[PATCH rcu 11/20] srcu: Move grace-period fields from srcu_struct to srcu_usage

From: Paul E. McKenney
Date: Thu Mar 30 2023 - 18:49:09 EST


This commit moves the ->srcu_gp_seq, ->srcu_gp_seq_needed,
->srcu_gp_seq_needed_exp, ->srcu_gp_start, and ->srcu_last_gp_end fields
from the srcu_struct structure to the srcu_usage structure to reduce
the size of the former in order to improve cache locality.

Suggested-by: Christoph Hellwig <hch@xxxxxx>
Tested-by: Sachin Sant <sachinp@xxxxxxxxxxxxx>
Tested-by: "Zhang, Qiang1" <qiang1.zhang@xxxxxxxxx>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
---
include/linux/srcutree.h | 25 ++++----
kernel/rcu/srcutree.c | 128 +++++++++++++++++++--------------------
2 files changed, 77 insertions(+), 76 deletions(-)

diff --git a/include/linux/srcutree.h b/include/linux/srcutree.h
index d04e3da6181c..372e35b0e8b6 100644
--- a/include/linux/srcutree.h
+++ b/include/linux/srcutree.h
@@ -68,6 +68,11 @@ struct srcu_usage {
struct mutex srcu_cb_mutex; /* Serialize CB preparation. */
spinlock_t __private lock; /* Protect counters and size state. */
struct mutex srcu_gp_mutex; /* Serialize GP work. */
+ unsigned long srcu_gp_seq; /* Grace-period seq #. */
+ unsigned long srcu_gp_seq_needed; /* Latest gp_seq needed. */
+ unsigned long srcu_gp_seq_needed_exp; /* Furthest future exp GP. */
+ unsigned long srcu_gp_start; /* Last GP start timestamp (jiffies) */
+ unsigned long srcu_last_gp_end; /* Last GP end timestamp (ns) */
};

/*
@@ -75,11 +80,6 @@ struct srcu_usage {
*/
struct srcu_struct {
unsigned int srcu_idx; /* Current rdr array element. */
- unsigned long srcu_gp_seq; /* Grace-period seq #. */
- unsigned long srcu_gp_seq_needed; /* Latest gp_seq needed. */
- unsigned long srcu_gp_seq_needed_exp; /* Furthest future exp GP. */
- unsigned long srcu_gp_start; /* Last GP start timestamp (jiffies) */
- unsigned long srcu_last_gp_end; /* Last GP end timestamp (ns) */
unsigned long srcu_size_jiffies; /* Current contention-measurement interval. */
unsigned long srcu_n_lock_retries; /* Contention events in current interval. */
unsigned long srcu_n_exp_nodelay; /* # expedited no-delays in current GP phase. */
@@ -115,8 +115,13 @@ struct srcu_struct {
#define SRCU_STATE_SCAN1 1
#define SRCU_STATE_SCAN2 2

