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-rw-r--r--debian/patches-rt/0201-net-Qdisc-use-a-seqlock-instead-seqcount.patch293
1 files changed, 293 insertions, 0 deletions
diff --git a/debian/patches-rt/0201-net-Qdisc-use-a-seqlock-instead-seqcount.patch b/debian/patches-rt/0201-net-Qdisc-use-a-seqlock-instead-seqcount.patch
new file mode 100644
index 000000000..8d15d62a7
--- /dev/null
+++ b/debian/patches-rt/0201-net-Qdisc-use-a-seqlock-instead-seqcount.patch
@@ -0,0 +1,293 @@
+From 561eb0fa2d08a2b919983a6deaaef8022a6d0707 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Wed, 14 Sep 2016 17:36:35 +0200
+Subject: [PATCH 201/347] net/Qdisc: use a seqlock instead seqcount
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.246-rt110.tar.xz
+
+The seqcount disables preemption on -RT while it is held which can't
+remove. Also we don't want the reader to spin for ages if the writer is
+scheduled out. The seqlock on the other hand will serialize / sleep on
+the lock while writer is active.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/seqlock.h | 9 +++++++++
+ include/net/gen_stats.h | 9 +++++----
+ include/net/net_seq_lock.h | 15 +++++++++++++++
+ include/net/sch_generic.h | 19 +++++++++++++++++--
+ net/core/gen_estimator.c | 6 +++---
+ net/core/gen_stats.c | 8 ++++----
+ net/sched/sch_api.c | 2 +-
+ net/sched/sch_generic.c | 12 ++++++++++++
+ 8 files changed, 66 insertions(+), 14 deletions(-)
+ create mode 100644 include/net/net_seq_lock.h
+
+diff --git a/include/linux/seqlock.h b/include/linux/seqlock.h
+index a3768cfce914..31bc2cc99bf0 100644
+--- a/include/linux/seqlock.h
++++ b/include/linux/seqlock.h
+@@ -489,6 +489,15 @@ static inline void write_seqlock(seqlock_t *sl)
+ __raw_write_seqcount_begin(&sl->seqcount);
+ }
+
++static inline int try_write_seqlock(seqlock_t *sl)
++{
++ if (spin_trylock(&sl->lock)) {
++ __raw_write_seqcount_begin(&sl->seqcount);
++ return 1;
++ }
++ return 0;
++}
++
+ static inline void write_sequnlock(seqlock_t *sl)
+ {
+ __raw_write_seqcount_end(&sl->seqcount);
+diff --git a/include/net/gen_stats.h b/include/net/gen_stats.h
+index 883bb9085f15..3b593cdeb9af 100644
+--- a/include/net/gen_stats.h
++++ b/include/net/gen_stats.h
+@@ -6,6 +6,7 @@
+ #include <linux/socket.h>
+ #include <linux/rtnetlink.h>
+ #include <linux/pkt_sched.h>
++#include <net/net_seq_lock.h>
+
+ struct gnet_stats_basic_cpu {
+ struct gnet_stats_basic_packed bstats;
+@@ -36,11 +37,11 @@ int gnet_stats_start_copy_compat(struct sk_buff *skb, int type,
+ spinlock_t *lock, struct gnet_dump *d,
+ int padattr);
+
+-int gnet_stats_copy_basic(const seqcount_t *running,
++int gnet_stats_copy_basic(net_seqlock_t *running,
+ struct gnet_dump *d,
+ struct gnet_stats_basic_cpu __percpu *cpu,
+ struct gnet_stats_basic_packed *b);
+-void __gnet_stats_copy_basic(const seqcount_t *running,
++void __gnet_stats_copy_basic(net_seqlock_t *running,
+ struct gnet_stats_basic_packed *bstats,
+ struct gnet_stats_basic_cpu __percpu *cpu,
+ struct gnet_stats_basic_packed *b);
+@@ -60,13 +61,13 @@ int gen_new_estimator(struct gnet_stats_basic_packed *bstats,
+ struct gnet_stats_basic_cpu __percpu *cpu_bstats,
+ struct net_rate_estimator __rcu **rate_est,
+ spinlock_t *lock,
+- seqcount_t *running, struct nlattr *opt);
++ net_seqlock_t *running, struct nlattr *opt);
+ void gen_kill_estimator(struct net_rate_estimator __rcu **ptr);
+ int gen_replace_estimator(struct gnet_stats_basic_packed *bstats,
+ struct gnet_stats_basic_cpu __percpu *cpu_bstats,
+ struct net_rate_estimator __rcu **ptr,
+ spinlock_t *lock,
