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  1/* SPDX-License-Identifier: GPL-2.0 */
  2/*******************************************************************************
  3 *
  4 * Intel Ethernet Controller XL710 Family Linux Virtual Function Driver
  5 * Copyright(c) 2013 - 2016 Intel Corporation.
  6 *
  7 * This program is free software; you can redistribute it and/or modify it
  8 * under the terms and conditions of the GNU General Public License,
  9 * version 2, as published by the Free Software Foundation.
 10 *
 11 * This program is distributed in the hope it will be useful, but WITHOUT
 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 14 * more details.
 15 *
 16 * You should have received a copy of the GNU General Public License along
 17 * with this program.  If not, see <http://www.gnu.org/licenses/>.
 18 *
 19 * The full GNU General Public License is included in this distribution in
 20 * the file called "COPYING".
 21 *
 22 * Contact Information:
 23 * e1000-devel Mailing List <e1000-devel@lists.sourceforge.net>
 24 * Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
 25 *
 26 ******************************************************************************/
 27
 28#ifndef _I40E_TXRX_H_
 29#define _I40E_TXRX_H_
 30
 31/* Interrupt Throttling and Rate Limiting Goodies */
 32#define I40E_DEFAULT_IRQ_WORK      256
 33
 34/* The datasheet for the X710 and XL710 indicate that the maximum value for
 35 * the ITR is 8160usec which is then called out as 0xFF0 with a 2usec
 36 * resolution. 8160 is 0x1FE0 when written out in hex. So instead of storing
 37 * the register value which is divided by 2 lets use the actual values and
 38 * avoid an excessive amount of translation.
 39 */
 40#define I40E_ITR_DYNAMIC	0x8000	/* use top bit as a flag */
 41#define I40E_ITR_MASK		0x1FFE	/* mask for ITR register value */
 42#define I40E_MIN_ITR		     2	/* reg uses 2 usec resolution */
 43#define I40E_ITR_100K		    10	/* all values below must be even */
 44#define I40E_ITR_50K		    20
 45#define I40E_ITR_20K		    50
 46#define I40E_ITR_18K		    60
 47#define I40E_ITR_8K		   122
 48#define I40E_MAX_ITR		  8160	/* maximum value as per datasheet */
 49#define ITR_TO_REG(setting) ((setting) & ~I40E_ITR_DYNAMIC)
 50#define ITR_REG_ALIGN(setting) __ALIGN_MASK(setting, ~I40E_ITR_MASK)
 51#define ITR_IS_DYNAMIC(setting) (!!((setting) & I40E_ITR_DYNAMIC))
 52
 53#define I40E_ITR_RX_DEF		(I40E_ITR_20K | I40E_ITR_DYNAMIC)
 54#define I40E_ITR_TX_DEF		(I40E_ITR_20K | I40E_ITR_DYNAMIC)
 55
 56/* 0x40 is the enable bit for interrupt rate limiting, and must be set if
 57 * the value of the rate limit is non-zero
 58 */
 59#define INTRL_ENA                  BIT(6)
 60#define I40E_MAX_INTRL             0x3B    /* reg uses 4 usec resolution */
 61#define INTRL_REG_TO_USEC(intrl) ((intrl & ~INTRL_ENA) << 2)
 62#define INTRL_USEC_TO_REG(set) ((set) ? ((set) >> 2) | INTRL_ENA : 0)
 63#define I40E_INTRL_8K              125     /* 8000 ints/sec */
 64#define I40E_INTRL_62K             16      /* 62500 ints/sec */
 65#define I40E_INTRL_83K             12      /* 83333 ints/sec */
 66
 67#define I40E_QUEUE_END_OF_LIST 0x7FF
 68
 69/* this enum matches hardware bits and is meant to be used by DYN_CTLN
 70 * registers and QINT registers or more generally anywhere in the manual
 71 * mentioning ITR_INDX, ITR_NONE cannot be used as an index 'n' into any
 72 * register but instead is a special value meaning "don't update" ITR0/1/2.
