Commit aacb5d91 authored by Paul E. McKenney's avatar Paul E. McKenney

srcu: Use "ssp" instead of "sp" for srcu_struct pointer

In RCU, the distinction between "rsp", "rnp", and "rdp" has served well
for a great many years, but in SRCU, "sp" vs. "sdp" has proven confusing.
This commit therefore renames SRCU's "sp" pointers to "ssp", so that there
is "ssp" for srcu_struct pointer, "snp" for srcu_node pointer, and "sdp"
for srcu_data pointer.
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.ibm.com>
parent eb4c2382
......@@ -38,20 +38,20 @@ struct srcu_struct;
#ifdef CONFIG_DEBUG_LOCK_ALLOC
int __init_srcu_struct(struct srcu_struct *sp, const char *name,
int __init_srcu_struct(struct srcu_struct *ssp, const char *name,
struct lock_class_key *key);
#define init_srcu_struct(sp) \
#define init_srcu_struct(ssp) \
({ \
static struct lock_class_key __srcu_key; \
\
__init_srcu_struct((sp), #sp, &__srcu_key); \
__init_srcu_struct((ssp), #ssp, &__srcu_key); \
})
#define __SRCU_DEP_MAP_INIT(srcu_name) .dep_map = { .name = #srcu_name },
#else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
int init_srcu_struct(struct srcu_struct *sp);
int init_srcu_struct(struct srcu_struct *ssp);
#define __SRCU_DEP_MAP_INIT(srcu_name)
#endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */
......@@ -67,28 +67,28 @@ int init_srcu_struct(struct srcu_struct *sp);
struct srcu_struct { };
#endif
void call_srcu(struct srcu_struct *sp, struct rcu_head *head,
void call_srcu(struct srcu_struct *ssp, struct rcu_head *head,
void (*func)(struct rcu_head *head));
void _cleanup_srcu_struct(struct srcu_struct *sp, bool quiesced);
int __srcu_read_lock(struct srcu_struct *sp) __acquires(sp);
void __srcu_read_unlock(struct srcu_struct *sp, int idx) __releases(sp);
void synchronize_srcu(struct srcu_struct *sp);
void _cleanup_srcu_struct(struct srcu_struct *ssp, bool quiesced);
int __srcu_read_lock(struct srcu_struct *ssp) __acquires(ssp);
void __srcu_read_unlock(struct srcu_struct *ssp, int idx) __releases(ssp);
void synchronize_srcu(struct srcu_struct *ssp);
/**
* cleanup_srcu_struct - deconstruct a sleep-RCU structure
* @sp: structure to clean up.
* @ssp: structure to clean up.
*
* Must invoke this after you are finished using a given srcu_struct that
* was initialized via init_srcu_struct(), else you leak memory.
*/
static inline void cleanup_srcu_struct(struct srcu_struct *sp)
static inline void cleanup_srcu_struct(struct srcu_struct *ssp)
{
_cleanup_srcu_struct(sp, false);
_cleanup_srcu_struct(ssp, false);
}
/**
* cleanup_srcu_struct_quiesced - deconstruct a quiesced sleep-RCU structure
* @sp: structure to clean up.
* @ssp: structure to clean up.
*
* Must invoke this after you are finished using a given srcu_struct that
* was initialized via init_srcu_struct(), else you leak memory. Also,
......@@ -103,16 +103,16 @@ static inline void cleanup_srcu_struct(struct srcu_struct *sp)
* (with high probability, anyway), and will also cause the srcu_struct
* to be leaked.
*/
static inline void cleanup_srcu_struct_quiesced(struct srcu_struct *sp)
static inline void cleanup_srcu_struct_quiesced(struct srcu_struct *ssp)
{
_cleanup_srcu_struct(sp, true);
_cleanup_srcu_struct(ssp, true);
}
#ifdef CONFIG_DEBUG_LOCK_ALLOC
/**
* srcu_read_lock_held - might we be in SRCU read-side critical section?
