forked from ~ljy/RK356X_SDK_RELEASE
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hc
2024-02-20 ea08eeccae9297f7aabd2ef7f0c2517ac4549acc 
 kernel/drivers/net/xen-netback/netback.c
....@@ -96,6 +96,13 @@
9696 module_param_named(hash_cache_size, xenvif_hash_cache_size, uint, 0644);
9797 MODULE_PARM_DESC(hash_cache_size, "Number of flows in the hash cache");
9898 
99
+/* The module parameter tells that we have to put data
100
+ * for xen-netfront with the XDP_PACKET_HEADROOM offset
101
+ * needed for XDP processing
102
+ */
103
+bool provides_xdp_headroom = true;
104
+module_param(provides_xdp_headroom, bool, 0644);
105
+
99106 static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,
100107 			       u8 status);
101108 
....@@ -104,6 +111,8 @@
104111 			     unsigned int extra_count,
105112 			     s8       st);
106113 static void push_tx_responses(struct xenvif_queue *queue);
114
+
115
+static void xenvif_idx_unmap(struct xenvif_queue *queue, u16 pending_idx);
107116 
108117 static inline int tx_work_todo(struct xenvif_queue *queue);
109118 
....@@ -136,12 +145,12 @@
136145 
137146 static u16 frag_get_pending_idx(skb_frag_t *frag)
138147 {
139
-	return (u16)frag->page_offset;
148
+	return (u16)skb_frag_off(frag);
140149 }
141150 
142151 static void frag_set_pending_idx(skb_frag_t *frag, u16 pending_idx)
143152 {
144
-	frag->page_offset = pending_idx;
153
+	skb_frag_off_set(frag, pending_idx);
145154 }
146155 
147156 static inline pending_ring_idx_t pending_index(unsigned i)
....@@ -323,10 +332,14 @@
323332 
324333 
325334 struct xenvif_tx_cb {
326
-	u16 pending_idx;
335
+	u16 copy_pending_idx[XEN_NETBK_LEGACY_SLOTS_MAX + 1];
336
+	u8 copy_count;
337
+	u32 split_mask;
327338 };
328339 
329340 #define XENVIF_TX_CB(skb) ((struct xenvif_tx_cb *)(skb)->cb)
341
+#define copy_pending_idx(skb, i) (XENVIF_TX_CB(skb)->copy_pending_idx[i])
342
+#define copy_count(skb) (XENVIF_TX_CB(skb)->copy_count)
330343 
331344 static inline void xenvif_tx_create_map_op(struct xenvif_queue *queue,
332345 					   u16 pending_idx,
....@@ -349,6 +362,8 @@
349362 	struct sk_buff *skb =
350363 		alloc_skb(size + NET_SKB_PAD + NET_IP_ALIGN,
351364 			  GFP_ATOMIC | __GFP_NOWARN);
365
+
366
+	BUILD_BUG_ON(sizeof(*XENVIF_TX_CB(skb)) > sizeof(skb->cb));
352367 	if (unlikely(skb == NULL))
353368 		return NULL;
354369 
....@@ -361,39 +376,112 @@
361376 	return skb;
362377 }
363378 
364
-static struct gnttab_map_grant_ref *xenvif_get_requests(struct xenvif_queue *queue,
365
-							struct sk_buff *skb,
366
-							struct xen_netif_tx_request *txp,
367
-							struct gnttab_map_grant_ref *gop,
368
-							unsigned int frag_overflow,
369
-							struct sk_buff *nskb)
379
+static void xenvif_get_requests(struct xenvif_queue *queue,
380
+				struct sk_buff *skb,
381
+				struct xen_netif_tx_request *first,
382
+				struct xen_netif_tx_request *txfrags,
383
+			        unsigned *copy_ops,
384
+			        unsigned *map_ops,
385
+				unsigned int frag_overflow,
386
+				struct sk_buff *nskb,
387
+				unsigned int extra_count,
388
+				unsigned int data_len)
370389 {
371390 	struct skb_shared_info *shinfo = skb_shinfo(skb);
372391 	skb_frag_t *frags = shinfo->frags;
373
-	u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
374
-	int start;
392
+	u16 pending_idx;
375393 	pending_ring_idx_t index;
376394 	unsigned int nr_slots;
395
+	struct gnttab_copy *cop = queue->tx_copy_ops + *copy_ops;
396
+	struct gnttab_map_grant_ref *gop = queue->tx_map_ops + *map_ops;
397
+	struct xen_netif_tx_request *txp = first;
377398 
378
-	nr_slots = shinfo->nr_frags;
399
+	nr_slots = shinfo->nr_frags + frag_overflow + 1;
379400 
380
