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Commit 9189a33

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Felipe Balbi
committed
Revert "usb: gadget: u_ether: move hardware transmit to RX NAPI"
This reverts commit 716fb91. That commit caused a regression which would end up in a kernel BUG() as below: [ 101.554300] g_ether gadget: full-speed config #1: CDC Subset/SAFE [ 101.585186] ------------[ cut here ]------------ [ 101.600587] kernel BUG at include/linux/netdevice.h:495! [ 101.615850] Internal error: Oops - BUG: 0 [#1] PREEMPT ARM [ 101.645539] Modules linked in: [ 101.660483] CPU: 0 PID: 0 Comm: swapper Not tainted 3.15.0-rc1+ #104 [ 101.690175] task: c05dc5c8 ti: c05d2000 task.ti: c05d2000 [ 101.705579] PC is at eth_start+0x64/0x8c [ 101.720981] LR is at __netif_schedule+0x7c/0x90 [ 101.736455] pc : [<c0299174>] lr : [<c036a134>] psr: 60000093 [ 101.736455] sp : c05d3d18 ip : c05d3cf8 fp : c05d3d2c [ 101.782340] r10: 00000000 r9 : c196c1f0 r8 : c196c1a0 [ 101.797823] r7 : 00000000 r6 : 00000002 r5 : c1976400 r4 : c1976400 [ 101.828058] r3 : 00000000 r2 : c05d3ce8 r1 : 00000001 r0 : 00000002 [ 101.858722] Flags: nZCv IRQs off FIQs on Mode SVC_32 ISA ARM Segment kernel Reported-by: Robert Jarzmik <[email protected]> Signed-of-by: Felipe Balbi <[email protected]>
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‎drivers/usb/gadget/u_ether.c

Lines changed: 35 additions & 66 deletions
Original file line numberDiff line numberDiff line change
@@ -48,8 +48,6 @@
4848

4949
#define UETH__VERSION "29-May-2008"
5050

51-
#define GETHER_NAPI_WEIGHT 32
52-
5351
struct eth_dev {
5452
/* lock is held while accessing port_usb
5553
*/
@@ -74,7 +72,6 @@ struct eth_dev {
7472
struct sk_buff_head *list);
7573

7674
struct work_struct work;
77-
struct napi_struct rx_napi;
7875

7976
unsigned long todo;
8077
#define WORK_RX_MEMORY 0
@@ -256,16 +253,18 @@ rx_submit(struct eth_dev *dev, struct usb_request *req, gfp_t gfp_flags)
256253
DBG(dev, "rx submit --> %d\n", retval);
257254
if (skb)
258255
dev_kfree_skb_any(skb);
256+
spin_lock_irqsave(&dev->req_lock, flags);
257+
list_add(&req->list, &dev->rx_reqs);
258+
spin_unlock_irqrestore(&dev->req_lock, flags);
259259
}
260260
return retval;
261261
}
262262

263263
static void rx_complete(struct usb_ep *ep, struct usb_request *req)
264264
{
265-
struct sk_buff *skb = req->context;
265+
struct sk_buff *skb = req->context, *skb2;
266266
struct eth_dev *dev = ep->driver_data;
267267
int status = req->status;
268-
bool rx_queue = 0;
269268

270269
switch (status) {
271270

@@ -289,8 +288,30 @@ static void rx_complete(struct usb_ep *ep, struct usb_request *req)
289288
} else {
290289
skb_queue_tail(&dev->rx_frames, skb);
291290
}
292-
if (!status)
293-
rx_queue = 1;
291+
skb = NULL;
292+
293+
skb2 = skb_dequeue(&dev->rx_frames);
294+
while (skb2) {
295+
if (status < 0
296+
|| ETH_HLEN > skb2->len
297+
|| skb2->len > VLAN_ETH_FRAME_LEN) {
298+
dev->net->stats.rx_errors++;
299+
dev->net->stats.rx_length_errors++;
300+
DBG(dev, "rx length %d\n", skb2->len);
301+
dev_kfree_skb_any(skb2);
302+
goto next_frame;
303+
}
304+
skb2->protocol = eth_type_trans(skb2, dev->net);
305+
dev->net->stats.rx_packets++;
306+
dev->net->stats.rx_bytes += skb2->len;
307+
308+
/* no buffer copies needed, unless hardware can't
309+
* use skb buffers.
310+
*/
311+
status = netif_rx(skb2);
312+
next_frame:
313+
skb2 = skb_dequeue(&dev->rx_frames);
314+
}
294315
break;
295316

296317
/* software-driven interface shutdown */
@@ -313,20 +334,22 @@ static void rx_complete(struct usb_ep *ep, struct usb_request *req)
313334
/* FALLTHROUGH */
314335

315336
default:
316-
rx_queue = 1;
317-
dev_kfree_skb_any(skb);
318337
dev->net->stats.rx_errors++;
319338
DBG(dev, "rx status %d\n", status);
320339
break;
321340
}
322341

342+
if (skb)
343+
dev_kfree_skb_any(skb);
344+
if (!netif_running(dev->net)) {
323345
clean:
324346
spin_lock(&dev->req_lock);
325347
list_add(&req->list, &dev->rx_reqs);
326348
spin_unlock(&dev->req_lock);
327-
328-
if (rx_queue && likely(napi_schedule_prep(&dev->rx_napi)))
329-
__napi_schedule(&dev->rx_napi);
349+
req = NULL;
350+
}
351+
if (req)
352+
rx_submit(dev, req, GFP_ATOMIC);
330353
}
331354

