1 /* SPDX-License-Identifier: GPL-2.0 */
2 /* Copyright(c) 2013 - 2018 Intel Corporation. */
3 
4 #ifndef _IAVF_TXRX_H_
5 #define _IAVF_TXRX_H_
6 
7 /* Interrupt Throttling and Rate Limiting Goodies */
8 #define IAVF_DEFAULT_IRQ_WORK      256
9 
10 /* The datasheet for the X710 and XL710 indicate that the maximum value for
11  * the ITR is 8160usec which is then called out as 0xFF0 with a 2usec
12  * resolution. 8160 is 0x1FE0 when written out in hex. So instead of storing
13  * the register value which is divided by 2 lets use the actual values and
14  * avoid an excessive amount of translation.
15  */
16 #define IAVF_ITR_DYNAMIC	0x8000	/* use top bit as a flag */
17 #define IAVF_ITR_MASK		0x1FFE	/* mask for ITR register value */
18 #define IAVF_ITR_100K		    10	/* all values below must be even */
19 #define IAVF_ITR_50K		    20
20 #define IAVF_ITR_20K		    50
21 #define IAVF_ITR_18K		    60
22 #define IAVF_ITR_8K		   122
23 #define IAVF_MAX_ITR		  8160	/* maximum value as per datasheet */
24 #define ITR_TO_REG(setting) ((setting) & ~IAVF_ITR_DYNAMIC)
25 #define ITR_REG_ALIGN(setting) __ALIGN_MASK(setting, ~IAVF_ITR_MASK)
26 #define ITR_IS_DYNAMIC(setting) (!!((setting) & IAVF_ITR_DYNAMIC))
27 
28 #define IAVF_ITR_RX_DEF		(IAVF_ITR_20K | IAVF_ITR_DYNAMIC)
29 #define IAVF_ITR_TX_DEF		(IAVF_ITR_20K | IAVF_ITR_DYNAMIC)
30 
31 /* 0x40 is the enable bit for interrupt rate limiting, and must be set if
32  * the value of the rate limit is non-zero
33  */
34 #define INTRL_ENA                  BIT(6)
35 #define IAVF_MAX_INTRL             0x3B    /* reg uses 4 usec resolution */
36 #define INTRL_REG_TO_USEC(intrl) ((intrl & ~INTRL_ENA) << 2)
37 #define INTRL_USEC_TO_REG(set) ((set) ? ((set) >> 2) | INTRL_ENA : 0)
38 #define IAVF_INTRL_8K              125     /* 8000 ints/sec */
39 #define IAVF_INTRL_62K             16      /* 62500 ints/sec */
40 #define IAVF_INTRL_83K             12      /* 83333 ints/sec */
41 
42 #define IAVF_QUEUE_END_OF_LIST 0x7FF
43 
44 /* this enum matches hardware bits and is meant to be used by DYN_CTLN
45  * registers and QINT registers or more generally anywhere in the manual
46  * mentioning ITR_INDX, ITR_NONE cannot be used as an index 'n' into any
47  * register but instead is a special value meaning "don't update" ITR0/1/2.