-	/* Skip first skb fragment if it is on same page as header fragment. */
381
-	start = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx);
401
+	copy_count(skb) = 0;
402
+	XENVIF_TX_CB(skb)->split_mask = 0;
382403 
383
-	for (shinfo->nr_frags = start; shinfo->nr_frags < nr_slots;
384
-	     shinfo->nr_frags++, txp++, gop++) {
385
-		index = pending_index(queue->pending_cons++);
404
+	/* Create copy ops for exactly data_len bytes into the skb head. */
405
+	__skb_put(skb, data_len);
406
+	while (data_len > 0) {
407
+		int amount = data_len > txp->size ? txp->size : data_len;
408
+		bool split = false;
409
+
410
+		cop->source.u.ref = txp->gref;
411
+		cop->source.domid = queue->vif->domid;
412
+		cop->source.offset = txp->offset;
413
+
414
+		cop->dest.domid = DOMID_SELF;
415
+		cop->dest.offset = (offset_in_page(skb->data +
416
+						   skb_headlen(skb) -
417
+						   data_len)) & ~XEN_PAGE_MASK;
418
+		cop->dest.u.gmfn = virt_to_gfn(skb->data + skb_headlen(skb)
419
+				               - data_len);
420
+
421
+		/* Don't cross local page boundary! */
422
+		if (cop->dest.offset + amount > XEN_PAGE_SIZE) {
423
+			amount = XEN_PAGE_SIZE - cop->dest.offset;
424
+			XENVIF_TX_CB(skb)->split_mask |= 1U << copy_count(skb);
425
+			split = true;
426
+		}
427
+
428
+		cop->len = amount;
429
+		cop->flags = GNTCOPY_source_gref;
430
+
431
+		index = pending_index(queue->pending_cons);
386432 		pending_idx = queue->pending_ring[index];
387
-		xenvif_tx_create_map_op(queue, pending_idx, txp, 0, gop);
388
-		frag_set_pending_idx(&frags[shinfo->nr_frags], pending_idx);
433
+		callback_param(queue, pending_idx).ctx = NULL;
434
+		copy_pending_idx(skb, copy_count(skb)) = pending_idx;
435
+		if (!split)
436
+			copy_count(skb)++;
437
+
438
+		cop++;
439
+		data_len -= amount;
440
+
441
+		if (amount == txp->size) {
442
+			/* The copy op covered the full tx_request */
443
+
444
+			memcpy(&queue->pending_tx_info[pending_idx].req,
445
+			       txp, sizeof(*txp));
446
+			queue->pending_tx_info[pending_idx].extra_count =
447
+				(txp == first) ? extra_count : 0;
448
+
449
+			if (txp == first)
450
+				txp = txfrags;
451
+			else
452
+				txp++;
453
+			queue->pending_cons++;
454
+			nr_slots--;
455
+		} else {
456
+			/* The copy op partially covered the tx_request.
457
+			 * The remainder will be mapped or copied in the next
458
+			 * iteration.
459
+			 */
460
+			txp->offset += amount;
461
+			txp->size -= amount;
462
+		}
389463 	}
390464 
391
-	if (frag_overflow) {
465
+	for (shinfo->nr_frags = 0; nr_slots > 0 && shinfo->nr_frags < MAX_SKB_FRAGS;
466
+	     shinfo->nr_frags++, gop++, nr_slots--) {
467
+		index = pending_index(queue->pending_cons++);
468
+		pending_idx = queue->pending_ring[index];
469
+		xenvif_tx_create_map_op(queue, pending_idx, txp,
470
+				        txp == first ? extra_count : 0, gop);
471
+		frag_set_pending_idx(&frags[shinfo->nr_frags], pending_idx);
472
+
473
+		if (txp == first)
474
+			txp = txfrags;
475
+		else
476
+			txp++;
477
+	}
478
+
479
+	if (nr_slots > 0) {
392480 
393481 		shinfo = skb_shinfo(nskb);
394482 		frags = shinfo->frags;
395483 
396
-		for (shinfo->nr_frags = 0; shinfo->nr_frags < frag_overflow;
484
+		for (shinfo->nr_frags = 0; shinfo->nr_frags < nr_slots;
397485 		     shinfo->nr_frags++, txp++, gop++) {
398486 			index = pending_index(queue->pending_cons++);
399487 			pending_idx = queue->pending_ring[index];
....@@ -404,9 +492,15 @@
404492 		}
405493 
406494 		skb_shinfo(skb)->frag_list = nskb;
495
+	} else if (nskb) {
496
+		/* A frag_list skb was allocated but it is no longer needed
497
+		 * because enough slots were converted to copy ops above.
