1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_NET_QUEUES_H
3 #define _LINUX_NET_QUEUES_H
4
5 #include <linux/netdevice.h>
6
7 /**
8 * struct netdev_config - queue-related configuration for a netdev
9 * @hds_thresh: HDS Threshold value.
10 * @hds_config: HDS value from userspace.
11 */
12 struct netdev_config {
13 u32 hds_thresh;
14 u8 hds_config;
15 };
16
17 struct netdev_queue_config {
18 u32 rx_page_size;
19 };
20
21 /* See the netdev.yaml spec for definition of each statistic */
22 struct netdev_queue_stats_rx {
23 u64 bytes;
24 u64 packets;
25 u64 alloc_fail;
26
27 u64 hw_drops;
28 u64 hw_drop_overruns;
29
30 u64 csum_complete;
31 u64 csum_unnecessary;
32 u64 csum_none;
33 u64 csum_bad;
34
35 u64 hw_gro_packets;
36 u64 hw_gro_bytes;
37 u64 hw_gro_wire_packets;
38 u64 hw_gro_wire_bytes;
39
40 u64 hw_drop_ratelimits;
41 };
42
43 struct netdev_queue_stats_tx {
44 u64 bytes;
45 u64 packets;
46
47 u64 hw_drops;
48 u64 hw_drop_errors;
49
50 u64 csum_none;
51 u64 needs_csum;
52
53 u64 hw_gso_packets;
54 u64 hw_gso_bytes;
55 u64 hw_gso_wire_packets;
56 u64 hw_gso_wire_bytes;
57
58 u64 hw_drop_ratelimits;
59
60 u64 stop;
61 u64 wake;
62 };
63
64 /**
65 * struct netdev_stat_ops - netdev ops for fine grained stats
66 * @get_queue_stats_rx: get stats for a given Rx queue
67 * @get_queue_stats_tx: get stats for a given Tx queue
68 * @get_base_stats: get base stats (not belonging to any live instance)
69 *
70 * Query stats for a given object. The values of the statistics are undefined
71 * on entry (specifically they are *not* zero-initialized). Drivers should
72 * assign values only to the statistics they collect. Statistics which are not
73 * collected must be left undefined.
74 *
75 * Queue objects are not necessarily persistent, and only currently active
76 * queues are queried by the per-queue callbacks. This means that per-queue
77 * statistics will not generally add up to the total number of events for
78 * the device. The @get_base_stats callback allows filling in the delta
79 * between events for currently live queues and overall device history.
80 * @get_base_stats can also be used to report any miscellaneous packets
81 * transferred outside of the main set of queues used by the networking stack.
82 * When the statistics for the entire device are queried, first @get_base_stats
83 * is issued to collect the delta, and then a series of per-queue callbacks.
84 * Only statistics which are set in @get_base_stats will be reported
85 * at the device level, meaning that unlike in queue callbacks, setting
86 * a statistic to zero in @get_base_stats is a legitimate thing to do.
87 * This is because @get_base_stats has a second function of designating which
88 * statistics are in fact correct for the entire device (e.g. when history
89 * for some of the events is not maintained, and reliable "total" cannot
90 * be provided).
91 *
92 * Ops are called under the instance lock if netdev_need_ops_lock()
93 * returns true, otherwise under rtnl_lock.
94 * Device drivers can assume that when collecting total device stats,
95 * the @get_base_stats and subsequent per-queue calls are performed
96 * "atomically" (without releasing the relevant lock).
97 *
98 * Device drivers are encouraged to reset the per-queue statistics when
99 * number of queues change. This is because the primary use case for
100 * per-queue statistics is currently to detect traffic imbalance.
101 */
102 struct netdev_stat_ops {
103 void (*get_queue_stats_rx)(struct net_device *dev, int idx,
104 struct netdev_queue_stats_rx *stats);
105 void (*get_queue_stats_tx)(struct net_device *dev, int idx,
106 struct netdev_queue_stats_tx *stats);
107 void (*get_base_stats)(struct net_device *dev,
108 struct netdev_queue_stats_rx *rx,
109 struct netdev_queue_stats_tx *tx);
110 };
111
112 void netdev_stat_queue_sum(struct net_device *netdev,
113 int rx_start, int rx_end,
114 struct netdev_queue_stats_rx *rx_sum,
115 int tx_start, int tx_end,
116 struct netdev_queue_stats_tx *tx_sum);
117
118 enum {
119 /* The queue checks and honours the page size qcfg parameter */
120 QCFG_RX_PAGE_SIZE = 0x1,
121 };
122
123 /**
124 * struct netdev_queue_mgmt_ops - netdev ops for queue management
125 *
126 * @ndo_queue_mem_size: Size of the struct that describes a queue's memory.
127 *
128 * @ndo_queue_mem_alloc: Allocate memory for an RX queue at the specified index.
129 * The new memory is written at the specified address.
130 *
131 * @ndo_queue_mem_free: Free memory from an RX queue.
132 *
133 * @ndo_queue_start: Start an RX queue with the specified memory and at the
134 * specified index.