48  */
49 enum iavf_dyn_idx_t {
50 	IAVF_IDX_ITR0 = 0,
51 	IAVF_IDX_ITR1 = 1,
52 	IAVF_IDX_ITR2 = 2,
53 	IAVF_ITR_NONE = 3	/* ITR_NONE must not be used as an index */
54 };
55 
56 /* these are indexes into ITRN registers */
57 #define IAVF_RX_ITR    IAVF_IDX_ITR0
58 #define IAVF_TX_ITR    IAVF_IDX_ITR1
59 #define IAVF_PE_ITR    IAVF_IDX_ITR2
60 
61 /* Supported RSS offloads */
62 #define IAVF_DEFAULT_RSS_HENA ( \
63 	BIT_ULL(IAVF_FILTER_PCTYPE_NONF_IPV4_UDP) | \
64 	BIT_ULL(IAVF_FILTER_PCTYPE_NONF_IPV4_SCTP) | \
65 	BIT_ULL(IAVF_FILTER_PCTYPE_NONF_IPV4_TCP) | \
66 	BIT_ULL(IAVF_FILTER_PCTYPE_NONF_IPV4_OTHER) | \
67 	BIT_ULL(IAVF_FILTER_PCTYPE_FRAG_IPV4) | \
68 	BIT_ULL(IAVF_FILTER_PCTYPE_NONF_IPV6_UDP) | \
69 	BIT_ULL(IAVF_FILTER_PCTYPE_NONF_IPV6_TCP) | \
70 	BIT_ULL(IAVF_FILTER_PCTYPE_NONF_IPV6_SCTP) | \
71 	BIT_ULL(IAVF_FILTER_PCTYPE_NONF_IPV6_OTHER) | \
72 	BIT_ULL(IAVF_FILTER_PCTYPE_FRAG_IPV6) | \
73 	BIT_ULL(IAVF_FILTER_PCTYPE_L2_PAYLOAD))
74 
75 #define IAVF_DEFAULT_RSS_HENA_EXPANDED (IAVF_DEFAULT_RSS_HENA | \
76 	BIT_ULL(IAVF_FILTER_PCTYPE_NONF_IPV4_TCP_SYN_NO_ACK) | \
77 	BIT_ULL(IAVF_FILTER_PCTYPE_NONF_UNICAST_IPV4_UDP) | \
78 	BIT_ULL(IAVF_FILTER_PCTYPE_NONF_MULTICAST_IPV4_UDP) | \
79 	BIT_ULL(IAVF_FILTER_PCTYPE_NONF_IPV6_TCP_SYN_NO_ACK) | \
80 	BIT_ULL(IAVF_FILTER_PCTYPE_NONF_UNICAST_IPV6_UDP) | \
81 	BIT_ULL(IAVF_FILTER_PCTYPE_NONF_MULTICAST_IPV6_UDP))
82 
83 /* Supported Rx Buffer Sizes (a multiple of 128) */
84 #define IAVF_RXBUFFER_256   256
85 #define IAVF_RXBUFFER_1536  1536  /* 128B aligned standard Ethernet frame */
86 #define IAVF_RXBUFFER_2048  2048
87 #define IAVF_RXBUFFER_3072  3072  /* Used for large frames w/ padding */
88 #define IAVF_MAX_RXBUFFER   9728  /* largest size for single descriptor */
89 
90 /* NOTE: netdev_alloc_skb reserves up to 64 bytes, NET_IP_ALIGN means we
91  * reserve 2 more, and skb_shared_info adds an additional 384 bytes more,
92  * this adds up to 512 bytes of extra data meaning the smallest allocation
93  * we could have is 1K.
94  * i.e. RXBUFFER_256 --> 960 byte skb (size-1024 slab)
95  * i.e. RXBUFFER_512 --> 1216 byte skb (size-2048 slab)
96  */
97 #define IAVF_RX_HDR_SIZE IAVF_RXBUFFER_256
98 #define IAVF_PACKET_HDR_PAD (ETH_HLEN + ETH_FCS_LEN + (VLAN_HLEN * 2))
99 #define iavf_rx_desc iavf_32byte_rx_desc
100 
101 #define IAVF_RX_DMA_ATTR \
102 	(DMA_ATTR_SKIP_CPU_SYNC | DMA_ATTR_WEAK_ORDERING)
103 
104 /* Attempt to maximize the headroom available for incoming frames.  We
105  * use a 2K buffer for receives and need 1536/1534 to store the data for
106  * the frame.  This leaves us with 512 bytes of room.  From that we need
107  * to deduct the space needed for the shared info and the padding needed
108  * to IP align the frame.
109  *
110  * Note: For cache line sizes 256 or larger this value is going to end
111  *	 up negative.  In these cases we should fall back to the legacy
112  *	 receive path.
113  */
114 #if (PAGE_SIZE < 8192)
115 #define IAVF_2K_TOO_SMALL_WITH_PADDING \
116 ((NET_SKB_PAD + IAVF_RXBUFFER_1536) > SKB_WITH_OVERHEAD(IAVF_RXBUFFER_2048))
117 
118 static inline int iavf_compute_pad(int rx_buf_len)
119 {
120 	int page_size, pad_size;
121 
122 	page_size = ALIGN(rx_buf_len, PAGE_SIZE / 2);
123 	pad_size = SKB_WITH_OVERHEAD(page_size) - rx_buf_len;
124 
125 	return pad_size;
126 }
127 
128 static inline int iavf_skb_pad(void)
129 {
130 	int rx_buf_len;
131 
132 	/* If a 2K buffer cannot handle a standard Ethernet frame then
133 	 * optimize padding for a 3K buffer instead of a 1.5K buffer.