498
+		 */
499
+		kfree_skb(nskb);
407500 	}
408501 
409
-	return gop;
502
+	(*copy_ops) = cop - queue->tx_copy_ops;
503
+	(*map_ops) = gop - queue->tx_map_ops;
410504 }
411505 
412506 static inline void xenvif_grant_handle_set(struct xenvif_queue *queue,
....@@ -442,7 +536,7 @@
442536 			       struct gnttab_copy **gopp_copy)
443537 {
444538 	struct gnttab_map_grant_ref *gop_map = *gopp_map;
445
-	u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
539
+	u16 pending_idx;
446540 	/* This always points to the shinfo of the skb being checked, which
447541 	 * could be either the first or the one on the frag_list
448542 	 */
....@@ -453,24 +547,44 @@
453547 	struct skb_shared_info *first_shinfo = NULL;
454548 	int nr_frags = shinfo->nr_frags;
455549 	const bool sharedslot = nr_frags &&
456
-				frag_get_pending_idx(&shinfo->frags[0]) == pending_idx;
457
-	int i, err;
550
+				frag_get_pending_idx(&shinfo->frags[0]) ==
551
+				    copy_pending_idx(skb, copy_count(skb) - 1);
552
+	int i, err = 0;
458553 
459
-	/* Check status of header. */
460
-	err = (*gopp_copy)->status;
461
-	if (unlikely(err)) {
462
-		if (net_ratelimit())
463
-			netdev_dbg(queue->vif->dev,
464
-				   "Grant copy of header failed! status: %d pending_idx: %u ref: %u\n",
465
-				   (*gopp_copy)->status,
466
-				   pending_idx,
467
-				   (*gopp_copy)->source.u.ref);
468
-		/* The first frag might still have this slot mapped */
469
-		if (!sharedslot)
470
-			xenvif_idx_release(queue, pending_idx,
471
-					   XEN_NETIF_RSP_ERROR);
554
+	for (i = 0; i < copy_count(skb); i++) {
555
+		int newerr;
556
+
557
+		/* Check status of header. */
558
+		pending_idx = copy_pending_idx(skb, i);
559
+
560
+		newerr = (*gopp_copy)->status;
561
+
562
+		/* Split copies need to be handled together. */
563
+		if (XENVIF_TX_CB(skb)->split_mask & (1U << i)) {
564
+			(*gopp_copy)++;
565
+			if (!newerr)
566
+				newerr = (*gopp_copy)->status;
567
+		}
568
+		if (likely(!newerr)) {
569
+			/* The first frag might still have this slot mapped */
570
+			if (i < copy_count(skb) - 1 || !sharedslot)
571
+				xenvif_idx_release(queue, pending_idx,
572
+						   XEN_NETIF_RSP_OKAY);
573
+		} else {
574
+			err = newerr;
575
+			if (net_ratelimit())
576
+				netdev_dbg(queue->vif->dev,
577
+					   "Grant copy of header failed! status: %d pending_idx: %u ref: %u\n",
578
+					   (*gopp_copy)->status,
579
+					   pending_idx,
580
+					   (*gopp_copy)->source.u.ref);
581
+			/* The first frag might still have this slot mapped */
582
+			if (i < copy_count(skb) - 1 || !sharedslot)
583
+				xenvif_idx_release(queue, pending_idx,
584
+						   XEN_NETIF_RSP_ERROR);
585
+		}
586
+		(*gopp_copy)++;
472587 	}
473
-	(*gopp_copy)++;
474588 
475589 check_frags:
476590 	for (i = 0; i < nr_frags; i++, gop_map++) {
....@@ -516,14 +630,6 @@
516630 		/* Not the first error? Preceding frags already invalidated. */
517631 		if (err)
518632 			continue;
519
-
520
-		/* First error: if the header haven't shared a slot with the
521
-		 * first frag, release it as well.