-#define __SRCU_STRUCT_INIT_COMMON(name, usage_name) \
+#define __SRCU_USAGE_INIT(name) \
+{ \
+ .lock = __SPIN_LOCK_UNLOCKED(name.lock), \
.srcu_gp_seq_needed = -1UL, \
+}
+
+#define __SRCU_STRUCT_INIT_COMMON(name, usage_name) \
.work = __DELAYED_WORK_INITIALIZER(name.work, NULL, 0), \
.srcu_sup = &usage_name, \
__SRCU_DEP_MAP_INIT(name)
@@ -153,9 +158,7 @@ struct srcu_struct {
*/
#ifdef MODULE
# define __DEFINE_SRCU(name, is_static) \
- static struct srcu_usage name##_srcu_usage = { \
- .lock = __SPIN_LOCK_UNLOCKED(name.lock), \
- }; \
+ static struct srcu_usage name##_srcu_usage = __SRCU_USAGE_INIT(name##_srcu_usage); \
is_static struct srcu_struct name = __SRCU_STRUCT_INIT_MODULE(name, name##_srcu_usage); \
extern struct srcu_struct * const __srcu_struct_##name; \
struct srcu_struct * const __srcu_struct_##name \
@@ -163,9 +166,7 @@ struct srcu_struct {
#else
# define __DEFINE_SRCU(name, is_static) \
static DEFINE_PER_CPU(struct srcu_data, name##_srcu_data); \
- static struct srcu_usage name##_srcu_usage = { \
- .lock = __SPIN_LOCK_UNLOCKED(name.lock), \
- }; \
+ static struct srcu_usage name##_srcu_usage = __SRCU_USAGE_INIT(name##_srcu_usage); \
is_static struct srcu_struct name = \
__SRCU_STRUCT_INIT(name, name##_srcu_usage, name##_srcu_data)
#endif
diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c
index a36066798de7..340eb685cf64 100644
--- a/kernel/rcu/srcutree.c
+++ b/kernel/rcu/srcutree.c
@@ -135,8 +135,8 @@ static void init_srcu_struct_data(struct srcu_struct *ssp)
spin_lock_init(&ACCESS_PRIVATE(sdp, lock));
rcu_segcblist_init(&sdp->srcu_cblist);
sdp->srcu_cblist_invoking = false;
- sdp->srcu_gp_seq_needed = ssp->srcu_gp_seq;
- sdp->srcu_gp_seq_needed_exp = ssp->srcu_gp_seq;
+ sdp->srcu_gp_seq_needed = ssp->srcu_sup->srcu_gp_seq;
+ sdp->srcu_gp_seq_needed_exp = ssp->srcu_sup->srcu_gp_seq;
sdp->mynode = NULL;
sdp->cpu = cpu;
INIT_WORK(&sdp->work, srcu_invoke_callbacks);
@@ -247,7 +247,7 @@ static int init_srcu_struct_fields(struct srcu_struct *ssp, bool is_static)
mutex_init(&ssp->srcu_sup->srcu_cb_mutex);
mutex_init(&ssp->srcu_sup->srcu_gp_mutex);
ssp->srcu_idx = 0;
- ssp->srcu_gp_seq = 0;
+ ssp->srcu_sup->srcu_gp_seq = 0;
ssp->srcu_barrier_seq = 0;
mutex_init(&ssp->srcu_barrier_mutex);
atomic_set(&ssp->srcu_barrier_cpu_cnt, 0);
@@ -261,8 +261,8 @@ static int init_srcu_struct_fields(struct srcu_struct *ssp, bool is_static)
return -ENOMEM;
}
init_srcu_struct_data(ssp);
- ssp->srcu_gp_seq_needed_exp = 0;
- ssp->srcu_last_gp_end = ktime_get_mono_fast_ns();
+ ssp->srcu_sup->srcu_gp_seq_needed_exp = 0;
+ ssp->srcu_sup->srcu_last_gp_end = ktime_get_mono_fast_ns();
if (READ_ONCE(ssp->srcu_sup->srcu_size_state) == SRCU_SIZE_SMALL && SRCU_SIZING_IS_INIT()) {
if (!init_srcu_struct_nodes(ssp, GFP_ATOMIC)) {
if (!ssp->sda_is_static) {
@@ -275,7 +275,7 @@ static int init_srcu_struct_fields(struct srcu_struct *ssp, bool is_static)
WRITE_ONCE(ssp->srcu_sup->srcu_size_state, SRCU_SIZE_BIG);
}
}
- smp_store_release(&ssp->srcu_gp_seq_needed, 0); /* Init done. */
+ smp_store_release(&ssp->srcu_sup->srcu_gp_seq_needed, 0); /* Init done. */
return 0;
}

@@ -402,10 +402,10 @@ static void check_init_srcu_struct(struct srcu_struct *ssp)
unsigned long flags;

/* The smp_load_acquire() pairs with the smp_store_release(). */
- if (!rcu_seq_state(smp_load_acquire(&ssp->srcu_gp_seq_needed))) /*^^^*/
+ if (!rcu_seq_state(smp_load_acquire(&ssp->srcu_sup->srcu_gp_seq_needed))) /*^^^*/
return; /* Already initialized. */
spin_lock_irqsave_rcu_node(ssp->srcu_sup, flags);
- if (!rcu_seq_state(ssp->srcu_gp_seq_needed)) {
+ if (!rcu_seq_state(ssp->srcu_sup->srcu_gp_seq_needed)) {
spin_unlock_irqrestore_rcu_node(ssp->srcu_sup, flags);
return;
}
@@ -616,11 +616,11 @@ static unsigned long srcu_get_delay(struct srcu_struct *ssp)
unsigned long j;
unsigned long jbase = SRCU_INTERVAL;