134 	 *
135 	 * For a 3K buffer we need to add enough padding to allow for
136 	 * tailroom due to NET_IP_ALIGN possibly shifting us out of
137 	 * cache-line alignment.
138 	 */
139 	if (IAVF_2K_TOO_SMALL_WITH_PADDING)
140 		rx_buf_len = IAVF_RXBUFFER_3072 + SKB_DATA_ALIGN(NET_IP_ALIGN);
141 	else
142 		rx_buf_len = IAVF_RXBUFFER_1536;
143 
144 	/* if needed make room for NET_IP_ALIGN */
145 	rx_buf_len -= NET_IP_ALIGN;
146 
147 	return iavf_compute_pad(rx_buf_len);
148 }
149 
150 #define IAVF_SKB_PAD iavf_skb_pad()
151 #else
152 #define IAVF_2K_TOO_SMALL_WITH_PADDING false
153 #define IAVF_SKB_PAD (NET_SKB_PAD + NET_IP_ALIGN)
154 #endif
155 
156 /**
157  * iavf_test_staterr - tests bits in Rx descriptor status and error fields
158  * @rx_desc: pointer to receive descriptor (in le64 format)
159  * @stat_err_bits: value to mask
160  *
161  * This function does some fast chicanery in order to return the
162  * value of the mask which is really only used for boolean tests.
163  * The status_error_len doesn't need to be shifted because it begins
164  * at offset zero.
165  */
166 static inline bool iavf_test_staterr(union iavf_rx_desc *rx_desc,
167 				     const u64 stat_err_bits)
168 {
169 	return !!(rx_desc->wb.qword1.status_error_len &
170 		  cpu_to_le64(stat_err_bits));
171 }
172 
173 /* How many Rx Buffers do we bundle into one write to the hardware ? */
174 #define IAVF_RX_INCREMENT(r, i) \
175 	do {					\
176 		(i)++;				\
177 		if ((i) == (r)->count)		\
178 			i = 0;			\
179 		r->next_to_clean = i;		\
180 	} while (0)
181 
182 #define IAVF_RX_NEXT_DESC(r, i, n)		\
183 	do {					\
184 		(i)++;				\
185 		if ((i) == (r)->count)		\
186 			i = 0;			\
187 		(n) = IAVF_RX_DESC((r), (i));	\
188 	} while (0)
189 
190 #define IAVF_RX_NEXT_DESC_PREFETCH(r, i, n)		\
191 	do {						\
192 		IAVF_RX_NEXT_DESC((r), (i), (n));	\
193 		prefetch((n));				\
194 	} while (0)
195 
196 #define IAVF_MAX_BUFFER_TXD	8
197 #define IAVF_MIN_TX_LEN		17
198 
199 /* The size limit for a transmit buffer in a descriptor is (16K - 1).
200  * In order to align with the read requests we will align the value to
201  * the nearest 4K which represents our maximum read request size.
202  */
203 #define IAVF_MAX_READ_REQ_SIZE		4096
204 #define IAVF_MAX_DATA_PER_TXD		(16 * 1024 - 1)
205 #define IAVF_MAX_DATA_PER_TXD_ALIGNED \
206 	(IAVF_MAX_DATA_PER_TXD & ~(IAVF_MAX_READ_REQ_SIZE - 1))
207 
208 /**
209  * iavf_txd_use_count  - estimate the number of descriptors needed for Tx
210  * @size: transmit request size in bytes
211  *
212  * Due to hardware alignment restrictions (4K alignment), we need to
213  * assume that we can have no more than 12K of data per descriptor, even
214  * though each descriptor can take up to 16K - 1 bytes of aligned memory.
215  * Thus, we need to divide by 12K. But division is slow! Instead,
216  * we decompose the operation into shifts and one relatively cheap
217  * multiply operation.
218  *
219  * To divide by 12K, we first divide by 4K, then divide by 3:
220  *     To divide by 4K, shift right by 12 bits
221  *     To divide by 3, multiply by 85, then divide by 256
222  *     (Divide by 256 is done by shifting right by 8 bits)
223  * Finally, we add one to round up. Because 256 isn't an exact multiple of
224  * 3, we'll underestimate near each multiple of 12K. This is actually more
225  * accurate as we have 4K - 1 of wiggle room that we can fit into the last
226  * segment.  For our purposes this is accurate out to 1M which is orders of
227  * magnitude greater than our largest possible GSO size.
