/* * RCU segmented callback lists, internal-to-rcu header file * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, you can access it online at * http://www.gnu.org/licenses/gpl-2.0.html. * * Copyright IBM Corporation, 2017 * * Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com> */ #include <linux/rcu_segcblist.h> /* * Account for the fact that a previously dequeued callback turned out * to be marked as lazy. */ static inline void rcu_cblist_dequeued_lazy(struct rcu_cblist *rclp) { rclp->len_lazy--; } void rcu_cblist_init(struct rcu_cblist *rclp); struct rcu_head *rcu_cblist_dequeue(struct rcu_cblist *rclp); /* * Is the specified rcu_segcblist structure empty? * * But careful! The fact that the ->head field is NULL does not * necessarily imply that there are no callbacks associated with * this structure. When callbacks are being invoked, they are * removed as a group. If callback invocation must be preempted, * the remaining callbacks will be added back to the list. Either * way, the counts are updated later. * * So it is often the case that rcu_segcblist_n_cbs() should be used * instead. */ static inline bool rcu_segcblist_empty(struct rcu_segcblist *rsclp) { return !rsclp->head; } /* Return number of callbacks in segmented callback list. */ static inline long rcu_segcblist_n_cbs(struct rcu_segcblist *rsclp) { return READ_ONCE(rsclp->len); } /* Return number of lazy callbacks in segmented callback list. */ static inline long rcu_segcblist_n_lazy_cbs(struct rcu_segcblist *rsclp) { return rsclp->len_lazy; } /* Return number of lazy callbacks in segmented callback list. */ static inline long rcu_segcblist_n_nonlazy_cbs(struct rcu_segcblist *rsclp) { return rsclp->len - rsclp->len_lazy; } /* * Is the specified rcu_segcblist enabled, for example, not corresponding * to an offline or callback-offloaded CPU? */ static inline bool rcu_segcblist_is_enabled(struct rcu_segcblist *rsclp) { return !!rsclp->tails[RCU_NEXT_TAIL]; } /* * Are all segments following the specified segment of the specified * rcu_segcblist structure empty of callbacks? (The specified * segment might well contain callbacks.) */ static inline bool rcu_segcblist_restempty(struct rcu_segcblist *rsclp, int seg) { return !*rsclp->tails[seg]; } /* * Interim function to return rcu_segcblist head pointer. Longer term, the * rcu_segcblist will be used more pervasively, removing the need for this * function. */ static inline struct rcu_head *rcu_segcblist_head(struct rcu_segcblist *rsclp) { return rsclp->head; } /* * Interim function to return rcu_segcblist head pointer. Longer term, the * rcu_segcblist will be used more pervasively, removing the need for this * function. */ static inline struct rcu_head **rcu_segcblist_tail(struct rcu_segcblist *rsclp) { WARN_ON_ONCE(rcu_segcblist_empty(rsclp)); return rsclp->tails[RCU_NEXT_TAIL]; } void rcu_segcblist_init(struct rcu_segcblist *rsclp); void rcu_segcblist_disable(struct rcu_segcblist *rsclp); bool rcu_segcblist_ready_cbs(struct rcu_segcblist *rsclp); bool rcu_segcblist_pend_cbs(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); void rcu_segcblist_enqueue(struct rcu_segcblist *rsclp, struct rcu_head *rhp, bool lazy); bool rcu_segcblist_entrain(struct rcu_segcblist *rsclp, struct rcu_head *rhp, bool lazy); void rcu_segcblist_extract_count(struct rcu_segcblist *rsclp, struct rcu_cblist *rclp); void rcu_segcblist_extract_done_cbs(struct rcu_segcblist *rsclp, struct rcu_cblist *rclp); void rcu_segcblist_extract_pend_cbs(struct rcu_segcblist *rsclp, struct rcu_cblist *rclp); void rcu_segcblist_insert_count(struct rcu_segcblist *rsclp, struct rcu_cblist *rclp); void rcu_segcblist_insert_done_cbs(struct rcu_segcblist *rsclp, struct rcu_cblist *rclp); void rcu_segcblist_insert_pend_cbs(struct rcu_segcblist *rsclp, struct rcu_cblist *rclp); void rcu_segcblist_advance(struct rcu_segcblist *rsclp, unsigned long seq); bool rcu_segcblist_accelerate(struct rcu_segcblist *rsclp, unsigned long seq); void rcu_segcblist_merge(struct rcu_segcblist *dst_rsclp, struct rcu_segcblist *src_rsclp);