+- seqcount_t *running, struct nlattr *opt);
++ net_seqlock_t *running, struct nlattr *opt);
+ bool gen_estimator_active(struct net_rate_estimator __rcu **ptr);
+ bool gen_estimator_read(struct net_rate_estimator __rcu **ptr,
+ struct gnet_stats_rate_est64 *sample);
+diff --git a/include/net/net_seq_lock.h b/include/net/net_seq_lock.h
+new file mode 100644
+index 000000000000..a7034298a82a
+--- /dev/null
++++ b/include/net/net_seq_lock.h
+@@ -0,0 +1,15 @@
++#ifndef __NET_NET_SEQ_LOCK_H__
++#define __NET_NET_SEQ_LOCK_H__
++
++#ifdef CONFIG_PREEMPT_RT_BASE
++# define net_seqlock_t seqlock_t
++# define net_seq_begin(__r) read_seqbegin(__r)
++# define net_seq_retry(__r, __s) read_seqretry(__r, __s)
++
++#else
++# define net_seqlock_t seqcount_t
++# define net_seq_begin(__r) read_seqcount_begin(__r)
++# define net_seq_retry(__r, __s) read_seqcount_retry(__r, __s)
++#endif
++
++#endif
+diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
+index 483303adf3df..038204c7b05e 100644
+--- a/include/net/sch_generic.h
++++ b/include/net/sch_generic.h
+@@ -10,6 +10,7 @@
+ #include <linux/percpu.h>
+ #include <linux/dynamic_queue_limits.h>
+ #include <linux/list.h>
++#include <net/net_seq_lock.h>
+ #include <linux/refcount.h>
+ #include <linux/workqueue.h>
+ #include <net/gen_stats.h>
+@@ -100,7 +101,7 @@ struct Qdisc {
+ struct sk_buff_head gso_skb ____cacheline_aligned_in_smp;
+ struct qdisc_skb_head q;
+ struct gnet_stats_basic_packed bstats;
+- seqcount_t running;
++ net_seqlock_t running;
+ struct gnet_stats_queue qstats;
+ unsigned long state;
+ struct Qdisc *next_sched;
+@@ -135,7 +136,11 @@ static inline bool qdisc_is_running(struct Qdisc *qdisc)
+ {
+ if (qdisc->flags & TCQ_F_NOLOCK)
+ return spin_is_locked(&qdisc->seqlock);
++#ifdef CONFIG_PREEMPT_RT_BASE
++ return spin_is_locked(&qdisc->running.lock) ? true : false;
++#else
+ return (raw_read_seqcount(&qdisc->running) & 1) ? true : false;
++#endif
+ }
+
+ static inline bool qdisc_run_begin(struct Qdisc *qdisc)
+@@ -146,17 +151,27 @@ static inline bool qdisc_run_begin(struct Qdisc *qdisc)
+ } else if (qdisc_is_running(qdisc)) {
+ return false;
+ }
++#ifdef CONFIG_PREEMPT_RT_BASE
++ if (try_write_seqlock(&qdisc->running))
++ return true;
++ return false;
++#else
+ /* Variant of write_seqcount_begin() telling lockdep a trylock
+ * was attempted.
+ */
+ raw_write_seqcount_begin(&qdisc->running);
+ seqcount_acquire(&qdisc->running.dep_map, 0, 1, _RET_IP_);
+ return true;
++#endif
+ }
+
+ static inline void qdisc_run_end(struct Qdisc *qdisc)
+ {
++#ifdef CONFIG_PREEMPT_RT_BASE
++ write_sequnlock(&qdisc->running);
++#else
+ write_seqcount_end(&qdisc->running);
++#endif
+ if (qdisc->flags & TCQ_F_NOLOCK)
+ spin_unlock(&qdisc->seqlock);
+ }
+@@ -475,7 +490,7 @@ static inline spinlock_t *qdisc_root_sleeping_lock(const struct Qdisc *qdisc)
+ return qdisc_lock(root);
+ }
+
+-static inline seqcount_t *qdisc_root_sleeping_running(const struct Qdisc *qdisc)
++static inline net_seqlock_t *qdisc_root_sleeping_running(const struct Qdisc *qdisc)
+ {
+ struct Qdisc *root = qdisc_root_sleeping(qdisc);
+
+diff --git a/net/core/gen_estimator.c b/net/core/gen_estimator.c
+index 752744db11ff..7112e28b4130 100644
+--- a/net/core/gen_estimator.c
++++ b/net/core/gen_estimator.c
+@@ -46,7 +46,7 @@
+ struct net_rate_estimator {
+ struct gnet_stats_basic_packed *bstats;
+ spinlock_t *stats_lock;
+- seqcount_t *running;
++ net_seqlock_t *running;
+ struct gnet_stats_basic_cpu __percpu *cpu_bstats;
+ u8 ewma_log;
+ u8 intvl_log; /* period : (250ms << intvl_log) */