228  *
229  * This would then be implemented as:
230  *     return (((size >> 12) * 85) >> 8) + 1;
231  *
232  * Since multiplication and division are commutative, we can reorder
233  * operations into:
234  *     return ((size * 85) >> 20) + 1;
235  */
236 static inline unsigned int iavf_txd_use_count(unsigned int size)
237 {
238 	return ((size * 85) >> 20) + 1;
239 }
240 
241 /* Tx Descriptors needed, worst case */
242 #define DESC_NEEDED (MAX_SKB_FRAGS + 6)
243 #define IAVF_MIN_DESC_PENDING	4
244 
245 #define IAVF_TX_FLAGS_HW_VLAN			BIT(1)
246 #define IAVF_TX_FLAGS_SW_VLAN			BIT(2)
247 #define IAVF_TX_FLAGS_TSO			BIT(3)
248 #define IAVF_TX_FLAGS_IPV4			BIT(4)
249 #define IAVF_TX_FLAGS_IPV6			BIT(5)
250 #define IAVF_TX_FLAGS_FCCRC			BIT(6)
251 #define IAVF_TX_FLAGS_FSO			BIT(7)
252 #define IAVF_TX_FLAGS_FD_SB			BIT(9)
253 #define IAVF_TX_FLAGS_VXLAN_TUNNEL		BIT(10)
254 #define IAVF_TX_FLAGS_HW_OUTER_SINGLE_VLAN	BIT(11)
255 #define IAVF_TX_FLAGS_VLAN_MASK			0xffff0000
256 #define IAVF_TX_FLAGS_VLAN_PRIO_MASK		0xe0000000
257 #define IAVF_TX_FLAGS_VLAN_PRIO_SHIFT		29
258 #define IAVF_TX_FLAGS_VLAN_SHIFT		16
259 
260 struct iavf_tx_buffer {
261 	struct iavf_tx_desc *next_to_watch;
262 	union {
263 		struct sk_buff *skb;
264 		void *raw_buf;
265 	};
266 	unsigned int bytecount;
267 	unsigned short gso_segs;
268 
269 	DEFINE_DMA_UNMAP_ADDR(dma);
270 	DEFINE_DMA_UNMAP_LEN(len);
271 	u32 tx_flags;
272 };
273 
274 struct iavf_rx_buffer {
275 	dma_addr_t dma;
276 	struct page *page;
277 #if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536)
278 	__u32 page_offset;
279 #else
280 	__u16 page_offset;
281 #endif
282 	__u16 pagecnt_bias;
283 };
284 
285 struct iavf_queue_stats {
286 	u64 packets;
287 	u64 bytes;
288 };
289 
290 struct iavf_tx_queue_stats {
291 	u64 restart_queue;
292 	u64 tx_busy;
293 	u64 tx_done_old;
294 	u64 tx_linearize;
295 	u64 tx_force_wb;
296 	int prev_pkt_ctr;
297 	u64 tx_lost_interrupt;
298 };
299 
300 struct iavf_rx_queue_stats {
301 	u64 non_eop_descs;
302 	u64 alloc_page_failed;
303 	u64 alloc_buff_failed;
304 	u64 page_reuse_count;
305 	u64 realloc_count;
306 };
307 
308 enum iavf_ring_state_t {
309 	__IAVF_TX_FDIR_INIT_DONE,
310 	__IAVF_TX_XPS_INIT_DONE,
311 	__IAVF_RING_STATE_NBITS /* must be last */
312 };
313 
314 /* some useful defines for virtchannel interface, which
315  * is the only remaining user of header split
316  */
317 #define IAVF_RX_DTYPE_NO_SPLIT      0
318 #define IAVF_RX_DTYPE_HEADER_SPLIT  1
319 #define IAVF_RX_DTYPE_SPLIT_ALWAYS  2
320 #define IAVF_RX_SPLIT_L2      0x1
321 #define IAVF_RX_SPLIT_IP      0x2
322 #define IAVF_RX_SPLIT_TCP_UDP 0x4
323 #define IAVF_RX_SPLIT_SCTP    0x8
324 
325 /* struct that defines a descriptor ring, associated with a VSI */
326 struct iavf_ring {
327 	struct iavf_ring *next;		/* pointer to next ring in q_vector */
328 	void *desc;			/* Descriptor ring memory */
329 	struct device *dev;		/* Used for DMA mapping */
330 	struct net_device *netdev;	/* netdev ring maps to */
331 	union {
332 		struct iavf_tx_buffer *tx_bi;
333 		struct iavf_rx_buffer *rx_bi;
334 	};
335 	DECLARE_BITMAP(state, __IAVF_RING_STATE_NBITS);
336 	u16 queue_index;		/* Queue number of ring */
337 	u8 dcb_tc;			/* Traffic class of ring */
338 	u8 __iomem *tail;
339 
340 	/* high bit set means dynamic, use accessors routines to read/write.
