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rcu: Remove unused RCU list functions
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Given changes to callback migration, rcu_cblist_head(),
rcu_cblist_tail(), rcu_cblist_count_cbs(), rcu_segcblist_segempty(),
rcu_segcblist_dequeued_lazy(), and rcu_segcblist_new_cbs() are
no longer used.  This commit therefore removes them.

Signed-off-by: Paul E. McKenney <[email protected]>
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@paulmck
paulmck committed Jul 25, 2017
1 parent f2dbe4a commit aed4e04
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Showing 2 changed files with 0 additions and 110 deletions.
84 changes: 0 additions & 84 deletions kernel/rcu/rcu_segcblist.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -35,24 +35,6 @@ void rcu_cblist_init(struct rcu_cblist *rclp)
rclp->len_lazy = 0;
}

/*
* Debug function to actually count the number of callbacks.
* If the number exceeds the limit specified, return -1.
*/
long rcu_cblist_count_cbs(struct rcu_cblist *rclp, long lim)
{
int cnt = 0;
struct rcu_head **rhpp = &rclp->head;

for (;;) {
if (!*rhpp)
return cnt;
if (++cnt > lim)
return -1;
rhpp = &(*rhpp)->next;
}
}

/*
* Dequeue the oldest rcu_head structure from the specified callback
* list. This function assumes that the callback is non-lazy, but
Expand Down Expand Up @@ -102,17 +84,6 @@ void rcu_segcblist_disable(struct rcu_segcblist *rsclp)
rsclp->tails[RCU_NEXT_TAIL] = NULL;
}

/*
* Is the specified segment of the specified rcu_segcblist structure
* empty of callbacks?
*/
bool rcu_segcblist_segempty(struct rcu_segcblist *rsclp, int seg)
{
if (seg == RCU_DONE_TAIL)
return &rsclp->head == rsclp->tails[RCU_DONE_TAIL];
return rsclp->tails[seg - 1] == rsclp->tails[seg];
}

/*
* Does the specified rcu_segcblist structure contain callbacks that
* are ready to be invoked?
Expand All @@ -133,50 +104,6 @@ bool rcu_segcblist_pend_cbs(struct rcu_segcblist *rsclp)
!rcu_segcblist_restempty(rsclp, RCU_DONE_TAIL);
}

/*
* Dequeue and return the first ready-to-invoke callback. If there
* are no ready-to-invoke callbacks, return NULL. Disables interrupts
* to avoid interference. Does not protect from interference from other
* CPUs or tasks.
*/
struct rcu_head *rcu_segcblist_dequeue(struct rcu_segcblist *rsclp)
{
unsigned long flags;
int i;
struct rcu_head *rhp;

local_irq_save(flags);
if (!rcu_segcblist_ready_cbs(rsclp)) {
local_irq_restore(flags);
return NULL;
}
rhp = rsclp->head;
BUG_ON(!rhp);
rsclp->head = rhp->next;
for (i = RCU_DONE_TAIL; i < RCU_CBLIST_NSEGS; i++) {
if (rsclp->tails[i] != &rhp->next)
break;
rsclp->tails[i] = &rsclp->head;
}
smp_mb(); /* Dequeue before decrement for rcu_barrier(). */
WRITE_ONCE(rsclp->len, rsclp->len - 1);
local_irq_restore(flags);
return rhp;
}

/*
* Account for the fact that a previously dequeued callback turned out
* to be marked as lazy.
*/
void rcu_segcblist_dequeued_lazy(struct rcu_segcblist *rsclp)
{
unsigned long flags;

local_irq_save(flags);
rsclp->len_lazy--;
local_irq_restore(flags);
}

/*
* Return a pointer to the first callback in the specified rcu_segcblist
* structure. This is useful for diagnostics.
Expand All @@ -202,17 +129,6 @@ struct rcu_head *rcu_segcblist_first_pend_cb(struct rcu_segcblist *rsclp)
return NULL;
}

/*
* Does the specified rcu_segcblist structure contain callbacks that
* have not yet been processed beyond having been posted, that is,
* does it contain callbacks in its last segment?
*/
bool rcu_segcblist_new_cbs(struct rcu_segcblist *rsclp)
{
return rcu_segcblist_is_enabled(rsclp) &&
!rcu_segcblist_restempty(rsclp, RCU_NEXT_READY_TAIL);
}

/*
* Enqueue the specified callback onto the specified rcu_segcblist
* structure, updating accounting as needed. Note that the ->len
Expand Down
26 changes: 0 additions & 26 deletions kernel/rcu/rcu_segcblist.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -31,29 +31,7 @@ static inline void rcu_cblist_dequeued_lazy(struct rcu_cblist *rclp)
rclp->len_lazy--;
}

/*
* Interim function to return rcu_cblist head pointer. Longer term, the
* rcu_cblist will be used more pervasively, removing the need for this
* function.
*/
static inline struct rcu_head *rcu_cblist_head(struct rcu_cblist *rclp)
{
return rclp->head;
}

/*
* Interim function to return rcu_cblist head pointer. Longer term, the
* rcu_cblist will be used more pervasively, removing the need for this
* function.
*/
static inline struct rcu_head **rcu_cblist_tail(struct rcu_cblist *rclp)
{
WARN_ON_ONCE(!rclp->head);
return rclp->tail;
}

void rcu_cblist_init(struct rcu_cblist *rclp);
long rcu_cblist_count_cbs(struct rcu_cblist *rclp, long lim);
struct rcu_head *rcu_cblist_dequeue(struct rcu_cblist *rclp);

/*
Expand Down Expand Up @@ -134,14 +112,10 @@ static inline struct rcu_head **rcu_segcblist_tail(struct rcu_segcblist *rsclp)

void rcu_segcblist_init(struct rcu_segcblist *rsclp);
void rcu_segcblist_disable(struct rcu_segcblist *rsclp);
bool rcu_segcblist_segempty(struct rcu_segcblist *rsclp, int seg);
bool rcu_segcblist_ready_cbs(struct rcu_segcblist *rsclp);
bool rcu_segcblist_pend_cbs(struct rcu_segcblist *rsclp);
struct rcu_head *rcu_segcblist_dequeue(struct rcu_segcblist *rsclp);
void rcu_segcblist_dequeued_lazy(struct rcu_segcblist *rsclp);
struct rcu_head *rcu_segcblist_first_cb(struct rcu_segcblist *rsclp);
struct rcu_head *rcu_segcblist_first_pend_cb(struct rcu_segcblist *rsclp);
bool rcu_segcblist_new_cbs(struct rcu_segcblist *rsclp);
void rcu_segcblist_enqueue(struct rcu_segcblist *rsclp,
struct rcu_head *rhp, bool lazy);
bool rcu_segcblist_entrain(struct rcu_segcblist *rsclp,
Expand Down

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