- if (ULONG_CMP_LT(READ_ONCE(ssp->srcu_gp_seq), READ_ONCE(ssp->srcu_gp_seq_needed_exp)))
+ if (ULONG_CMP_LT(READ_ONCE(ssp->srcu_sup->srcu_gp_seq), READ_ONCE(ssp->srcu_sup->srcu_gp_seq_needed_exp)))
jbase = 0;
- if (rcu_seq_state(READ_ONCE(ssp->srcu_gp_seq))) {
+ if (rcu_seq_state(READ_ONCE(ssp->srcu_sup->srcu_gp_seq))) {
j = jiffies - 1;
- gpstart = READ_ONCE(ssp->srcu_gp_start);
+ gpstart = READ_ONCE(ssp->srcu_sup->srcu_gp_start);
if (time_after(j, gpstart))
jbase += j - gpstart;
if (!jbase) {
@@ -656,12 +656,12 @@ void cleanup_srcu_struct(struct srcu_struct *ssp)
if (WARN_ON(rcu_segcblist_n_cbs(&sdp->srcu_cblist)))
return; /* Forgot srcu_barrier(), so just leak it! */
}
- if (WARN_ON(rcu_seq_state(READ_ONCE(ssp->srcu_gp_seq)) != SRCU_STATE_IDLE) ||
- WARN_ON(rcu_seq_current(&ssp->srcu_gp_seq) != ssp->srcu_gp_seq_needed) ||
+ if (WARN_ON(rcu_seq_state(READ_ONCE(ssp->srcu_sup->srcu_gp_seq)) != SRCU_STATE_IDLE) ||
+ WARN_ON(rcu_seq_current(&ssp->srcu_sup->srcu_gp_seq) != ssp->srcu_sup->srcu_gp_seq_needed) ||
WARN_ON(srcu_readers_active(ssp))) {
pr_info("%s: Active srcu_struct %p read state: %d gp state: %lu/%lu\n",
- __func__, ssp, rcu_seq_state(READ_ONCE(ssp->srcu_gp_seq)),
- rcu_seq_current(&ssp->srcu_gp_seq), ssp->srcu_gp_seq_needed);
+ __func__, ssp, rcu_seq_state(READ_ONCE(ssp->srcu_sup->srcu_gp_seq)),
+ rcu_seq_current(&ssp->srcu_sup->srcu_gp_seq), ssp->srcu_sup->srcu_gp_seq_needed);
return; /* Caller forgot to stop doing call_srcu()? */
}
kfree(ssp->srcu_sup->node);
@@ -775,18 +775,18 @@ static void srcu_gp_start(struct srcu_struct *ssp)
else
sdp = this_cpu_ptr(ssp->sda);
lockdep_assert_held(&ACCESS_PRIVATE(ssp->srcu_sup, lock));
- WARN_ON_ONCE(ULONG_CMP_GE(ssp->srcu_gp_seq, ssp->srcu_gp_seq_needed));
+ WARN_ON_ONCE(ULONG_CMP_GE(ssp->srcu_sup->srcu_gp_seq, ssp->srcu_sup->srcu_gp_seq_needed));
spin_lock_rcu_node(sdp); /* Interrupts already disabled. */
rcu_segcblist_advance(&sdp->srcu_cblist,
- rcu_seq_current(&ssp->srcu_gp_seq));
+ rcu_seq_current(&ssp->srcu_sup->srcu_gp_seq));
(void)rcu_segcblist_accelerate(&sdp->srcu_cblist,
- rcu_seq_snap(&ssp->srcu_gp_seq));
+ rcu_seq_snap(&ssp->srcu_sup->srcu_gp_seq));
spin_unlock_rcu_node(sdp); /* Interrupts remain disabled. */
- WRITE_ONCE(ssp->srcu_gp_start, jiffies);
+ WRITE_ONCE(ssp->srcu_sup->srcu_gp_start, jiffies);
WRITE_ONCE(ssp->srcu_n_exp_nodelay, 0);
smp_mb(); /* Order prior store to ->srcu_gp_seq_needed vs. GP start. */
- rcu_seq_start(&ssp->srcu_gp_seq);
- state = rcu_seq_state(ssp->srcu_gp_seq);
+ rcu_seq_start(&ssp->srcu_sup->srcu_gp_seq);
+ state = rcu_seq_state(ssp->srcu_sup->srcu_gp_seq);
WARN_ON_ONCE(state != SRCU_STATE_SCAN1);
}

@@ -865,16 +865,16 @@ static void srcu_gp_end(struct srcu_struct *ssp)

