linux/include/net/pkt_sched.h
Vladimir Oltean 847cbfc014 net: add a helper to avoid issues with HW TX timestamping and SO_TXTIME
As explained in commit 29d98f54a4 ("net: enetc: allow hardware
timestamping on TX queues with tc-etf enabled"), hardware TX
timestamping requires an skb with skb->tstamp = 0. When a packet is sent
with SO_TXTIME, the skb->skb_mstamp_ns corrupts the value of skb->tstamp,
so the drivers need to explicitly reset skb->tstamp to zero after
consuming the TX time.

Create a helper named skb_txtime_consumed() which does just that. All
drivers which offload TC_SETUP_QDISC_ETF should implement it, and it
would make it easier to assess during review whether they do the right
thing in order to be compatible with hardware timestamping or not.

Suggested-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Acked-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-03-10 12:45:16 -08:00

201 lines
5.2 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __NET_PKT_SCHED_H
#define __NET_PKT_SCHED_H
#include <linux/jiffies.h>
#include <linux/ktime.h>
#include <linux/if_vlan.h>
#include <linux/netdevice.h>
#include <net/sch_generic.h>
#include <net/net_namespace.h>
#include <uapi/linux/pkt_sched.h>
#define DEFAULT_TX_QUEUE_LEN 1000
struct qdisc_walker {
int stop;
int skip;
int count;
int (*fn)(struct Qdisc *, unsigned long cl, struct qdisc_walker *);
};
static inline void *qdisc_priv(struct Qdisc *q)
{
return &q->privdata;
}
static inline struct Qdisc *qdisc_from_priv(void *priv)
{
return container_of(priv, struct Qdisc, privdata);
}
/*
Timer resolution MUST BE < 10% of min_schedulable_packet_size/bandwidth
Normal IP packet size ~ 512byte, hence:
0.5Kbyte/1Mbyte/sec = 0.5msec, so that we need 50usec timer for
10Mbit ethernet.
10msec resolution -> <50Kbit/sec.
The result: [34]86 is not good choice for QoS router :-(
The things are not so bad, because we may use artificial
clock evaluated by integration of network data flow
in the most critical places.
*/
typedef u64 psched_time_t;
typedef long psched_tdiff_t;
/* Avoid doing 64 bit divide */
#define PSCHED_SHIFT 6
#define PSCHED_TICKS2NS(x) ((s64)(x) << PSCHED_SHIFT)
#define PSCHED_NS2TICKS(x) ((x) >> PSCHED_SHIFT)
#define PSCHED_TICKS_PER_SEC PSCHED_NS2TICKS(NSEC_PER_SEC)
#define PSCHED_PASTPERFECT 0
static inline psched_time_t psched_get_time(void)
{
return PSCHED_NS2TICKS(ktime_get_ns());
}
static inline psched_tdiff_t
psched_tdiff_bounded(psched_time_t tv1, psched_time_t tv2, psched_time_t bound)
{
return min(tv1 - tv2, bound);
}
struct qdisc_watchdog {
u64 last_expires;
struct hrtimer timer;
struct Qdisc *qdisc;
};
void qdisc_watchdog_init_clockid(struct qdisc_watchdog *wd, struct Qdisc *qdisc,
clockid_t clockid);
void qdisc_watchdog_init(struct qdisc_watchdog *wd, struct Qdisc *qdisc);
void qdisc_watchdog_schedule_range_ns(struct qdisc_watchdog *wd, u64 expires,
u64 delta_ns);
static inline void qdisc_watchdog_schedule_ns(struct qdisc_watchdog *wd,
u64 expires)
{
return qdisc_watchdog_schedule_range_ns(wd, expires, 0ULL);
}
static inline void qdisc_watchdog_schedule(struct qdisc_watchdog *wd,
psched_time_t expires)
{
qdisc_watchdog_schedule_ns(wd, PSCHED_TICKS2NS(expires));
}
void qdisc_watchdog_cancel(struct qdisc_watchdog *wd);
extern struct Qdisc_ops pfifo_qdisc_ops;
extern struct Qdisc_ops bfifo_qdisc_ops;
extern struct Qdisc_ops pfifo_head_drop_qdisc_ops;
int fifo_set_limit(struct Qdisc *q, unsigned int limit);
struct Qdisc *fifo_create_dflt(struct Qdisc *sch, struct Qdisc_ops *ops,
unsigned int limit,
struct netlink_ext_ack *extack);
int register_qdisc(struct Qdisc_ops *qops);
int unregister_qdisc(struct Qdisc_ops *qops);
void qdisc_get_default(char *id, size_t len);
int qdisc_set_default(const char *id);
void qdisc_hash_add(struct Qdisc *q, bool invisible);
void qdisc_hash_del(struct Qdisc *q);
struct Qdisc *qdisc_lookup(struct net_device *dev, u32 handle);
struct Qdisc *qdisc_lookup_rcu(struct net_device *dev, u32 handle);
struct qdisc_rate_table *qdisc_get_rtab(struct tc_ratespec *r,
struct nlattr *tab,
struct netlink_ext_ack *extack);
void qdisc_put_rtab(struct qdisc_rate_table *tab);
void qdisc_put_stab(struct qdisc_size_table *tab);
void qdisc_warn_nonwc(const char *txt, struct Qdisc *qdisc);
bool sch_direct_xmit(struct sk_buff *skb, struct Qdisc *q,
struct net_device *dev, struct netdev_queue *txq,
spinlock_t *root_lock, bool validate);
void __qdisc_run(struct Qdisc *q);
static inline void qdisc_run(struct Qdisc *q)
{
if (qdisc_run_begin(q)) {
/* NOLOCK qdisc must check 'state' under the qdisc seqlock
* to avoid racing with dev_qdisc_reset()
*/
if (!(q->flags & TCQ_F_NOLOCK) ||
likely(!test_bit(__QDISC_STATE_DEACTIVATED, &q->state)))
__qdisc_run(q);
qdisc_run_end(q);
}
}
/* Calculate maximal size of packet seen by hard_start_xmit
routine of this device.
*/
static inline unsigned int psched_mtu(const struct net_device *dev)
{
return dev->mtu + dev->hard_header_len;
}
static inline struct net *qdisc_net(struct Qdisc *q)
{
return dev_net(q->dev_queue->dev);
}
struct tc_cbs_qopt_offload {
u8 enable;
s32 queue;
s32 hicredit;
s32 locredit;
s32 idleslope;
s32 sendslope;
};
struct tc_etf_qopt_offload {
u8 enable;
s32 queue;
};
struct tc_taprio_sched_entry {
u8 command; /* TC_TAPRIO_CMD_* */
/* The gate_mask in the offloading side refers to traffic classes */
u32 gate_mask;
u32 interval;
};
struct tc_taprio_qopt_offload {
u8 enable;
ktime_t base_time;
u64 cycle_time;
u64 cycle_time_extension;
size_t num_entries;
struct tc_taprio_sched_entry entries[];
};
/* Reference counting */
struct tc_taprio_qopt_offload *taprio_offload_get(struct tc_taprio_qopt_offload
*offload);
void taprio_offload_free(struct tc_taprio_qopt_offload *offload);
/* Ensure skb_mstamp_ns, which might have been populated with the txtime, is
* not mistaken for a software timestamp, because this will otherwise prevent
* the dispatch of hardware timestamps to the socket.
*/
static inline void skb_txtime_consumed(struct sk_buff *skb)
{
skb->tstamp = ktime_set(0, 0);
}
#endif