135 *
136 * @ndo_queue_stop: Stop the RX queue at the specified index. The stopped
137 * queue's memory is written at the specified address.
138 *
139 * @ndo_queue_get_dma_dev: Get dma device for zero-copy operations to be used
140 * for this queue. Return NULL on error.
141 *
142 * @ndo_default_qcfg: (Optional) Populate queue config struct with defaults.
143 * Queue config structs are passed to this helper before
144 * the user-requested settings are applied.
145 *
146 * @ndo_validate_qcfg: (Optional) Check if queue config is supported.
147 * Called when configuration affecting a queue may be
148 * changing, either due to NIC-wide config, or config
149 * scoped to the queue at a specified index.
150 * When NIC-wide config is changed the callback will
151 * be invoked for all queues.
152 *
153 * @supported_params: Bitmask of supported parameters, see QCFG_*.
154 *
155 * Note that @ndo_queue_mem_alloc and @ndo_queue_mem_free may be called while
156 * the interface is closed. @ndo_queue_start and @ndo_queue_stop will only
157 * be called for an interface which is open.
158 */
159 struct netdev_queue_mgmt_ops {
160 size_t ndo_queue_mem_size;
161 int (*ndo_queue_mem_alloc)(struct net_device *dev,
162 struct netdev_queue_config *qcfg,
163 void *per_queue_mem,
164 int idx);
165 void (*ndo_queue_mem_free)(struct net_device *dev,
166 void *per_queue_mem);
167 int (*ndo_queue_start)(struct net_device *dev,
168 struct netdev_queue_config *qcfg,
169 void *per_queue_mem,
170 int idx);
171 int (*ndo_queue_stop)(struct net_device *dev,
172 void *per_queue_mem,
173 int idx);
174 void (*ndo_default_qcfg)(struct net_device *dev,
175 struct netdev_queue_config *qcfg);
176 int (*ndo_validate_qcfg)(struct net_device *dev,
177 struct netdev_queue_config *qcfg,
178 struct netlink_ext_ack *extack);
179 struct device * (*ndo_queue_get_dma_dev)(struct net_device *dev,
180 int idx);
181
182 unsigned int supported_params;
183 };
184
185 void netdev_queue_config(struct net_device *dev, int rxq,
186 struct netdev_queue_config *qcfg);
187
188 bool netif_rxq_has_unreadable_mp(struct net_device *dev, int idx);
189
190 /**
191 * DOC: Lockless queue stopping / waking helpers.
192 *
193 * The netif_txq_maybe_stop() and __netif_txq_completed_wake()
194 * macros are designed to safely implement stopping
195 * and waking netdev queues without full lock protection.
196 *
197 * We assume that there can be no concurrent stop attempts and no concurrent
198 * wake attempts. The try-stop should happen from the xmit handler,
199 * while wake up should be triggered from NAPI poll context.
200 * The two may run concurrently (single producer, single consumer).
201 *
202 * The try-stop side is expected to run from the xmit handler and therefore
203 * it does not reschedule Tx (netif_tx_start_queue() instead of
204 * netif_tx_wake_queue()). Uses of the ``stop`` macros outside of the xmit
205 * handler may lead to xmit queue being enabled but not run.
206 * The waking side does not have similar context restrictions.
207 *
208 * The macros guarantee that rings will not remain stopped if there's
209 * space available, but they do *not* prevent false wake ups when
210 * the ring is full! Drivers should check for ring full at the start
211 * for the xmit handler.
212 *
213 * All descriptor ring indexes (and other relevant shared state) must
214 * be updated before invoking the macros.
215 */
216
217 #define netif_txq_try_stop(txq, get_desc, start_thrs) \
218 ({ \
219 int _res; \
220 \
221 netif_tx_stop_queue(txq); \
222 /* Producer index and stop bit must be visible \
223 * to consumer before we recheck. \
224 * Pairs with a barrier in __netif_txq_completed_wake(). \
225 */ \
226 smp_mb__after_atomic(); \
227 \
228 /* We need to check again in a case another \
229 * CPU has just made room available. \
230 */ \
231 _res = 0; \
232 if (unlikely(get_desc >= start_thrs)) { \
233 netif_tx_start_queue(txq); \
234 _res = -1; \
235 } \
236 _res; \
237 }) \
238
239 /**
240 * netif_txq_maybe_stop() - locklessly stop a Tx queue, if needed
241 * @txq: struct netdev_queue to stop/start
242 * @get_desc: get current number of free descriptors (see requirements below!)
243 * @stop_thrs: minimal number of available descriptors for queue to be left
244 * enabled
245 * @start_thrs: minimal number of descriptors to re-enable the queue, can be
246 * equal to @stop_thrs or higher to avoid frequent waking
247 *
248 * All arguments may be evaluated multiple times, beware of side effects.
249 * @get_desc must be a formula or a function call, it must always
250 * return up-to-date information when evaluated!
251 * Expected to be used from ndo_start_xmit, see the comment on top of the file.