* @sp: The srcu_struct structure to check
* @ssp: The srcu_struct structure to check
*
* If CONFIG_DEBUG_LOCK_ALLOC is selected, returns nonzero iff in an SRCU
* read-side critical section. In absence of CONFIG_DEBUG_LOCK_ALLOC,
......@@ -126,16 +126,16 @@ static inline void cleanup_srcu_struct_quiesced(struct srcu_struct *sp)
* relies on normal RCU, it can be called from the CPU which
* is in the idle loop from an RCU point of view or offline.
*/
static inline int srcu_read_lock_held(const struct srcu_struct *sp)
static inline int srcu_read_lock_held(const struct srcu_struct *ssp)
{
if (!debug_lockdep_rcu_enabled())
return 1;
return lock_is_held(&sp->dep_map);
return lock_is_held(&ssp->dep_map);
}
#else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
static inline int srcu_read_lock_held(const struct srcu_struct *sp)
static inline int srcu_read_lock_held(const struct srcu_struct *ssp)
{
return 1;
}
......@@ -145,7 +145,7 @@ static inline int srcu_read_lock_held(const struct srcu_struct *sp)
/**
* srcu_dereference_check - fetch SRCU-protected pointer for later dereferencing
* @p: the pointer to fetch and protect for later dereferencing
* @sp: pointer to the srcu_struct, which is used to check that we
* @ssp: pointer to the srcu_struct, which is used to check that we
* really are in an SRCU read-side critical section.
* @c: condition to check for update-side use
*
......@@ -154,32 +154,32 @@ static inline int srcu_read_lock_held(const struct srcu_struct *sp)
* to 1. The @c argument will normally be a logical expression containing
* lockdep_is_held() calls.
*/
#define srcu_dereference_check(p, sp, c) \
__rcu_dereference_check((p), (c) || srcu_read_lock_held(sp), __rcu)
#define srcu_dereference_check(p, ssp, c) \
__rcu_dereference_check((p), (c) || srcu_read_lock_held(ssp), __rcu)
/**
* srcu_dereference - fetch SRCU-protected pointer for later dereferencing
* @p: the pointer to fetch and protect for later dereferencing
* @sp: pointer to the srcu_struct, which is used to check that we
* @ssp: pointer to the srcu_struct, which is used to check that we
* really are in an SRCU read-side critical section.
*
* Makes rcu_dereference_check() do the dirty work. If PROVE_RCU
* is enabled, invoking this outside of an RCU read-side critical
* section will result in an RCU-lockdep splat.
*/
#define srcu_dereference(p, sp) srcu_dereference_check((p), (sp), 0)
#define srcu_dereference(p, ssp) srcu_dereference_check((p), (ssp), 0)
/**
* srcu_dereference_notrace - no tracing and no lockdep calls from here
* @p: the pointer to fetch and protect for later dereferencing
* @sp: pointer to the srcu_struct, which is used to check that we
* @ssp: pointer to the srcu_struct, which is used to check that we
* really are in an SRCU read-side critical section.
*/
#define srcu_dereference_notrace(p, sp) srcu_dereference_check((p), (sp), 1)
#define srcu_dereference_notrace(p, ssp) srcu_dereference_check((p), (ssp), 1)
/**
* srcu_read_lock - register a new reader for an SRCU-protected structure.
* @sp: srcu_struct in which to register the new reader.
* @ssp: srcu_struct in which to register the new reader.
*
* Enter an SRCU read-side critical section. Note that SRCU read-side
* critical sections may be nested. However, it is illegal to
......@@ -194,44 +194,44 @@ static inline int srcu_read_lock_held(const struct srcu_struct *sp)
* srcu_read_unlock() in an irq handler if the matching srcu_read_lock()
* was invoked in process context.