 73 */
 74enum i40e_dyn_idx_t {
 75	I40E_IDX_ITR0 = 0,
 76	I40E_IDX_ITR1 = 1,
 77	I40E_IDX_ITR2 = 2,
 78	I40E_ITR_NONE = 3	/* ITR_NONE must not be used as an index */
 79};
 80
 81/* these are indexes into ITRN registers */
 82#define I40E_RX_ITR    I40E_IDX_ITR0
 83#define I40E_TX_ITR    I40E_IDX_ITR1
 84#define I40E_PE_ITR    I40E_IDX_ITR2
 85
 86/* Supported RSS offloads */
 87#define I40E_DEFAULT_RSS_HENA ( \
 88	BIT_ULL(I40E_FILTER_PCTYPE_NONF_IPV4_UDP) | \
 89	BIT_ULL(I40E_FILTER_PCTYPE_NONF_IPV4_SCTP) | \
 90	BIT_ULL(I40E_FILTER_PCTYPE_NONF_IPV4_TCP) | \
 91	BIT_ULL(I40E_FILTER_PCTYPE_NONF_IPV4_OTHER) | \
 92	BIT_ULL(I40E_FILTER_PCTYPE_FRAG_IPV4) | \
 93	BIT_ULL(I40E_FILTER_PCTYPE_NONF_IPV6_UDP) | \
 94	BIT_ULL(I40E_FILTER_PCTYPE_NONF_IPV6_TCP) | \
 95	BIT_ULL(I40E_FILTER_PCTYPE_NONF_IPV6_SCTP) | \
 96	BIT_ULL(I40E_FILTER_PCTYPE_NONF_IPV6_OTHER) | \
 97	BIT_ULL(I40E_FILTER_PCTYPE_FRAG_IPV6) | \
 98	BIT_ULL(I40E_FILTER_PCTYPE_L2_PAYLOAD))
 99
100#define I40E_DEFAULT_RSS_HENA_EXPANDED (I40E_DEFAULT_RSS_HENA | \
101	BIT_ULL(I40E_FILTER_PCTYPE_NONF_IPV4_TCP_SYN_NO_ACK) | \
102	BIT_ULL(I40E_FILTER_PCTYPE_NONF_UNICAST_IPV4_UDP) | \
103	BIT_ULL(I40E_FILTER_PCTYPE_NONF_MULTICAST_IPV4_UDP) | \
104	BIT_ULL(I40E_FILTER_PCTYPE_NONF_IPV6_TCP_SYN_NO_ACK) | \
105	BIT_ULL(I40E_FILTER_PCTYPE_NONF_UNICAST_IPV6_UDP) | \
106	BIT_ULL(I40E_FILTER_PCTYPE_NONF_MULTICAST_IPV6_UDP))
107
108/* Supported Rx Buffer Sizes (a multiple of 128) */
109#define I40E_RXBUFFER_256   256
110#define I40E_RXBUFFER_1536  1536  /* 128B aligned standard Ethernet frame */
111#define I40E_RXBUFFER_2048  2048
112#define I40E_RXBUFFER_3072  3072  /* Used for large frames w/ padding */
113#define I40E_MAX_RXBUFFER   9728  /* largest size for single descriptor */
114
115/* NOTE: netdev_alloc_skb reserves up to 64 bytes, NET_IP_ALIGN means we
116 * reserve 2 more, and skb_shared_info adds an additional 384 bytes more,
117 * this adds up to 512 bytes of extra data meaning the smallest allocation
118 * we could have is 1K.
119 * i.e. RXBUFFER_256 --> 960 byte skb (size-1024 slab)
120 * i.e. RXBUFFER_512 --> 1216 byte skb (size-2048 slab)
121 */
122#define I40E_RX_HDR_SIZE I40E_RXBUFFER_256
123#define I40E_PACKET_HDR_PAD (ETH_HLEN + ETH_FCS_LEN + (VLAN_HLEN * 2))
124#define i40e_rx_desc i40e_32byte_rx_desc
125
126#define I40E_RX_DMA_ATTR \
127	(DMA_ATTR_SKIP_CPU_SYNC | DMA_ATTR_WEAK_ORDERING)
128
129/* Attempt to maximize the headroom available for incoming frames.  We
130 * use a 2K buffer for receives and need 1536/1534 to store the data for
131 * the frame.  This leaves us with 512 bytes of room.  From that we need
132 * to deduct the space needed for the shared info and the padding needed
133 * to IP align the frame.
134 *
135 * Note: For cache line sizes 256 or larger this value is going to end
136 *	 up negative.  In these cases we should fall back to the legacy
137 *	 receive path.