/* End the current grace period. */
spin_lock_irq_rcu_node(ssp->srcu_sup);
- idx = rcu_seq_state(ssp->srcu_gp_seq);
+ idx = rcu_seq_state(ssp->srcu_sup->srcu_gp_seq);
WARN_ON_ONCE(idx != SRCU_STATE_SCAN2);
- if (ULONG_CMP_LT(READ_ONCE(ssp->srcu_gp_seq), READ_ONCE(ssp->srcu_gp_seq_needed_exp)))
+ if (ULONG_CMP_LT(READ_ONCE(ssp->srcu_sup->srcu_gp_seq), READ_ONCE(ssp->srcu_sup->srcu_gp_seq_needed_exp)))
cbdelay = 0;

- WRITE_ONCE(ssp->srcu_last_gp_end, ktime_get_mono_fast_ns());
- rcu_seq_end(&ssp->srcu_gp_seq);
- gpseq = rcu_seq_current(&ssp->srcu_gp_seq);
- if (ULONG_CMP_LT(ssp->srcu_gp_seq_needed_exp, gpseq))
- WRITE_ONCE(ssp->srcu_gp_seq_needed_exp, gpseq);
+ WRITE_ONCE(ssp->srcu_sup->srcu_last_gp_end, ktime_get_mono_fast_ns());
+ rcu_seq_end(&ssp->srcu_sup->srcu_gp_seq);
+ gpseq = rcu_seq_current(&ssp->srcu_sup->srcu_gp_seq);
+ if (ULONG_CMP_LT(ssp->srcu_sup->srcu_gp_seq_needed_exp, gpseq))
+ WRITE_ONCE(ssp->srcu_sup->srcu_gp_seq_needed_exp, gpseq);
spin_unlock_irq_rcu_node(ssp->srcu_sup);
mutex_unlock(&ssp->srcu_sup->srcu_gp_mutex);
/* A new grace period can start at this point. But only one. */
@@ -925,9 +925,9 @@ static void srcu_gp_end(struct srcu_struct *ssp)

/* Start a new grace period if needed. */
spin_lock_irq_rcu_node(ssp->srcu_sup);
- gpseq = rcu_seq_current(&ssp->srcu_gp_seq);
+ gpseq = rcu_seq_current(&ssp->srcu_sup->srcu_gp_seq);
if (!rcu_seq_state(gpseq) &&
- ULONG_CMP_LT(gpseq, ssp->srcu_gp_seq_needed)) {
+ ULONG_CMP_LT(gpseq, ssp->srcu_sup->srcu_gp_seq_needed)) {
srcu_gp_start(ssp);
spin_unlock_irq_rcu_node(ssp->srcu_sup);
srcu_reschedule(ssp, 0);
@@ -960,7 +960,7 @@ static void srcu_funnel_exp_start(struct srcu_struct *ssp, struct srcu_node *snp
if (snp)
for (; snp != NULL; snp = snp->srcu_parent) {
sgsne = READ_ONCE(snp->srcu_gp_seq_needed_exp);
- if (WARN_ON_ONCE(rcu_seq_done(&ssp->srcu_gp_seq, s)) ||
+ if (WARN_ON_ONCE(rcu_seq_done(&ssp->srcu_sup->srcu_gp_seq, s)) ||
(!srcu_invl_snp_seq(sgsne) && ULONG_CMP_GE(sgsne, s)))
return;
spin_lock_irqsave_rcu_node(snp, flags);
@@ -973,8 +973,8 @@ static void srcu_funnel_exp_start(struct srcu_struct *ssp, struct srcu_node *snp
spin_unlock_irqrestore_rcu_node(snp, flags);
}
spin_lock_irqsave_ssp_contention(ssp, &flags);
- if (ULONG_CMP_LT(ssp->srcu_gp_seq_needed_exp, s))
- WRITE_ONCE(ssp->srcu_gp_seq_needed_exp, s);
+ if (ULONG_CMP_LT(ssp->srcu_sup->srcu_gp_seq_needed_exp, s))
+ WRITE_ONCE(ssp->srcu_sup->srcu_gp_seq_needed_exp, s);
spin_unlock_irqrestore_rcu_node(ssp->srcu_sup, flags);
}