341 	 * hardware only supports 2us resolution for the ITR registers.
342 	 * these values always store the USER setting, and must be converted
343 	 * before programming to a register.
344 	 */
345 	u16 itr_setting;
346 
347 	u16 count;			/* Number of descriptors */
348 	u16 reg_idx;			/* HW register index of the ring */
349 	u16 rx_buf_len;
350 
351 	/* used in interrupt processing */
352 	u16 next_to_use;
353 	u16 next_to_clean;
354 
355 	u8 atr_sample_rate;
356 	u8 atr_count;
357 
358 	bool ring_active;		/* is ring online or not */
359 	bool arm_wb;		/* do something to arm write back */
360 	u8 packet_stride;
361 
362 	u16 flags;
363 #define IAVF_TXR_FLAGS_WB_ON_ITR		BIT(0)
364 #define IAVF_RXR_FLAGS_BUILD_SKB_ENABLED	BIT(1)
365 #define IAVF_TXRX_FLAGS_VLAN_TAG_LOC_L2TAG1	BIT(3)
366 #define IAVF_TXR_FLAGS_VLAN_TAG_LOC_L2TAG2	BIT(4)
367 #define IAVF_RXR_FLAGS_VLAN_TAG_LOC_L2TAG2_2	BIT(5)
368 
369 	/* stats structs */
370 	struct iavf_queue_stats	stats;
371 	struct u64_stats_sync syncp;
372 	union {
373 		struct iavf_tx_queue_stats tx_stats;
374 		struct iavf_rx_queue_stats rx_stats;
375 	};
376 
377 	unsigned int size;		/* length of descriptor ring in bytes */
378 	dma_addr_t dma;			/* physical address of ring */
379 
380 	struct iavf_vsi *vsi;		/* Backreference to associated VSI */
381 	struct iavf_q_vector *q_vector;	/* Backreference to associated vector */
382 
383 	struct rcu_head rcu;		/* to avoid race on free */
384 	u16 next_to_alloc;
385 	struct sk_buff *skb;		/* When iavf_clean_rx_ring_irq() must
386 					 * return before it sees the EOP for
387 					 * the current packet, we save that skb
388 					 * here and resume receiving this
389 					 * packet the next time
390 					 * iavf_clean_rx_ring_irq() is called
391 					 * for this ring.
392 					 */
393 } ____cacheline_internodealigned_in_smp;
394 
395 static inline bool ring_uses_build_skb(struct iavf_ring *ring)
396 {
397 	return !!(ring->flags & IAVF_RXR_FLAGS_BUILD_SKB_ENABLED);
398 }
399 
400 static inline void set_ring_build_skb_enabled(struct iavf_ring *ring)
401 {
402 	ring->flags |= IAVF_RXR_FLAGS_BUILD_SKB_ENABLED;
403 }
404 
405 static inline void clear_ring_build_skb_enabled(struct iavf_ring *ring)
406 {
407 	ring->flags &= ~IAVF_RXR_FLAGS_BUILD_SKB_ENABLED;
408 }
409 
410 #define IAVF_ITR_ADAPTIVE_MIN_INC	0x0002
411 #define IAVF_ITR_ADAPTIVE_MIN_USECS	0x0002
412 #define IAVF_ITR_ADAPTIVE_MAX_USECS	0x007e
413 #define IAVF_ITR_ADAPTIVE_LATENCY	0x8000
414 #define IAVF_ITR_ADAPTIVE_BULK		0x0000
415 #define ITR_IS_BULK(x) (!((x) & IAVF_ITR_ADAPTIVE_LATENCY))
416 
417 struct iavf_ring_container {
418 	struct iavf_ring *ring;		/* pointer to linked list of ring(s) */
419 	unsigned long next_update;	/* jiffies value of next update */
420 	unsigned int total_bytes;	/* total bytes processed this int */
421 	unsigned int total_packets;	/* total packets processed this int */
422 	u16 count;
423 	u16 target_itr;			/* target ITR setting for ring(s) */
424 	u16 current_itr;		/* current ITR setting for ring(s) */
425 };
426 
427 /* iterator for handling rings in ring container */
428 #define iavf_for_each_ring(pos, head) \
429 	for (pos = (head).ring; pos != NULL; pos = pos->next)
430 