138 */
139#if (PAGE_SIZE < 8192)
140#define I40E_2K_TOO_SMALL_WITH_PADDING \
141((NET_SKB_PAD + I40E_RXBUFFER_1536) > SKB_WITH_OVERHEAD(I40E_RXBUFFER_2048))
142
143static inline int i40e_compute_pad(int rx_buf_len)
144{
145	int page_size, pad_size;
146
147	page_size = ALIGN(rx_buf_len, PAGE_SIZE / 2);
148	pad_size = SKB_WITH_OVERHEAD(page_size) - rx_buf_len;
149
150	return pad_size;
151}
152
153static inline int i40e_skb_pad(void)
154{
155	int rx_buf_len;
156
157	/* If a 2K buffer cannot handle a standard Ethernet frame then
158	 * optimize padding for a 3K buffer instead of a 1.5K buffer.
159	 *
160	 * For a 3K buffer we need to add enough padding to allow for
161	 * tailroom due to NET_IP_ALIGN possibly shifting us out of
162	 * cache-line alignment.
163	 */
164	if (I40E_2K_TOO_SMALL_WITH_PADDING)
165		rx_buf_len = I40E_RXBUFFER_3072 + SKB_DATA_ALIGN(NET_IP_ALIGN);
166	else
167		rx_buf_len = I40E_RXBUFFER_1536;
168
169	/* if needed make room for NET_IP_ALIGN */
170	rx_buf_len -= NET_IP_ALIGN;
171
172	return i40e_compute_pad(rx_buf_len);
173}
174
175#define I40E_SKB_PAD i40e_skb_pad()
176#else
177#define I40E_2K_TOO_SMALL_WITH_PADDING false
178#define I40E_SKB_PAD (NET_SKB_PAD + NET_IP_ALIGN)
179#endif
180
181/**
182 * i40e_test_staterr - tests bits in Rx descriptor status and error fields
183 * @rx_desc: pointer to receive descriptor (in le64 format)
184 * @stat_err_bits: value to mask
185 *
186 * This function does some fast chicanery in order to return the
187 * value of the mask which is really only used for boolean tests.
188 * The status_error_len doesn't need to be shifted because it begins
189 * at offset zero.
190 */
191static inline bool i40e_test_staterr(union i40e_rx_desc *rx_desc,
192				     const u64 stat_err_bits)
193{
194	return !!(rx_desc->wb.qword1.status_error_len &
195		  cpu_to_le64(stat_err_bits));
196}
197
198/* How many Rx Buffers do we bundle into one write to the hardware ? */
199#define I40E_RX_BUFFER_WRITE	32	/* Must be power of 2 */
200#define I40E_RX_INCREMENT(r, i) \
201	do {					\
202		(i)++;				\
203		if ((i) == (r)->count)		\
204			i = 0;			\
205		r->next_to_clean = i;		\
206	} while (0)
207
208#define I40E_RX_NEXT_DESC(r, i, n)		\
209	do {					\
210		(i)++;				\
211		if ((i) == (r)->count)		\
212			i = 0;			\
213		(n) = I40E_RX_DESC((r), (i));	\
214	} while (0)
215
216#define I40E_RX_NEXT_DESC_PREFETCH(r, i, n)		\
217	do {						\
218		I40E_RX_NEXT_DESC((r), (i), (n));	\
219		prefetch((n));				\
220	} while (0)
221
222#define I40E_MAX_BUFFER_TXD	8
223#define I40E_MIN_TX_LEN		17
224
225/* The size limit for a transmit buffer in a descriptor is (16K - 1).
226 * In order to align with the read requests we will align the value to
227 * the nearest 4K which represents our maximum read request size.
228 */
229#define I40E_MAX_READ_REQ_SIZE		4096
230#define I40E_MAX_DATA_PER_TXD		(16 * 1024 - 1)
231#define I40E_MAX_DATA_PER_TXD_ALIGNED \
232	(I40E_MAX_DATA_PER_TXD & ~(I40E_MAX_READ_REQ_SIZE - 1))
233
234/**
235 * i40e_txd_use_count  - estimate the number of descriptors needed for Tx
236 * @size: transmit request size in bytes
237 *
238 * Due to hardware alignment restrictions (4K alignment), we need to
239 * assume that we can have no more than 12K of data per descriptor, even
240 * though each descriptor can take up to 16K - 1 bytes of aligned memory.