252 *
253 * Returns:
254 * 0 if the queue was stopped
255 * 1 if the queue was left enabled
256 * -1 if the queue was re-enabled (raced with waking)
257 */
258 #define netif_txq_maybe_stop(txq, get_desc, stop_thrs, start_thrs) \
259 ({ \
260 int _res; \
261 \
262 _res = 1; \
263 if (unlikely(get_desc < stop_thrs)) \
264 _res = netif_txq_try_stop(txq, get_desc, start_thrs); \
265 _res; \
266 }) \
267
268 /* Variant of netdev_tx_completed_queue() which guarantees smp_mb() if
269 * @bytes != 0, regardless of kernel config.
270 */
271 static inline void
netdev_txq_completed_mb(struct netdev_queue * dev_queue,unsigned int pkts,unsigned int bytes)272 netdev_txq_completed_mb(struct netdev_queue *dev_queue,
273 unsigned int pkts, unsigned int bytes)
274 {
275 if (IS_ENABLED(CONFIG_BQL))
276 netdev_tx_completed_queue(dev_queue, pkts, bytes);
277 else if (bytes)
278 smp_mb();
279 }
280
281 /**
282 * __netif_txq_completed_wake() - locklessly wake a Tx queue, if needed
283 * @txq: struct netdev_queue to stop/start
284 * @pkts: number of packets completed
285 * @bytes: number of bytes completed
286 * @get_desc: get current number of free descriptors (see requirements below!)
287 * @start_thrs: minimal number of descriptors to re-enable the queue
288 * @down_cond: down condition, predicate indicating that the queue should
289 * not be woken up even if descriptors are available
290 *
291 * All arguments may be evaluated multiple times.
292 * @get_desc must be a formula or a function call, it must always
293 * return up-to-date information when evaluated!
294 * Reports completed pkts/bytes to BQL.
295 *
296 * Returns:
297 * 0 if the queue was woken up
298 * 1 if the queue was already enabled (or disabled but @down_cond is true)
299 * -1 if the queue was left unchanged (@start_thrs not reached)
300 */
301 #define __netif_txq_completed_wake(txq, pkts, bytes, \
302 get_desc, start_thrs, down_cond) \
303 ({ \
304 int _res; \
305 \
306 /* Report to BQL and piggy back on its barrier. \
307 * Barrier makes sure that anybody stopping the queue \
308 * after this point sees the new consumer index. \
309 * Pairs with barrier in netif_txq_try_stop(). \
310 */ \
311 netdev_txq_completed_mb(txq, pkts, bytes); \
312 \
313 _res = -1; \
314 if (pkts && likely(get_desc >= start_thrs)) { \
315 _res = 1; \
316 if (unlikely(netif_tx_queue_stopped(txq)) && \
317 !(down_cond)) { \
318 netif_tx_wake_queue(txq); \
319 _res = 0; \
320 } \
321 } \
322 _res; \
323 })
324
325 #define netif_txq_completed_wake(txq, pkts, bytes, get_desc, start_thrs) \
326 __netif_txq_completed_wake(txq, pkts, bytes, get_desc, start_thrs, false)
327
328 /* subqueue variants follow */
329
330 #define netif_subqueue_try_stop(dev, idx, get_desc, start_thrs) \
331 ({ \
332 struct netdev_queue *_txq; \
333 \
334 _txq = netdev_get_tx_queue(dev, idx); \
335 netif_txq_try_stop(_txq, get_desc, start_thrs); \
336 })
337
netif_subqueue_sent(const struct net_device * dev,unsigned int idx,unsigned int bytes)338 static inline void netif_subqueue_sent(const struct net_device *dev,
339 unsigned int idx, unsigned int bytes)
340 {
341 struct netdev_queue *txq;
342
343 txq = netdev_get_tx_queue(dev, idx);
344 netdev_tx_sent_queue(txq, bytes);
345 }
346
netif_xmit_timeout_ms(struct netdev_queue * txq)347 static inline unsigned int netif_xmit_timeout_ms(struct netdev_queue *txq)
348 {
349 unsigned long trans_start = READ_ONCE(txq->trans_start);
350
351 if (netif_xmit_stopped(txq) &&
352 time_after(jiffies, trans_start + txq->dev->watchdog_timeo))
353 return jiffies_to_msecs(jiffies - trans_start);
354
355 return 0;
356 }
357
358 #define netif_subqueue_maybe_stop(dev, idx, get_desc, stop_thrs, start_thrs) \
359 ({ \
360 struct netdev_queue *_txq; \
361 \
362 _txq = netdev_get_tx_queue(dev, idx); \
363 netif_txq_maybe_stop(_txq, get_desc, stop_thrs, start_thrs); \
364 })
365
366 #define netif_subqueue_completed_wake(dev, idx, pkts, bytes, \
367 get_desc, start_thrs) \
368 ({ \
369 struct netdev_queue *_txq; \
370 \
371 _txq = netdev_get_tx_queue(dev, idx); \
372 netif_txq_completed_wake(_txq, pkts, bytes, \
373 get_desc, start_thrs); \
374 })
375
376 struct device *netdev_queue_get_dma_dev(struct net_device *dev, int idx);
377
378 #endif
379