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