241 * Thus, we need to divide by 12K. But division is slow! Instead,
242 * we decompose the operation into shifts and one relatively cheap
243 * multiply operation.
244 *
245 * To divide by 12K, we first divide by 4K, then divide by 3:
246 *     To divide by 4K, shift right by 12 bits
247 *     To divide by 3, multiply by 85, then divide by 256
248 *     (Divide by 256 is done by shifting right by 8 bits)
249 * Finally, we add one to round up. Because 256 isn't an exact multiple of
250 * 3, we'll underestimate near each multiple of 12K. This is actually more
251 * accurate as we have 4K - 1 of wiggle room that we can fit into the last
252 * segment.  For our purposes this is accurate out to 1M which is orders of
253 * magnitude greater than our largest possible GSO size.
254 *
255 * This would then be implemented as:
256 *     return (((size >> 12) * 85) >> 8) + 1;
257 *
258 * Since multiplication and division are commutative, we can reorder
259 * operations into:
260 *     return ((size * 85) >> 20) + 1;
261 */
262static inline unsigned int i40e_txd_use_count(unsigned int size)
263{
264	return ((size * 85) >> 20) + 1;
265}
266
267/* Tx Descriptors needed, worst case */
268#define DESC_NEEDED (MAX_SKB_FRAGS + 6)
269#define I40E_MIN_DESC_PENDING	4
270
271#define I40E_TX_FLAGS_HW_VLAN		BIT(1)
272#define I40E_TX_FLAGS_SW_VLAN		BIT(2)
273#define I40E_TX_FLAGS_TSO		BIT(3)
274#define I40E_TX_FLAGS_IPV4		BIT(4)
275#define I40E_TX_FLAGS_IPV6		BIT(5)
276#define I40E_TX_FLAGS_FCCRC		BIT(6)
277#define I40E_TX_FLAGS_FSO		BIT(7)
278#define I40E_TX_FLAGS_FD_SB		BIT(9)
279#define I40E_TX_FLAGS_VXLAN_TUNNEL	BIT(10)
280#define I40E_TX_FLAGS_VLAN_MASK		0xffff0000
281#define I40E_TX_FLAGS_VLAN_PRIO_MASK	0xe0000000
282#define I40E_TX_FLAGS_VLAN_PRIO_SHIFT	29
283#define I40E_TX_FLAGS_VLAN_SHIFT	16
284
285struct i40e_tx_buffer {
286	struct i40e_tx_desc *next_to_watch;
287	union {
288		struct sk_buff *skb;
289		void *raw_buf;
290	};
291	unsigned int bytecount;
292	unsigned short gso_segs;
293
294	DEFINE_DMA_UNMAP_ADDR(dma);
295	DEFINE_DMA_UNMAP_LEN(len);
296	u32 tx_flags;
297};
298
299struct i40e_rx_buffer {
300	dma_addr_t dma;
301	struct page *page;
302#if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536)
303	__u32 page_offset;
304#else
305	__u16 page_offset;
306#endif
307	__u16 pagecnt_bias;
308};
309
310struct i40e_queue_stats {
311	u64 packets;
312	u64 bytes;
313};
314
315struct i40e_tx_queue_stats {
316	u64 restart_queue;
317	u64 tx_busy;
318	u64 tx_done_old;
319	u64 tx_linearize;
320	u64 tx_force_wb;
321	int prev_pkt_ctr;
322	u64 tx_lost_interrupt;
323};
324
325struct i40e_rx_queue_stats {
326	u64 non_eop_descs;
327	u64 alloc_page_failed;
328	u64 alloc_buff_failed;
329	u64 page_reuse_count;
330	u64 realloc_count;
331};
332
333enum i40e_ring_state_t {
334	__I40E_TX_FDIR_INIT_DONE,
335	__I40E_TX_XPS_INIT_DONE,
336	__I40E_RING_STATE_NBITS /* must be last */
337};
338
339/* some useful defines for virtchannel interface, which
340 * is the only remaining user of header split
341 */
342#define I40E_RX_DTYPE_NO_SPLIT      0
343#define I40E_RX_DTYPE_HEADER_SPLIT  1
344#define I40E_RX_DTYPE_SPLIT_ALWAYS  2
345#define I40E_RX_SPLIT_L2      0x1
346#define I40E_RX_SPLIT_IP      0x2
347#define I40E_RX_SPLIT_TCP_UDP 0x4
348#define I40E_RX_SPLIT_SCTP    0x8
349
350/* struct that defines a descriptor ring, associated with a VSI */
351struct i40e_ring {
352	struct i40e_ring *next;		/* pointer to next ring in q_vector */
353	void *desc;			/* Descriptor ring memory */
354	struct device *dev;		/* Used for DMA mapping */
355	struct net_device *netdev;	/* netdev ring maps to */
356	union {
357		struct i40e_tx_buffer *tx_bi;
358		struct i40e_rx_buffer *rx_bi;
359	};
360	DECLARE_BITMAP(state, __I40E_RING_STATE_NBITS);
361	u16 queue_index;		/* Queue number of ring */
362	u8 dcb_tc;			/* Traffic class of ring */
363	u8 __iomem *tail;
364
365	/* high bit set means dynamic, use accessors routines to read/write.