*/
static inline int srcu_read_lock(struct srcu_struct *sp) __acquires(sp)
static inline int srcu_read_lock(struct srcu_struct *ssp) __acquires(ssp)
{
int retval;
retval = __srcu_read_lock(sp);
rcu_lock_acquire(&(sp)->dep_map);
retval = __srcu_read_lock(ssp);
rcu_lock_acquire(&(ssp)->dep_map);
return retval;
}
/* Used by tracing, cannot be traced and cannot invoke lockdep. */
static inline notrace int
srcu_read_lock_notrace(struct srcu_struct *sp) __acquires(sp)
srcu_read_lock_notrace(struct srcu_struct *ssp) __acquires(ssp)
{
int retval;
retval = __srcu_read_lock(sp);
retval = __srcu_read_lock(ssp);
return retval;
}
/**
* srcu_read_unlock - unregister a old reader from an SRCU-protected structure.
* @sp: srcu_struct in which to unregister the old reader.
* @ssp: srcu_struct in which to unregister the old reader.
* @idx: return value from corresponding srcu_read_lock().
*
* Exit an SRCU read-side critical section.
*/
static inline void srcu_read_unlock(struct srcu_struct *sp, int idx)
__releases(sp)
static inline void srcu_read_unlock(struct srcu_struct *ssp, int idx)
__releases(ssp)
{
rcu_lock_release(&(sp)->dep_map);
__srcu_read_unlock(sp, idx);
rcu_lock_release(&(ssp)->dep_map);
__srcu_read_unlock(ssp, idx);
}
/* Used by tracing, cannot be traced and cannot call lockdep. */
static inline notrace void
srcu_read_unlock_notrace(struct srcu_struct *sp, int idx) __releases(sp)
srcu_read_unlock_notrace(struct srcu_struct *ssp, int idx) __releases(ssp)
{
__srcu_read_unlock(sp, idx);
__srcu_read_unlock(ssp, idx);
}
/**
......
......@@ -60,7 +60,7 @@ void srcu_drive_gp(struct work_struct *wp);
#define DEFINE_STATIC_SRCU(name) \
static struct srcu_struct name = __SRCU_STRUCT_INIT(name, name)
void synchronize_srcu(struct srcu_struct *sp);
void synchronize_srcu(struct srcu_struct *ssp);
/*
* Counts the new reader in the appropriate per-CPU element of the
......@@ -68,36 +68,36 @@ void synchronize_srcu(struct srcu_struct *sp);
* __srcu_read_unlock() must be in the same handler instance. Returns an
* index that must be passed to the matching srcu_read_unlock().
*/
static inline int __srcu_read_lock(struct srcu_struct *sp)
static inline int __srcu_read_lock(struct srcu_struct *ssp)
{
int idx;
idx = READ_ONCE(sp->srcu_idx);
WRITE_ONCE(sp->srcu_lock_nesting[idx], sp->srcu_lock_nesting[idx] + 1);
idx = READ_ONCE(ssp->srcu_idx);
WRITE_ONCE(ssp->srcu_lock_nesting[idx], ssp->srcu_lock_nesting[idx] + 1);
return idx;
}
static inline void synchronize_srcu_expedited(struct srcu_struct *sp)
static inline void synchronize_srcu_expedited(struct srcu_struct *ssp)
{
synchronize_srcu(sp);
synchronize_srcu(ssp);
}
static inline void srcu_barrier(struct srcu_struct *sp)
static inline void srcu_barrier(struct srcu_struct *ssp)
{
synchronize_srcu(sp);
synchronize_srcu(ssp);
}
/* Defined here to avoid size increase for non-torture kernels. */
static inline void srcu_torture_stats_print(struct srcu_struct *sp,
static inline void srcu_torture_stats_print(struct srcu_struct *ssp,
char *tt, char *tf)
{
int idx;
idx = READ_ONCE(sp->srcu_idx) & 0x1;
idx = READ_ONCE(ssp->srcu_idx) & 0x1;
