net/sched/sch_mqprio_lib.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2
   3 #include <linux/net.h>
   4 #include <linux/netdevice.h>
   5 #include <linux/netlink.h>
   6 #include <linux/types.h>
   7 #include <net/pkt_sched.h>
   8
   9 #include "sch_mqprio_lib.h"
  10
  11 /* Returns true if the intervals [a, b) and [c, d) overlap. */
  12 static bool intervals_overlap(int a, int b, int c, int d)
  13 {
  14         int left = max(a, c), right = min(b, d);
  15
  16         return left < right;
  17 }
  18
  19 static int mqprio_validate_queue_counts(struct net_device *dev,
  20                                         const struct tc_mqprio_qopt *qopt,
  21                                         bool allow_overlapping_txqs,
  22                                         struct netlink_ext_ack *extack)
  23 {
  24         int i, j;
  25
  26         for (i = 0; i < qopt->num_tc; i++) {
  27                 unsigned int last = qopt->offset[i] + qopt->count[i];
  28
  29                 if (!qopt->count[i]) {
  30                         NL_SET_ERR_MSG_FMT_MOD(extack, "No queues for TC %d",
  31                                                i);
  32                         return -EINVAL;
  33                 }
  34
  35                 /* Verify the queue count is in tx range being equal to the
  36                  * real_num_tx_queues indicates the last queue is in use.
  37                  */
  38                 if (qopt->offset[i] >= dev->real_num_tx_queues ||
  39                     last > dev->real_num_tx_queues) {
  40                         NL_SET_ERR_MSG_FMT_MOD(extack,
  41                                                "Queues %d:%d for TC %d exceed the %d TX queues available",
  42                                                qopt->count[i], qopt->offset[i],
  43                                                i, dev->real_num_tx_queues);
  44                         return -EINVAL;
  45                 }
  46
  47                 if (allow_overlapping_txqs)
  48                         continue;
  49
  50                 /* Verify that the offset and counts do not overlap */
  51                 for (j = i + 1; j < qopt->num_tc; j++) {
  52                         if (intervals_overlap(qopt->offset[i], last,
  53                                               qopt->offset[j],
  54                                               qopt->offset[j] +
  55                                               qopt->count[j])) {
  56                                 NL_SET_ERR_MSG_FMT_MOD(extack,
  57                                                        "TC %d queues %d@%d overlap with TC %d queues %d@%d",
  58                                                        i, qopt->count[i], qopt->offset[i],
  59                                                        j, qopt->count[j], qopt->offset[j]);
  60                                 return -EINVAL;
  61                         }
  62                 }
  63         }
  64
  65         return 0;
  66 }
  67
  68 int mqprio_validate_qopt(struct net_device *dev, struct tc_mqprio_qopt *qopt,
  69                          bool validate_queue_counts,
  70                          bool allow_overlapping_txqs,
  71                          struct netlink_ext_ack *extack)
  72 {
  73         int i, err;
  74
  75         /* Verify num_tc is not out of max range */
  76         if (qopt->num_tc > TC_MAX_QUEUE) {
  77                 NL_SET_ERR_MSG(extack,
  78                                "Number of traffic classes is outside valid range");
  79                 return -EINVAL;
  80         }
  81
  82         /* Verify priority mapping uses valid tcs */
  83         for (i = 0; i <= TC_BITMASK; i++) {
  84                 if (qopt->prio_tc_map[i] >= qopt->num_tc) {
  85                         NL_SET_ERR_MSG(extack,
  86                                        "Invalid traffic class in priority to traffic class mapping");
  87                         return -EINVAL;
  88                 }
  89         }
  90
  91         if (validate_queue_counts) {
  92                 err = mqprio_validate_queue_counts(dev, qopt,
  93                                                    allow_overlapping_txqs,
  94                                                    extack);
  95                 if (err)
  96                         return err;
  97         }
  98
  99         return 0;
 100 }
 101 EXPORT_SYMBOL_GPL(mqprio_validate_qopt);
 102
 103 void mqprio_qopt_reconstruct(struct net_device *dev, struct tc_mqprio_qopt *qopt)
 104 {
 105         int tc, num_tc = netdev_get_num_tc(dev);
 106
 107         qopt->num_tc = num_tc;
 108         memcpy(qopt->prio_tc_map, dev->prio_tc_map, sizeof(qopt->prio_tc_map));
 109
 110         for (tc = 0; tc < num_tc; tc++) {
 111                 qopt->count[tc] = dev->tc_to_txq[tc].count;
 112                 qopt->offset[tc] = dev->tc_to_txq[tc].offset;
 113         }
 114 }
 115 EXPORT_SYMBOL_GPL(mqprio_qopt_reconstruct);
 116
 117 void mqprio_fp_to_offload(u32 fp[TC_QOPT_MAX_QUEUE],
 118                           struct tc_mqprio_qopt_offload *mqprio)
 119 {
 120         unsigned long preemptible_tcs = 0;
 121         int tc;
 122
 123         for (tc = 0; tc < TC_QOPT_MAX_QUEUE; tc++)
 124                 if (fp[tc] == TC_FP_PREEMPTIBLE)
 125                         preemptible_tcs |= BIT(tc);
 126
 127         mqprio->preemptible_tcs = preemptible_tcs;
 128 }
 129 EXPORT_SYMBOL_GPL(mqprio_fp_to_offload);
 130
 131 MODULE_LICENSE("GPL");
 132 MODULE_DESCRIPTION("Shared mqprio qdisc code currently between taprio and mqprio");