+@@ -129,7 +129,7 @@ int gen_new_estimator(struct gnet_stats_basic_packed *bstats,
+ struct gnet_stats_basic_cpu __percpu *cpu_bstats,
+ struct net_rate_estimator __rcu **rate_est,
+ spinlock_t *lock,
+- seqcount_t *running,
++ net_seqlock_t *running,
+ struct nlattr *opt)
+ {
+ struct gnet_estimator *parm = nla_data(opt);
+@@ -230,7 +230,7 @@ int gen_replace_estimator(struct gnet_stats_basic_packed *bstats,
+ struct gnet_stats_basic_cpu __percpu *cpu_bstats,
+ struct net_rate_estimator __rcu **rate_est,
+ spinlock_t *lock,
+- seqcount_t *running, struct nlattr *opt)
++ net_seqlock_t *running, struct nlattr *opt)
+ {
+ return gen_new_estimator(bstats, cpu_bstats, rate_est,
+ lock, running, opt);
+diff --git a/net/core/gen_stats.c b/net/core/gen_stats.c
+index e2fd8baec65f..8bab88738691 100644
+--- a/net/core/gen_stats.c
++++ b/net/core/gen_stats.c
+@@ -142,7 +142,7 @@ __gnet_stats_copy_basic_cpu(struct gnet_stats_basic_packed *bstats,
+ }
+
+ void
+-__gnet_stats_copy_basic(const seqcount_t *running,
++__gnet_stats_copy_basic(net_seqlock_t *running,
+ struct gnet_stats_basic_packed *bstats,
+ struct gnet_stats_basic_cpu __percpu *cpu,
+ struct gnet_stats_basic_packed *b)
+@@ -155,10 +155,10 @@ __gnet_stats_copy_basic(const seqcount_t *running,
+ }
+ do {
+ if (running)
+- seq = read_seqcount_begin(running);
++ seq = net_seq_begin(running);
+ bstats->bytes = b->bytes;
+ bstats->packets = b->packets;
+- } while (running && read_seqcount_retry(running, seq));
++ } while (running && net_seq_retry(running, seq));
+ }
+ EXPORT_SYMBOL(__gnet_stats_copy_basic);
+
+@@ -176,7 +176,7 @@ EXPORT_SYMBOL(__gnet_stats_copy_basic);
+ * if the room in the socket buffer was not sufficient.
+ */
+ int
+-gnet_stats_copy_basic(const seqcount_t *running,
++gnet_stats_copy_basic(net_seqlock_t *running,
+ struct gnet_dump *d,
+ struct gnet_stats_basic_cpu __percpu *cpu,
+ struct gnet_stats_basic_packed *b)
+diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
+index 424e70907b96..6b4ee7c98d69 100644
+--- a/net/sched/sch_api.c
++++ b/net/sched/sch_api.c
+@@ -1191,7 +1191,7 @@ static struct Qdisc *qdisc_create(struct net_device *dev,
+ rcu_assign_pointer(sch->stab, stab);
+ }
+ if (tca[TCA_RATE]) {
+- seqcount_t *running;
++ net_seqlock_t *running;
+
+ err = -EOPNOTSUPP;
+ if (sch->flags & TCQ_F_MQROOT) {
+diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
+index 42a776abdf2f..cc4c4309a2b8 100644
+--- a/net/sched/sch_generic.c
++++ b/net/sched/sch_generic.c
+@@ -576,7 +576,11 @@ struct Qdisc noop_qdisc = {
+ .ops = &noop_qdisc_ops,
+ .q.lock = __SPIN_LOCK_UNLOCKED(noop_qdisc.q.lock),
+ .dev_queue = &noop_netdev_queue,
++#ifdef CONFIG_PREEMPT_RT_BASE
++ .running = __SEQLOCK_UNLOCKED(noop_qdisc.running),
++#else
+ .running = SEQCNT_ZERO(noop_qdisc.running),
++#endif
+ .busylock = __SPIN_LOCK_UNLOCKED(noop_qdisc.busylock),
+ .gso_skb = {
+ .next = (struct sk_buff *)&noop_qdisc.gso_skb,
+@@ -877,9 +881,17 @@ struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
+ lockdep_set_class(&sch->busylock,
+ dev->qdisc_tx_busylock ?: &qdisc_tx_busylock);
+
++#ifdef CONFIG_PREEMPT_RT_BASE
++ seqlock_init(&sch->running);
++ lockdep_set_class(&sch->running.seqcount,
++ dev->qdisc_running_key ?: &qdisc_running_key);
++ lockdep_set_class(&sch->running.lock,
++ dev->qdisc_running_key ?: &qdisc_running_key);
++#else
+ seqcount_init(&sch->running);
+ lockdep_set_class(&sch->running,
+ dev->qdisc_running_key ?: &qdisc_running_key);
++#endif
+
+ sch->ops = ops;
+ sch->flags = ops->static_flags;
+--
+2.36.1
+
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-25 13:31:54 +0000