pr_alert("%s%s Tiny SRCU per-CPU(idx=%d): (%hd,%hd)\n",
tt, tf, idx,
READ_ONCE(sp->srcu_lock_nesting[!idx]),
READ_ONCE(sp->srcu_lock_nesting[idx]));
READ_ONCE(ssp->srcu_lock_nesting[!idx]),
READ_ONCE(ssp->srcu_lock_nesting[idx]));
}
#endif
......@@ -51,7 +51,7 @@ struct srcu_data {
unsigned long grpmask; /* Mask for leaf srcu_node */
/* ->srcu_data_have_cbs[]. */
int cpu;
struct srcu_struct *sp;
struct srcu_struct *ssp;
};
/*
......@@ -138,8 +138,8 @@ struct srcu_struct {
#define DEFINE_SRCU(name) __DEFINE_SRCU(name, /* not static */)
#define DEFINE_STATIC_SRCU(name) __DEFINE_SRCU(name, static)
void synchronize_srcu_expedited(struct srcu_struct *sp);
void srcu_barrier(struct srcu_struct *sp);
void srcu_torture_stats_print(struct srcu_struct *sp, char *tt, char *tf);
void synchronize_srcu_expedited(struct srcu_struct *ssp);
void srcu_barrier(struct srcu_struct *ssp);
void srcu_torture_stats_print(struct srcu_struct *ssp, char *tt, char *tf);
#endif
......@@ -37,30 +37,30 @@ int rcu_scheduler_active __read_mostly;
static LIST_HEAD(srcu_boot_list);
static bool srcu_init_done;
static int init_srcu_struct_fields(struct srcu_struct *sp)
static int init_srcu_struct_fields(struct srcu_struct *ssp)
{
sp->srcu_lock_nesting[0] = 0;
sp->srcu_lock_nesting[1] = 0;
init_swait_queue_head(&sp->srcu_wq);
sp->srcu_cb_head = NULL;
sp->srcu_cb_tail = &sp->srcu_cb_head;
sp->srcu_gp_running = false;
sp->srcu_gp_waiting = false;
sp->srcu_idx = 0;
INIT_WORK(&sp->srcu_work, srcu_drive_gp);
INIT_LIST_HEAD(&sp->srcu_work.entry);
ssp->srcu_lock_nesting[0] = 0;
ssp->srcu_lock_nesting[1] = 0;
init_swait_queue_head(&ssp->srcu_wq);
ssp->srcu_cb_head = NULL;
ssp->srcu_cb_tail = &ssp->srcu_cb_head;
ssp->srcu_gp_running = false;
ssp->srcu_gp_waiting = false;
ssp->srcu_idx = 0;
INIT_WORK(&ssp->srcu_work, srcu_drive_gp);
INIT_LIST_HEAD(&ssp->srcu_work.entry);
return 0;
}
#ifdef CONFIG_DEBUG_LOCK_ALLOC
int __init_srcu_struct(struct srcu_struct *sp, const char *name,
int __init_srcu_struct(struct srcu_struct *ssp, const char *name,
struct lock_class_key *key)
{
/* Don't re-initialize a lock while it is held. */
debug_check_no_locks_freed((void *)sp, sizeof(*sp));
lockdep_init_map(&sp->dep_map, name, key, 0);
return init_srcu_struct_fields(sp);
debug_check_no_locks_freed((void *)ssp, sizeof(*ssp));
lockdep_init_map(&ssp->dep_map, name, key, 0);
return init_srcu_struct_fields(ssp);
}
EXPORT_SYMBOL_GPL(__init_srcu_struct);
......@@ -68,15 +68,15 @@ EXPORT_SYMBOL_GPL(__init_srcu_struct);
/*
* init_srcu_struct - initialize a sleep-RCU structure
* @sp: structure to initialize.
* @ssp: structure to initialize.
*
* Must invoke this on a given srcu_struct before passing that srcu_struct
* to any other function. Each srcu_struct represents a separate domain
* of SRCU protection.
*/
int init_srcu_struct(struct srcu_struct *sp)
int init_srcu_struct(struct srcu_struct *ssp)
{
return init_srcu_struct_fields(sp);
return init_srcu_struct_fields(ssp);
}
EXPORT_SYMBOL_GPL(init_srcu_struct);
......@@ -84,22 +84,22 @@ EXPORT_SYMBOL_GPL(init_srcu_struct);
/*
* cleanup_srcu_struct - deconstruct a sleep-RCU structure
* @sp: structure to clean up.