431 static inline unsigned int iavf_rx_pg_order(struct iavf_ring *ring)
432 {
433 #if (PAGE_SIZE < 8192)
434 	if (ring->rx_buf_len > (PAGE_SIZE / 2))
435 		return 1;
436 #endif
437 	return 0;
438 }
439 
440 #define iavf_rx_pg_size(_ring) (PAGE_SIZE << iavf_rx_pg_order(_ring))
441 
442 bool iavf_alloc_rx_buffers(struct iavf_ring *rxr, u16 cleaned_count);
443 netdev_tx_t iavf_xmit_frame(struct sk_buff *skb, struct net_device *netdev);
444 int iavf_setup_tx_descriptors(struct iavf_ring *tx_ring);
445 int iavf_setup_rx_descriptors(struct iavf_ring *rx_ring);
446 void iavf_free_tx_resources(struct iavf_ring *tx_ring);
447 void iavf_free_rx_resources(struct iavf_ring *rx_ring);
448 int iavf_napi_poll(struct napi_struct *napi, int budget);
449 void iavf_detect_recover_hung(struct iavf_vsi *vsi);
450 int __iavf_maybe_stop_tx(struct iavf_ring *tx_ring, int size);
451 bool __iavf_chk_linearize(struct sk_buff *skb);
452 
453 /**
454  * iavf_xmit_descriptor_count - calculate number of Tx descriptors needed
455  * @skb:     send buffer
456  *
457  * Returns number of data descriptors needed for this skb. Returns 0 to indicate
458  * there is not enough descriptors available in this ring since we need at least
459  * one descriptor.
460  **/
461 static inline int iavf_xmit_descriptor_count(struct sk_buff *skb)
462 {
463 	const skb_frag_t *frag = &skb_shinfo(skb)->frags[0];
464 	unsigned int nr_frags = skb_shinfo(skb)->nr_frags;
465 	int count = 0, size = skb_headlen(skb);
466 
467 	for (;;) {
468 		count += iavf_txd_use_count(size);
469 
470 		if (!nr_frags--)
471 			break;
472 
473 		size = skb_frag_size(frag++);
474 	}
475 
476 	return count;
477 }
478 
479 /**
480  * iavf_maybe_stop_tx - 1st level check for Tx stop conditions
481  * @tx_ring: the ring to be checked
482  * @size:    the size buffer we want to assure is available
483  *
484  * Returns 0 if stop is not needed
485  **/
486 static inline int iavf_maybe_stop_tx(struct iavf_ring *tx_ring, int size)
487 {
488 	if (likely(IAVF_DESC_UNUSED(tx_ring) >= size))
489 		return 0;
490 	return __iavf_maybe_stop_tx(tx_ring, size);
491 }
492 
493 /**
494  * iavf_chk_linearize - Check if there are more than 8 fragments per packet
495  * @skb:      send buffer
496  * @count:    number of buffers used
497  *
498  * Note: Our HW can't scatter-gather more than 8 fragments to build
499  * a packet on the wire and so we need to figure out the cases where we
500  * need to linearize the skb.
501  **/
502 static inline bool iavf_chk_linearize(struct sk_buff *skb, int count)
503 {
504 	/* Both TSO and single send will work if count is less than 8 */
505 	if (likely(count < IAVF_MAX_BUFFER_TXD))
506 		return false;
507 
508 	if (skb_is_gso(skb))
509 		return __iavf_chk_linearize(skb);
510 
511 	/* we can support up to 8 data buffers for a single send */
512 	return count != IAVF_MAX_BUFFER_TXD;
513 }
514 /**
515  * txring_txq - helper to convert from a ring to a queue
516  * @ring: Tx ring to find the netdev equivalent of
517  **/
518 static inline struct netdev_queue *txring_txq(const struct iavf_ring *ring)
519 {
520 	return netdev_get_tx_queue(ring->netdev, ring->queue_index);
521 }
522 #endif /* _IAVF_TXRX_H_ */
523