366	 * hardware only supports 2us resolution for the ITR registers.
367	 * these values always store the USER setting, and must be converted
368	 * before programming to a register.
369	 */
370	u16 itr_setting;
371
372	u16 count;			/* Number of descriptors */
373	u16 reg_idx;			/* HW register index of the ring */
374	u16 rx_buf_len;
375
376	/* used in interrupt processing */
377	u16 next_to_use;
378	u16 next_to_clean;
379
380	u8 atr_sample_rate;
381	u8 atr_count;
382
383	bool ring_active;		/* is ring online or not */
384	bool arm_wb;		/* do something to arm write back */
385	u8 packet_stride;
386
387	u16 flags;
388#define I40E_TXR_FLAGS_WB_ON_ITR		BIT(0)
389#define I40E_RXR_FLAGS_BUILD_SKB_ENABLED	BIT(1)
390
391	/* stats structs */
392	struct i40e_queue_stats	stats;
393	struct u64_stats_sync syncp;
394	union {
395		struct i40e_tx_queue_stats tx_stats;
396		struct i40e_rx_queue_stats rx_stats;
397	};
398
399	unsigned int size;		/* length of descriptor ring in bytes */
400	dma_addr_t dma;			/* physical address of ring */
401
402	struct i40e_vsi *vsi;		/* Backreference to associated VSI */
403	struct i40e_q_vector *q_vector;	/* Backreference to associated vector */
404
405	struct rcu_head rcu;		/* to avoid race on free */
406	u16 next_to_alloc;
407	struct sk_buff *skb;		/* When i40evf_clean_rx_ring_irq() must
408					 * return before it sees the EOP for
409					 * the current packet, we save that skb
410					 * here and resume receiving this
411					 * packet the next time
412					 * i40evf_clean_rx_ring_irq() is called
413					 * for this ring.
414					 */
415} ____cacheline_internodealigned_in_smp;
416
417static inline bool ring_uses_build_skb(struct i40e_ring *ring)
418{
419	return !!(ring->flags & I40E_RXR_FLAGS_BUILD_SKB_ENABLED);
420}
421
422static inline void set_ring_build_skb_enabled(struct i40e_ring *ring)
423{
424	ring->flags |= I40E_RXR_FLAGS_BUILD_SKB_ENABLED;
425}
426
427static inline void clear_ring_build_skb_enabled(struct i40e_ring *ring)
428{
429	ring->flags &= ~I40E_RXR_FLAGS_BUILD_SKB_ENABLED;
430}
431
432#define I40E_ITR_ADAPTIVE_MIN_INC	0x0002
433#define I40E_ITR_ADAPTIVE_MIN_USECS	0x0002
434#define I40E_ITR_ADAPTIVE_MAX_USECS	0x007e
435#define I40E_ITR_ADAPTIVE_LATENCY	0x8000
436#define I40E_ITR_ADAPTIVE_BULK		0x0000
437#define ITR_IS_BULK(x) (!((x) & I40E_ITR_ADAPTIVE_LATENCY))
438
439struct i40e_ring_container {
440	struct i40e_ring *ring;		/* pointer to linked list of ring(s) */
441	unsigned long next_update;	/* jiffies value of next update */
442	unsigned int total_bytes;	/* total bytes processed this int */
443	unsigned int total_packets;	/* total packets processed this int */
444	u16 count;
445	u16 target_itr;			/* target ITR setting for ring(s) */
446	u16 current_itr;		/* current ITR setting for ring(s) */
447};
448
449/* iterator for handling rings in ring container */
450#define i40e_for_each_ring(pos, head) \
451	for (pos = (head).ring; pos != NULL; pos = pos->next)
452
453static inline unsigned int i40e_rx_pg_order(struct i40e_ring *ring)
454{
455#if (PAGE_SIZE < 8192)
456	if (ring->rx_buf_len > (PAGE_SIZE / 2))
457		return 1;
458#endif
459	return 0;
460}
461