522
-		 */
523
-		if (!sharedslot)
524
-			xenvif_idx_release(queue,
525
-					   XENVIF_TX_CB(skb)->pending_idx,
526
-					   XEN_NETIF_RSP_OKAY);
527633 
528634 		/* Invalidate preceding fragments of this skb. */
529635 		for (j = 0; j < i; j++) {
....@@ -794,7 +900,6 @@
794900 				     unsigned *copy_ops,
795901 				     unsigned *map_ops)
796902 {
797
-	struct gnttab_map_grant_ref *gop = queue->tx_map_ops;
798903 	struct sk_buff *skb, *nskb;
799904 	int ret;
800905 	unsigned int frag_overflow;
....@@ -876,8 +981,12 @@
876981 			continue;
877982 		}
878983 
984
+		data_len = (txreq.size > XEN_NETBACK_TX_COPY_LEN) ?
985
+			XEN_NETBACK_TX_COPY_LEN : txreq.size;
986
+
879987 		ret = xenvif_count_requests(queue, &txreq, extra_count,
880988 					    txfrags, work_to_do);
989
+
881990 		if (unlikely(ret < 0))
882991 			break;
883992 
....@@ -892,10 +1001,8 @@
8921001 
8931002 		/* No crossing a page as the payload mustn't fragment. */
8941003 		if (unlikely((txreq.offset + txreq.size) > XEN_PAGE_SIZE)) {
895
-			netdev_err(queue->vif->dev,
896
-				   "txreq.offset: %u, size: %u, end: %lu\n",
897
-				   txreq.offset, txreq.size,
898
-				   (unsigned long)(txreq.offset&~XEN_PAGE_MASK) + txreq.size);
1004
+			netdev_err(queue->vif->dev, "Cross page boundary, txreq.offset: %u, size: %u\n",
1005
+				   txreq.offset, txreq.size);
8991006 			xenvif_fatal_tx_err(queue->vif);
9001007 			break;
9011008 		}
....@@ -903,9 +1010,8 @@
9031010 		index = pending_index(queue->pending_cons);
9041011 		pending_idx = queue->pending_ring[index];
9051012 
906
-		data_len = (txreq.size > XEN_NETBACK_TX_COPY_LEN &&
907
-			    ret < XEN_NETBK_LEGACY_SLOTS_MAX) ?
908
-			XEN_NETBACK_TX_COPY_LEN : txreq.size;
1013
+		if (ret >= XEN_NETBK_LEGACY_SLOTS_MAX - 1 && data_len < txreq.size)
1014
+			data_len = txreq.size;
9091015 
9101016 		skb = xenvif_alloc_skb(data_len);
9111017 		if (unlikely(skb == NULL)) {
....@@ -916,8 +1022,6 @@
9161022 		}
9171023 
9181024 		skb_shinfo(skb)->nr_frags = ret;
919
-		if (data_len < txreq.size)
920
-			skb_shinfo(skb)->nr_frags++;
9211025 		/* At this point shinfo->nr_frags is in fact the number of
9221026 		 * slots, which can be as large as XEN_NETBK_LEGACY_SLOTS_MAX.