* @ssp: structure to clean up.
*
* Must invoke this after you are finished using a given srcu_struct that
* was initialized via init_srcu_struct(), else you leak memory.
*/
void _cleanup_srcu_struct(struct srcu_struct *sp, bool quiesced)
void _cleanup_srcu_struct(struct srcu_struct *ssp, bool quiesced)
{
WARN_ON(sp->srcu_lock_nesting[0] || sp->srcu_lock_nesting[1]);
WARN_ON(ssp->srcu_lock_nesting[0] || ssp->srcu_lock_nesting[1]);
if (quiesced)
WARN_ON(work_pending(&sp->srcu_work));
WARN_ON(work_pending(&ssp->srcu_work));
else
flush_work(&sp->srcu_work);
WARN_ON(sp->srcu_gp_running);
WARN_ON(sp->srcu_gp_waiting);
WARN_ON(sp->srcu_cb_head);
WARN_ON(&sp->srcu_cb_head != sp->srcu_cb_tail);
flush_work(&ssp->srcu_work);
WARN_ON(ssp->srcu_gp_running);
WARN_ON(ssp->srcu_gp_waiting);
WARN_ON(ssp->srcu_cb_head);
WARN_ON(&ssp->srcu_cb_head != ssp->srcu_cb_tail);
}
EXPORT_SYMBOL_GPL(_cleanup_srcu_struct);
......@@ -107,13 +107,13 @@ EXPORT_SYMBOL_GPL(_cleanup_srcu_struct);
* Removes the count for the old reader from the appropriate element of
* the srcu_struct.
*/
void __srcu_read_unlock(struct srcu_struct *sp, int idx)
void __srcu_read_unlock(struct srcu_struct *ssp, int idx)
{
int newval = sp->srcu_lock_nesting[idx] - 1;
int newval = ssp->srcu_lock_nesting[idx] - 1;
WRITE_ONCE(sp->srcu_lock_nesting[idx], newval);
if (!newval && READ_ONCE(sp->srcu_gp_waiting))
swake_up_one(&sp->srcu_wq);
WRITE_ONCE(ssp->srcu_lock_nesting[idx], newval);
if (!newval && READ_ONCE(ssp->srcu_gp_waiting))
swake_up_one(&ssp->srcu_wq);
}
EXPORT_SYMBOL_GPL(__srcu_read_unlock);
......@@ -127,24 +127,24 @@ void srcu_drive_gp(struct work_struct *wp)
int idx;
struct rcu_head *lh;
struct rcu_head *rhp;
struct srcu_struct *sp;
struct srcu_struct *ssp;
sp = container_of(wp, struct srcu_struct, srcu_work);
if (sp->srcu_gp_running || !READ_ONCE(sp->srcu_cb_head))
ssp = container_of(wp, struct srcu_struct, srcu_work);
if (ssp->srcu_gp_running || !READ_ONCE(ssp->srcu_cb_head))
return; /* Already running or nothing to do. */
/* Remove recently arrived callbacks and wait for readers. */
WRITE_ONCE(sp->srcu_gp_running, true);
WRITE_ONCE(ssp->srcu_gp_running, true);
local_irq_disable();
lh = sp->srcu_cb_head;
sp->srcu_cb_head = NULL;
sp->srcu_cb_tail = &sp->srcu_cb_head;
lh = ssp->srcu_cb_head;
ssp->srcu_cb_head = NULL;
ssp->srcu_cb_tail = &ssp->srcu_cb_head;
local_irq_enable();
idx = sp->srcu_idx;
WRITE_ONCE(sp->srcu_idx, !sp->srcu_idx);
WRITE_ONCE(sp->srcu_gp_waiting, true); /* srcu_read_unlock() wakes! */
swait_event_exclusive(sp->srcu_wq, !READ_ONCE(sp->srcu_lock_nesting[idx]));
WRITE_ONCE(sp->srcu_gp_waiting, false); /* srcu_read_unlock() cheap. */
idx = ssp->srcu_idx;
WRITE_ONCE(ssp->srcu_idx, !ssp->srcu_idx);
WRITE_ONCE(ssp->srcu_gp_waiting, true); /* srcu_read_unlock() wakes! */
swait_event_exclusive(ssp->srcu_wq, !READ_ONCE(ssp->srcu_lock_nesting[idx]));
WRITE_ONCE(ssp->srcu_gp_waiting, false); /* srcu_read_unlock() cheap. */
/* Invoke the callbacks we removed above. */
while (lh) {
......@@ -161,9 +161,9 @@ void srcu_drive_gp(struct work_struct *wp)
* at interrupt level, but the ->srcu_gp_running checks will
* straighten that out.