332355
static int prealloc(struct list_head *list, struct usb_ep *ep, unsigned n)
@@ -391,24 +414,16 @@ static void rx_fill(struct eth_dev *dev, gfp_t gfp_flags)
391414
{
392415
struct usb_request *req;
393416
unsigned long flags;
394-
int rx_counts = 0;
395417

396418
/* fill unused rxq slots with some skb */
397419
spin_lock_irqsave(&dev->req_lock, flags);
398420
while (!list_empty(&dev->rx_reqs)) {
399-
400-
if (++rx_counts > qlen(dev->gadget, dev->qmult))
401-
break;
402-
403421
req = container_of(dev->rx_reqs.next,
404422
struct usb_request, list);
405423
list_del_init(&req->list);
406424
spin_unlock_irqrestore(&dev->req_lock, flags);
407425

408426
if (rx_submit(dev, req, gfp_flags) < 0) {
409-
spin_lock_irqsave(&dev->req_lock, flags);
410-
list_add(&req->list, &dev->rx_reqs);
411-
spin_unlock_irqrestore(&dev->req_lock, flags);
412427
defer_kevent(dev, WORK_RX_MEMORY);
413428
return;
414429
}
@@ -418,41 +433,6 @@ static void rx_fill(struct eth_dev *dev, gfp_t gfp_flags)
418433
spin_unlock_irqrestore(&dev->req_lock, flags);
419434
}
420435

421-
static int gether_poll(struct napi_struct *napi, int budget)
422-
{
423-
struct eth_dev *dev = container_of(napi, struct eth_dev, rx_napi);
424-
struct sk_buff *skb;
425-
unsigned int work_done = 0;
426-
int status = 0;
427-
428-
while ((skb = skb_dequeue(&dev->rx_frames))) {
429-
if (status < 0
430-
|| ETH_HLEN > skb->len
431-
|| skb->len > VLAN_ETH_FRAME_LEN) {
432-
dev->net->stats.rx_errors++;
433-
dev->net->stats.rx_length_errors++;
434-
DBG(dev, "rx length %d\n", skb->len);
435-
dev_kfree_skb_any(skb);
436-
continue;
437-
}
438-
skb->protocol = eth_type_trans(skb, dev->net);
439-
dev->net->stats.rx_packets++;
440-
dev->net->stats.rx_bytes += skb->len;
441-
442-
status = netif_rx_ni(skb);
443-
}
444-
445-
if (netif_running(dev->net)) {
446-
rx_fill(dev, GFP_KERNEL);
447-
work_done++;
448-
}
449-
450-
if (work_done < budget)
451-
napi_complete(&dev->rx_napi);
452-
453-
return work_done;
454-
}
455-
456436
static void eth_work(struct work_struct *work)
457437
{
458438
struct eth_dev *dev = container_of(work, struct eth_dev, work);
@@ -645,7 +625,6 @@ static void eth_start(struct eth_dev *dev, gfp_t gfp_flags)
645625
/* and open the tx floodgates */
646626
atomic_set(&dev->tx_qlen, 0);
647627
netif_wake_queue(dev->net);
648-
napi_enable(&dev->rx_napi);
649628
}
650629

651630
static int eth_open(struct net_device *net)
@@ -672,7 +651,6 @@ static int eth_stop(struct net_device *net)
672651
unsigned long flags;
673652

674653
VDBG(dev, "%s\n", __func__);
675-
napi_disable(&dev->rx_napi);
676654
netif_stop_queue(net);
677655

678656
DBG(dev, "stop stats: rx/tx %ld/%ld, errs %ld/%ld\n",
@@ -790,7 +768,6 @@ struct eth_dev *gether_setup_name(struct usb_gadget *g,
790768
return ERR_PTR(-ENOMEM);
791769

792770
dev = netdev_priv(net);
793-
netif_napi_add(net, &dev->rx_napi, gether_poll, GETHER_NAPI_WEIGHT);
794771
spin_lock_init(&dev->lock);
795772
spin_lock_init(&dev->req_lock);
796773
INIT_WORK(&dev->work, eth_work);
@@ -853,7 +830,6 @@ struct net_device *gether_setup_name_default(const char *netname)
853830
return ERR_PTR(-ENOMEM);
854831

855832
dev = netdev_priv(net);
856-
netif_napi_add(net, &dev->rx_napi, gether_poll, GETHER_NAPI_WEIGHT);
857833
spin_lock_init(&dev->lock);
858834
spin_lock_init(&dev->req_lock);
859835
INIT_WORK(&dev->work, eth_work);
@@ -1137,7 +1113,6 @@ void gether_disconnect(struct gether *link)
11371113
{
11381114
struct eth_dev *dev = link->ioport;
11391115
struct usb_request *req;
1140-
struct sk_buff *skb;
11411116

11421117
WARN_ON(!dev);
11431118
if (!dev)
@@ -1164,12 +1139,6 @@ void gether_disconnect(struct gether *link)
11641139
spin_lock(&dev->req_lock);
11651140
}
11661141
spin_unlock(&dev->req_lock);
1167-
1168-
spin_lock(&dev->rx_frames.lock);
1169-
while ((skb = __skb_dequeue(&dev->rx_frames)))
1170-
dev_kfree_skb_any(skb);
1171-
spin_unlock(&dev->rx_frames.lock);
1172-
11731142
link->in_ep->driver_data = NULL;
11741143
link->in_ep->desc = NULL;
11751144

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