9231027 		 */
....@@ -979,54 +1083,19 @@
9791083 					     type);
9801084 		}
9811085 
982
-		XENVIF_TX_CB(skb)->pending_idx = pending_idx;
983
-
984
-		__skb_put(skb, data_len);
985
-		queue->tx_copy_ops[*copy_ops].source.u.ref = txreq.gref;
986
-		queue->tx_copy_ops[*copy_ops].source.domid = queue->vif->domid;
987
-		queue->tx_copy_ops[*copy_ops].source.offset = txreq.offset;
988
-
989
-		queue->tx_copy_ops[*copy_ops].dest.u.gmfn =
990
-			virt_to_gfn(skb->data);
991
-		queue->tx_copy_ops[*copy_ops].dest.domid = DOMID_SELF;
992
-		queue->tx_copy_ops[*copy_ops].dest.offset =
993
-			offset_in_page(skb->data) & ~XEN_PAGE_MASK;
994
-
995
-		queue->tx_copy_ops[*copy_ops].len = data_len;
996
-		queue->tx_copy_ops[*copy_ops].flags = GNTCOPY_source_gref;
997
-
998
-		(*copy_ops)++;
999
-
1000
-		if (data_len < txreq.size) {
1001
-			frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
1002
-					     pending_idx);
1003
-			xenvif_tx_create_map_op(queue, pending_idx, &txreq,
1004
-						extra_count, gop);
1005
-			gop++;
1006
-		} else {
1007
-			frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
1008
-					     INVALID_PENDING_IDX);
1009
-			memcpy(&queue->pending_tx_info[pending_idx].req,
1010
-			       &txreq, sizeof(txreq));
1011
-			queue->pending_tx_info[pending_idx].extra_count =
1012
-				extra_count;
1013
-		}
1014
-
1015
-		queue->pending_cons++;
1016
-
1017
-		gop = xenvif_get_requests(queue, skb, txfrags, gop,
1018
-				          frag_overflow, nskb);
1086
+		xenvif_get_requests(queue, skb, &txreq, txfrags, copy_ops,
1087
+				    map_ops, frag_overflow, nskb, extra_count,
1088
+				    data_len);
10191089 
10201090 		__skb_queue_tail(&queue->tx_queue, skb);
10211091 
10221092 		queue->tx.req_cons = idx;
10231093 
1024
-		if (((gop-queue->tx_map_ops) >= ARRAY_SIZE(queue->tx_map_ops)) ||
1094
+		if ((*map_ops >= ARRAY_SIZE(queue->tx_map_ops)) ||
10251095 		    (*copy_ops >= ARRAY_SIZE(queue->tx_copy_ops)))
10261096 			break;
10271097 	}
10281098 
1029
-	(*map_ops) = gop - queue->tx_map_ops;
10301099 	return;
10311100 }
10321101 
....@@ -1061,7 +1130,7 @@
10611130 			int j;
10621131 			skb->truesize += skb->data_len;
10631132 			for (j = 0; j < i; j++)
1064
-				put_page(frags[j].page.p);
1133
+				put_page(skb_frag_page(&frags[j]));
10651134 			return -ENOMEM;
10661135 		}
10671136 
....@@ -1073,8 +1142,8 @@
10731142 			BUG();
10741143 
10751144 		offset += len;
1076
-		frags[i].page.p = page;
1077
-		frags[i].page_offset = 0;
1145
+		__skb_frag_set_page(&frags[i], page);
1146
+		skb_frag_off_set(&frags[i], 0);
10781147 		skb_frag_size_set(&frags[i], len);
10791148 	}
10801149 
....@@ -1105,9 +1174,8 @@
11051174 	while ((skb = __skb_dequeue(&queue->tx_queue)) != NULL) {
11061175 		struct xen_netif_tx_request *txp;
11071176 		u16 pending_idx;
1108
-		unsigned data_len;
11091177 
1110
-		pending_idx = XENVIF_TX_CB(skb)->pending_idx;
1178
+		pending_idx = copy_pending_idx(skb, 0);
11111179 		txp = &queue->pending_tx_info[pending_idx].req;
11121180 
11131181 		/* Check the remap error code. */
....@@ -1124,18 +1192,6 @@
11241192 			}
11251193 			kfree_skb(skb);
11261194 			continue;
1127
-		}
1128
-
1129
-		data_len = skb->len;
1130
-		callback_param(queue, pending_idx).ctx = NULL;
1131
-		if (data_len < txp->size) {
1132
-			/* Append the packet payload as a fragment. */
1133
-			txp->offset += data_len;
1134
-			txp->size -= data_len;
1135
-		} else {
1136
-			/* Schedule a response immediately. */
1137
-			xenvif_idx_release(queue, pending_idx,
1138
-					   XEN_NETIF_RSP_OKAY);
11391195 		}
11401196 
11411197 		if (txp->flags & XEN_NETTXF_csum_blank)
....@@ -1175,15 +1231,24 @@
11751231 			continue;
11761232 		}
11771233 
1178
-		skb_probe_transport_header(skb, 0);
1234
+		skb_probe_transport_header(skb);
11791235 
11801236 		/* If the packet is GSO then we will have just set up the
11811237 		 * transport header offset in checksum_setup so it's now
11821238 		 * straightforward to calculate gso_segs.