@@ -1010,7 +1010,7 @@ static void srcu_funnel_gp_start(struct srcu_struct *ssp, struct srcu_data *sdp,
if (snp_leaf)
/* Each pass through the loop does one level of the srcu_node tree. */
for (snp = snp_leaf; snp != NULL; snp = snp->srcu_parent) {
- if (WARN_ON_ONCE(rcu_seq_done(&ssp->srcu_gp_seq, s)) && snp != snp_leaf)
+ if (WARN_ON_ONCE(rcu_seq_done(&ssp->srcu_sup->srcu_gp_seq, s)) && snp != snp_leaf)
return; /* GP already done and CBs recorded. */
spin_lock_irqsave_rcu_node(snp, flags);
snp_seq = snp->srcu_have_cbs[idx];
@@ -1037,20 +1037,20 @@ static void srcu_funnel_gp_start(struct srcu_struct *ssp, struct srcu_data *sdp,

/* Top of tree, must ensure the grace period will be started. */
spin_lock_irqsave_ssp_contention(ssp, &flags);
- if (ULONG_CMP_LT(ssp->srcu_gp_seq_needed, s)) {
+ if (ULONG_CMP_LT(ssp->srcu_sup->srcu_gp_seq_needed, s)) {
/*
* Record need for grace period s. Pair with load
* acquire setting up for initialization.
*/
- smp_store_release(&ssp->srcu_gp_seq_needed, s); /*^^^*/
+ smp_store_release(&ssp->srcu_sup->srcu_gp_seq_needed, s); /*^^^*/
}
- if (!do_norm && ULONG_CMP_LT(ssp->srcu_gp_seq_needed_exp, s))
- WRITE_ONCE(ssp->srcu_gp_seq_needed_exp, s);
+ if (!do_norm && ULONG_CMP_LT(ssp->srcu_sup->srcu_gp_seq_needed_exp, s))
+ WRITE_ONCE(ssp->srcu_sup->srcu_gp_seq_needed_exp, s);

/* If grace period not already in progress, start it. */
- if (!WARN_ON_ONCE(rcu_seq_done(&ssp->srcu_gp_seq, s)) &&
- rcu_seq_state(ssp->srcu_gp_seq) == SRCU_STATE_IDLE) {
- WARN_ON_ONCE(ULONG_CMP_GE(ssp->srcu_gp_seq, ssp->srcu_gp_seq_needed));
+ if (!WARN_ON_ONCE(rcu_seq_done(&ssp->srcu_sup->srcu_gp_seq, s)) &&
+ rcu_seq_state(ssp->srcu_sup->srcu_gp_seq) == SRCU_STATE_IDLE) {
+ WARN_ON_ONCE(ULONG_CMP_GE(ssp->srcu_sup->srcu_gp_seq, ssp->srcu_sup->srcu_gp_seq_needed));
srcu_gp_start(ssp);

// And how can that list_add() in the "else" clause
@@ -1164,18 +1164,18 @@ static bool srcu_might_be_idle(struct srcu_struct *ssp)

/* First, see if enough time has passed since the last GP. */
t = ktime_get_mono_fast_ns();
- tlast = READ_ONCE(ssp->srcu_last_gp_end);
+ tlast = READ_ONCE(ssp->srcu_sup->srcu_last_gp_end);
if (exp_holdoff == 0 ||
time_in_range_open(t, tlast, tlast + exp_holdoff))
return false; /* Too soon after last GP. */

/* Next, check for probable idleness. */
- curseq = rcu_seq_current(&ssp->srcu_gp_seq);
+ curseq = rcu_seq_current(&ssp->srcu_sup->srcu_gp_seq);
smp_mb(); /* Order ->srcu_gp_seq with ->srcu_gp_seq_needed. */
- if (ULONG_CMP_LT(curseq, READ_ONCE(ssp->srcu_gp_seq_needed)))
+ if (ULONG_CMP_LT(curseq, READ_ONCE(ssp->srcu_sup->srcu_gp_seq_needed)))
return false; /* Grace period in progress, so not idle. */
smp_mb(); /* Order ->srcu_gp_seq with prior access. */
- if (curseq != rcu_seq_current(&ssp->srcu_gp_seq))
+ if (curseq != rcu_seq_current(&ssp->srcu_sup->srcu_gp_seq))
return false; /* GP # changed, so not idle. */
return true; /* With reasonable probability, idle! */
}
@@ -1218,8 +1218,8 @@ static unsigned long srcu_gp_start_if_needed(struct srcu_struct *ssp,
if (rhp)
rcu_segcblist_enqueue(&sdp->srcu_cblist, rhp);
rcu_segcblist_advance(&sdp->srcu_cblist,
- rcu_seq_current(&ssp->srcu_gp_seq));
- s = rcu_seq_snap(&ssp->srcu_gp_seq);
+ rcu_seq_current(&ssp->srcu_sup->srcu_gp_seq));
+ s = rcu_seq_snap(&ssp->srcu_sup->srcu_gp_seq);
(void)rcu_segcblist_accelerate(&sdp->srcu_cblist, s);
if (ULONG_CMP_LT(sdp->srcu_gp_seq_needed, s)) {
sdp->srcu_gp_seq_needed = s;
@@ -1430,7 +1430,7 @@ unsigned long get_state_synchronize_srcu(struct srcu_struct *ssp)
// Any prior manipulation of SRCU-protected data must happen
// before the load from ->srcu_gp_seq.
smp_mb();
- return rcu_seq_snap(&ssp->srcu_gp_seq);
+ return rcu_seq_snap(&ssp->srcu_sup->srcu_gp_seq);
}
EXPORT_SYMBOL_GPL(get_state_synchronize_srcu);