*/
WRITE_ONCE(sp->srcu_gp_running, false);
if (READ_ONCE(sp->srcu_cb_head))
schedule_work(&sp->srcu_work);
WRITE_ONCE(ssp->srcu_gp_running, false);
if (READ_ONCE(ssp->srcu_cb_head))
schedule_work(&ssp->srcu_work);
}
EXPORT_SYMBOL_GPL(srcu_drive_gp);
......@@ -171,7 +171,7 @@ EXPORT_SYMBOL_GPL(srcu_drive_gp);
* Enqueue an SRCU callback on the specified srcu_struct structure,
* initiating grace-period processing if it is not already running.
*/
void call_srcu(struct srcu_struct *sp, struct rcu_head *rhp,
void call_srcu(struct srcu_struct *ssp, struct rcu_head *rhp,
rcu_callback_t func)
{
unsigned long flags;
......@@ -179,14 +179,14 @@ void call_srcu(struct srcu_struct *sp, struct rcu_head *rhp,
rhp->func = func;
rhp->next = NULL;
local_irq_save(flags);
*sp->srcu_cb_tail = rhp;
sp->srcu_cb_tail = &rhp->next;
*ssp->srcu_cb_tail = rhp;
ssp->srcu_cb_tail = &rhp->next;
local_irq_restore(flags);
if (!READ_ONCE(sp->srcu_gp_running)) {
if (!READ_ONCE(ssp->srcu_gp_running)) {
if (likely(srcu_init_done))
schedule_work(&sp->srcu_work);
else if (list_empty(&sp->srcu_work.entry))
list_add(&sp->srcu_work.entry, &srcu_boot_list);
schedule_work(&ssp->srcu_work);
else if (list_empty(&ssp->srcu_work.entry))
list_add(&ssp->srcu_work.entry, &srcu_boot_list);
}
}
EXPORT_SYMBOL_GPL(call_srcu);
......@@ -194,13 +194,13 @@ EXPORT_SYMBOL_GPL(call_srcu);
/*
* synchronize_srcu - wait for prior SRCU read-side critical-section completion
*/
void synchronize_srcu(struct srcu_struct *sp)
void synchronize_srcu(struct srcu_struct *ssp)
{
struct rcu_synchronize rs;
init_rcu_head_on_stack(&rs.head);
init_completion(&rs.completion);
call_srcu(sp, &rs.head, wakeme_after_rcu);
call_srcu(ssp, &rs.head, wakeme_after_rcu);
wait_for_completion(&rs.completion);
destroy_rcu_head_on_stack(&rs.head);
}
......@@ -219,13 +219,13 @@ void __init rcu_scheduler_starting(void)
*/
void __init srcu_init(void)
{
struct srcu_struct *sp;
struct srcu_struct *ssp;
srcu_init_done = true;
while (!list_empty(&srcu_boot_list)) {
sp = list_first_entry(&srcu_boot_list,
ssp = list_first_entry(&srcu_boot_list,
struct srcu_struct, srcu_work.entry);
list_del_init(&sp->srcu_work.entry);
schedule_work(&sp->srcu_work);
list_del_init(&ssp->srcu_work.entry);
schedule_work(&ssp->srcu_work);
}
}
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