USB: gadget: Drop NULL test on list_entry result

list_entry, which is an alias for container_of, cannot return NULL, as
there is no way to add a NULL value to a doubly linked list.

A simplified version of the semantic match that findds this problem is as
follows:
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@r@
expression x,E;
statement S1,S2;
position p,p1;
@@

*x = list_entry@p(...)
... when != x = E
*if@p1 (x == NULL) S1 else S2
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 25 insertions, 31 deletions

diff --git a/drivers/usb/gadget/amd5536udc.c b/drivers/usb/gadget/amd5536udc.c
index 77352ccc245e..d5b65962dd36 100644
--- a/drivers/usb/gadget/amd5536udc.c
+++ b/drivers/usb/gadget/amd5536udc.c
@@ -2378,40 +2378,34 @@ static irqreturn_t udc_data_in_isr(struct udc *dev, int ep_ix)
                 if (!ep->cancel_transfer && !list_empty(&ep->queue)) {
                         req = list_entry(ep->queue.next,
                                         struct udc_request, queue);
-                        if (req) {
-                                /*
-                                 * length bytes transfered
-                                 * check dma done of last desc. in PPBDU mode
-                                 */
-                                if (use_dma_ppb_du) {
-                                        td = udc_get_last_dma_desc(req);
-                                        if (td) {
-                                                dma_done =
-                                                        AMD_GETBITS(td->status,
-                                                        UDC_DMA_IN_STS_BS);
-                                                /* don't care DMA done */
-                                                req->req.actual =
-                                                        req->req.length;
-                                        }
-                                } else {
-                                        /* assume all bytes transferred */
+                        /*
+                         * length bytes transfered
+                         * check dma done of last desc. in PPBDU mode
+                         */
+                        if (use_dma_ppb_du) {
+                                td = udc_get_last_dma_desc(req);
+                                if (td) {
+                                        dma_done =
+                                                AMD_GETBITS(td->status,
+                                                UDC_DMA_IN_STS_BS);
+                                        /* don't care DMA done */
                                         req->req.actual = req->req.length;
                                 }
+                        } else {
+                                /* assume all bytes transferred */
+                                req->req.actual = req->req.length;
+                        }
 
-                                if (req->req.actual == req->req.length) {
-                                        /* complete req */
-                                        complete_req(ep, req, 0);
-                                        req->dma_going = 0;
-                                        /* further request available ? */
-                                        if (list_empty(&ep->queue)) {
-                                                /* disable interrupt */
-                                                tmp = readl(
-                                                        &dev->regs->ep_irqmsk);
-                                                tmp |= AMD_BIT(ep->num);
-                                                writel(tmp,
-                                                        &dev->regs->ep_irqmsk);
-                                        }
-
+                        if (req->req.actual == req->req.length) {
+                                /* complete req */
+                                complete_req(ep, req, 0);
+                                req->dma_going = 0;
+                                /* further request available ? */
+                                if (list_empty(&ep->queue)) {
+                                        /* disable interrupt */
+                                        tmp = readl(&dev->regs->ep_irqmsk);
+                                        tmp |= AMD_BIT(ep->num);
+                                        writel(tmp, &dev->regs->ep_irqmsk);
                                 }
                         }
                 }