462#define i40e_rx_pg_size(_ring) (PAGE_SIZE << i40e_rx_pg_order(_ring))
463
464bool i40evf_alloc_rx_buffers(struct i40e_ring *rxr, u16 cleaned_count);
465netdev_tx_t i40evf_xmit_frame(struct sk_buff *skb, struct net_device *netdev);
466void i40evf_clean_tx_ring(struct i40e_ring *tx_ring);
467void i40evf_clean_rx_ring(struct i40e_ring *rx_ring);
468int i40evf_setup_tx_descriptors(struct i40e_ring *tx_ring);
469int i40evf_setup_rx_descriptors(struct i40e_ring *rx_ring);
470void i40evf_free_tx_resources(struct i40e_ring *tx_ring);
471void i40evf_free_rx_resources(struct i40e_ring *rx_ring);
472int i40evf_napi_poll(struct napi_struct *napi, int budget);
473void i40evf_force_wb(struct i40e_vsi *vsi, struct i40e_q_vector *q_vector);
474u32 i40evf_get_tx_pending(struct i40e_ring *ring, bool in_sw);
475void i40evf_detect_recover_hung(struct i40e_vsi *vsi);
476int __i40evf_maybe_stop_tx(struct i40e_ring *tx_ring, int size);
477bool __i40evf_chk_linearize(struct sk_buff *skb);
478
479/**
480 * i40e_xmit_descriptor_count - calculate number of Tx descriptors needed
481 * @skb:     send buffer
482 * @tx_ring: ring to send buffer on
483 *
484 * Returns number of data descriptors needed for this skb. Returns 0 to indicate
485 * there is not enough descriptors available in this ring since we need at least
486 * one descriptor.
487 **/
488static inline int i40e_xmit_descriptor_count(struct sk_buff *skb)
489{
490	const struct skb_frag_struct *frag = &skb_shinfo(skb)->frags[0];
491	unsigned int nr_frags = skb_shinfo(skb)->nr_frags;
492	int count = 0, size = skb_headlen(skb);
493
494	for (;;) {
495		count += i40e_txd_use_count(size);
496
497		if (!nr_frags--)
498			break;
499
500		size = skb_frag_size(frag++);
501	}
502
503	return count;
504}
505
506/**
507 * i40e_maybe_stop_tx - 1st level check for Tx stop conditions
508 * @tx_ring: the ring to be checked
509 * @size:    the size buffer we want to assure is available
510 *
511 * Returns 0 if stop is not needed
512 **/
513static inline int i40e_maybe_stop_tx(struct i40e_ring *tx_ring, int size)
514{
515	if (likely(I40E_DESC_UNUSED(tx_ring) >= size))
516		return 0;
517	return __i40evf_maybe_stop_tx(tx_ring, size);
518}
519
520/**
521 * i40e_chk_linearize - Check if there are more than 8 fragments per packet
522 * @skb:      send buffer
523 * @count:    number of buffers used
524 *
525 * Note: Our HW can't scatter-gather more than 8 fragments to build
526 * a packet on the wire and so we need to figure out the cases where we
527 * need to linearize the skb.
528 **/
529static inline bool i40e_chk_linearize(struct sk_buff *skb, int count)
530{
531	/* Both TSO and single send will work if count is less than 8 */
532	if (likely(count < I40E_MAX_BUFFER_TXD))
533		return false;
534
535	if (skb_is_gso(skb))
536		return __i40evf_chk_linearize(skb);
537
538	/* we can support up to 8 data buffers for a single send */
539	return count != I40E_MAX_BUFFER_TXD;
540}
541/**
542 * @ring: Tx ring to find the netdev equivalent of
543 **/
544static inline struct netdev_queue *txring_txq(const struct i40e_ring *ring)
545{
546	return netdev_get_tx_queue(ring->netdev, ring->queue_index);
547}
548#endif /* _I40E_TXRX_H_ */