@@ -1477,7 +1477,7 @@ EXPORT_SYMBOL_GPL(start_poll_synchronize_srcu);
*/
bool poll_state_synchronize_srcu(struct srcu_struct *ssp, unsigned long cookie)
{
- if (!rcu_seq_done(&ssp->srcu_gp_seq, cookie))
+ if (!rcu_seq_done(&ssp->srcu_sup->srcu_gp_seq, cookie))
return false;
// Ensure that the end of the SRCU grace period happens before
// any subsequent code that the caller might execute.
@@ -1597,16 +1597,16 @@ static void srcu_advance_state(struct srcu_struct *ssp)
* The load-acquire ensures that we see the accesses performed
* by the prior grace period.
*/
- idx = rcu_seq_state(smp_load_acquire(&ssp->srcu_gp_seq)); /* ^^^ */
+ idx = rcu_seq_state(smp_load_acquire(&ssp->srcu_sup->srcu_gp_seq)); /* ^^^ */
if (idx == SRCU_STATE_IDLE) {
spin_lock_irq_rcu_node(ssp->srcu_sup);
- if (ULONG_CMP_GE(ssp->srcu_gp_seq, ssp->srcu_gp_seq_needed)) {
- WARN_ON_ONCE(rcu_seq_state(ssp->srcu_gp_seq));
+ if (ULONG_CMP_GE(ssp->srcu_sup->srcu_gp_seq, ssp->srcu_sup->srcu_gp_seq_needed)) {
+ WARN_ON_ONCE(rcu_seq_state(ssp->srcu_sup->srcu_gp_seq));
spin_unlock_irq_rcu_node(ssp->srcu_sup);
mutex_unlock(&ssp->srcu_sup->srcu_gp_mutex);
return;
}
- idx = rcu_seq_state(READ_ONCE(ssp->srcu_gp_seq));
+ idx = rcu_seq_state(READ_ONCE(ssp->srcu_sup->srcu_gp_seq));
if (idx == SRCU_STATE_IDLE)
srcu_gp_start(ssp);
spin_unlock_irq_rcu_node(ssp->srcu_sup);
@@ -1616,7 +1616,7 @@ static void srcu_advance_state(struct srcu_struct *ssp)
}
}

- if (rcu_seq_state(READ_ONCE(ssp->srcu_gp_seq)) == SRCU_STATE_SCAN1) {
+ if (rcu_seq_state(READ_ONCE(ssp->srcu_sup->srcu_gp_seq)) == SRCU_STATE_SCAN1) {
idx = 1 ^ (ssp->srcu_idx & 1);
if (!try_check_zero(ssp, idx, 1)) {
mutex_unlock(&ssp->srcu_sup->srcu_gp_mutex);
@@ -1624,12 +1624,12 @@ static void srcu_advance_state(struct srcu_struct *ssp)
}
srcu_flip(ssp);
spin_lock_irq_rcu_node(ssp->srcu_sup);
- rcu_seq_set_state(&ssp->srcu_gp_seq, SRCU_STATE_SCAN2);
+ rcu_seq_set_state(&ssp->srcu_sup->srcu_gp_seq, SRCU_STATE_SCAN2);
ssp->srcu_n_exp_nodelay = 0;
spin_unlock_irq_rcu_node(ssp->srcu_sup);
}

