu3/mtu3_gadget.c
@@ -332,14 +332,21 @@ static int mtu3_gadget_queue(struct usb_ep *ep,
 
 static int mtu3_gadget_dequeue(struct usb_ep *ep, struct usb_request *req)
 {
-       struct mtu3_ep *mep = to_mtu3_ep(ep);
-       struct mtu3_request *mreq = to_mtu3_request(req);
+       struct mtu3_ep *mep;
+       struct mtu3_request *mreq;
        struct mtu3_request *r;
+       struct mtu3 *mtu;
        unsigned long flags;
        int ret = 0;
-       struct mtu3 *mtu = mep->mtu;
 
-       if (!ep || !req || mreq->mep != mep)
+       if (!ep || !req)
+               return -EINVAL;
+
+       mep = to_mtu3_ep(ep);
+       mtu = mep->mtu;
+
+       mreq = to_mtu3_request(req);
+       if (mreq->mep != mep)
                return -EINVAL;
 
        dev_dbg(mtu->dev, "%s : req=%p\n", __func__, req);
@@ -373,8 +380,8 @@ static int mtu3_gadget_dequeue(struct usb_ep *ep, struct 
usb_request *req)
  */
 static int mtu3_gadget_ep_set_halt(struct usb_ep *ep, int value)
 {
-       struct mtu3_ep *mep = to_mtu3_ep(ep);
-       struct mtu3 *mtu = mep->mtu;
+       struct mtu3_ep *mep;
+       struct mtu3 *mtu;
        struct mtu3_request *mreq;
        unsigned long flags;
        int ret = 0;
@@ -382,6 +389,9 @@ static int mtu3_gadget_ep_set_halt(struct usb_ep *ep, int 
value)
        if (!ep)
                return -EINVAL;
 
+       mep = to_mtu3_ep(ep);
+       mtu = mep->mtu;
+
        dev_dbg(mtu->dev, "%s : %s...", __func__, ep->name);
 
        spin_lock_irqsave(&mtu->lock, flags);
@@ -422,11 +432,12 @@ static int mtu3_gadget_ep_set_halt(struct usb_ep *ep, int 
value)
 /* Sets the halt feature with the clear requests ignored */
 static int mtu3_gadget_ep_set_wedge(struct usb_ep *ep)
 {
-       struct mtu3_ep *mep = to_mtu3_ep(ep);
+       struct mtu3_ep *mep;
 
        if (!ep)
                return -EINVAL;
 
+       mep = to_mtu3_ep(ep);
        mep->wedged = 1;
 
        return usb_ep_set_halt(ep);
-- 
1.9.1