11831239 		 */
11841240 		if (skb_is_gso(skb)) {
1185
-			int mss = skb_shinfo(skb)->gso_size;
1186
-			int hdrlen = skb_transport_header(skb) -
1241
+			int mss, hdrlen;
1242
+
1243
+			/* GSO implies having the L4 header. */
1244
+			WARN_ON_ONCE(!skb_transport_header_was_set(skb));
1245
+			if (unlikely(!skb_transport_header_was_set(skb))) {
1246
+				kfree_skb(skb);
1247
+				continue;
1248
+			}
1249
+
1250
+			mss = skb_shinfo(skb)->gso_size;
1251
+			hdrlen = skb_transport_header(skb) -
11871252 				skb_mac_header(skb) +
11881253 				tcp_hdrlen(skb);
11891254 
....@@ -1314,7 +1379,7 @@
13141379 /* Called after netfront has transmitted */
13151380 int xenvif_tx_action(struct xenvif_queue *queue, int budget)
13161381 {
1317
-	unsigned nr_mops, nr_cops = 0;
1382
+	unsigned nr_mops = 0, nr_cops = 0;
13181383 	int work_done, ret;
13191384 
13201385 	if (unlikely(!tx_work_todo(queue)))
....@@ -1401,7 +1466,7 @@
14011466 		notify_remote_via_irq(queue->tx_irq);
14021467 }
14031468 
1404
-void xenvif_idx_unmap(struct xenvif_queue *queue, u16 pending_idx)
1469
+static void xenvif_idx_unmap(struct xenvif_queue *queue, u16 pending_idx)
14051470 {
14061471 	int ret;
14071472 	struct gnttab_unmap_grant_ref tx_unmap_op;
....@@ -1456,7 +1521,7 @@
14561521 	void *addr;
14571522 	struct xen_netif_tx_sring *txs;
14581523 	struct xen_netif_rx_sring *rxs;
1459
-
1524
+	RING_IDX rsp_prod, req_prod;
14601525 	int err = -ENOMEM;
14611526 
14621527 	err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif),
....@@ -1465,7 +1530,14 @@
14651530 		goto err;
14661531 
14671532 	txs = (struct xen_netif_tx_sring *)addr;
1468
-	BACK_RING_INIT(&queue->tx, txs, XEN_PAGE_SIZE);
1533
+	rsp_prod = READ_ONCE(txs->rsp_prod);
1534
+	req_prod = READ_ONCE(txs->req_prod);
1535
+
1536
+	BACK_RING_ATTACH(&queue->tx, txs, rsp_prod, XEN_PAGE_SIZE);
1537
+
1538
+	err = -EIO;
1539
+	if (req_prod - rsp_prod > RING_SIZE(&queue->tx))
1540
+		goto err;
14691541 
14701542 	err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif),
14711543 				     &rx_ring_ref, 1, &addr);
....@@ -1473,7 +1545,14 @@
14731545 		goto err;
14741546 
14751547 	rxs = (struct xen_netif_rx_sring *)addr;
1476
-	BACK_RING_INIT(&queue->rx, rxs, XEN_PAGE_SIZE);
1548
+	rsp_prod = READ_ONCE(rxs->rsp_prod);
1549
+	req_prod = READ_ONCE(rxs->req_prod);
1550
+
1551
+	BACK_RING_ATTACH(&queue->rx, rxs, rsp_prod, XEN_PAGE_SIZE);
1552
+
1553
+	err = -EIO;
1554
+	if (req_prod - rsp_prod > RING_SIZE(&queue->rx))
1555
+		goto err;
14771556 
14781557 	return 0;
14791558 
....@@ -1663,9 +1742,6 @@
16631742 
16641743 #ifdef CONFIG_DEBUG_FS
16651744 	xen_netback_dbg_root = debugfs_create_dir("xen-netback", NULL);
1666
-	if (IS_ERR_OR_NULL(xen_netback_dbg_root))
1667
-		pr_warn("Init of debugfs returned %ld!\n",
1668
-			PTR_ERR(xen_netback_dbg_root));
16691745 #endif /* CONFIG_DEBUG_FS */
16701746 
16711747 	return 0;
....@@ -1679,8 +1755,7 @@
16791755 static void __exit netback_fini(void)
16801756 {
16811757 #ifdef CONFIG_DEBUG_FS
1682
-	if (!IS_ERR_OR_NULL(xen_netback_dbg_root))
1683
-		debugfs_remove_recursive(xen_netback_dbg_root);
1758
+	debugfs_remove_recursive(xen_netback_dbg_root);
16841759 #endif /* CONFIG_DEBUG_FS */
16851760 	xenvif_xenbus_fini();
16861761 }