- if (rcu_seq_state(READ_ONCE(ssp->srcu_gp_seq)) == SRCU_STATE_SCAN2) {
+ if (rcu_seq_state(READ_ONCE(ssp->srcu_sup->srcu_gp_seq)) == SRCU_STATE_SCAN2) {

/*
* SRCU read-side critical sections are normally short,
@@ -1666,7 +1666,7 @@ static void srcu_invoke_callbacks(struct work_struct *work)
rcu_cblist_init(&ready_cbs);
spin_lock_irq_rcu_node(sdp);
rcu_segcblist_advance(&sdp->srcu_cblist,
- rcu_seq_current(&ssp->srcu_gp_seq));
+ rcu_seq_current(&ssp->srcu_sup->srcu_gp_seq));
if (sdp->srcu_cblist_invoking ||
!rcu_segcblist_ready_cbs(&sdp->srcu_cblist)) {
spin_unlock_irq_rcu_node(sdp);
@@ -1694,7 +1694,7 @@ static void srcu_invoke_callbacks(struct work_struct *work)
spin_lock_irq_rcu_node(sdp);
rcu_segcblist_add_len(&sdp->srcu_cblist, -len);
(void)rcu_segcblist_accelerate(&sdp->srcu_cblist,
- rcu_seq_snap(&ssp->srcu_gp_seq));
+ rcu_seq_snap(&ssp->srcu_sup->srcu_gp_seq));
sdp->srcu_cblist_invoking = false;
more = rcu_segcblist_ready_cbs(&sdp->srcu_cblist);
spin_unlock_irq_rcu_node(sdp);
@@ -1711,12 +1711,12 @@ static void srcu_reschedule(struct srcu_struct *ssp, unsigned long delay)
bool pushgp = true;

spin_lock_irq_rcu_node(ssp->srcu_sup);
- if (ULONG_CMP_GE(ssp->srcu_gp_seq, ssp->srcu_gp_seq_needed)) {
- if (!WARN_ON_ONCE(rcu_seq_state(ssp->srcu_gp_seq))) {
+ if (ULONG_CMP_GE(ssp->srcu_sup->srcu_gp_seq, ssp->srcu_sup->srcu_gp_seq_needed)) {
+ if (!WARN_ON_ONCE(rcu_seq_state(ssp->srcu_sup->srcu_gp_seq))) {
/* All requests fulfilled, time to go idle. */
pushgp = false;
}
- } else if (!rcu_seq_state(ssp->srcu_gp_seq)) {
+ } else if (!rcu_seq_state(ssp->srcu_sup->srcu_gp_seq)) {
/* Outstanding request and no GP. Start one. */
srcu_gp_start(ssp);
}
@@ -1762,7 +1762,7 @@ void srcutorture_get_gp_data(enum rcutorture_type test_type,
if (test_type != SRCU_FLAVOR)
return;
*flags = 0;
- *gp_seq = rcu_seq_current(&ssp->srcu_gp_seq);
+ *gp_seq = rcu_seq_current(&ssp->srcu_sup->srcu_gp_seq);
}
EXPORT_SYMBOL_GPL(srcutorture_get_gp_data);

@@ -1791,7 +1791,7 @@ void srcu_torture_stats_print(struct srcu_struct *ssp, char *tt, char *tf)
if (ss_state < 0 || ss_state >= ARRAY_SIZE(srcu_size_state_name))
ss_state_idx = ARRAY_SIZE(srcu_size_state_name) - 1;
pr_alert("%s%s Tree SRCU g%ld state %d (%s)",
- tt, tf, rcu_seq_current(&ssp->srcu_gp_seq), ss_state,
+ tt, tf, rcu_seq_current(&ssp->srcu_sup->srcu_gp_seq), ss_state,
srcu_size_state_name[ss_state_idx]);
if (!ssp->sda) {
// Called after cleanup_srcu_struct(), perhaps.
@@ -1905,7 +1905,7 @@ static void srcu_module_going(struct module *mod)

for (i = 0; i < mod->num_srcu_structs; i++) {
ssp = *(sspp++);
- if (!rcu_seq_state(smp_load_acquire(&ssp->srcu_gp_seq_needed)) &&
+ if (!rcu_seq_state(smp_load_acquire(&ssp->srcu_sup->srcu_gp_seq_needed)) &&
!WARN_ON_ONCE(!ssp->sda_is_static))
cleanup_srcu_struct(ssp);
free_percpu(ssp->sda);
--
2.40.0.rc2