/* SPDX-License-Identifier: GPL-2.0-or-later */ /* Queue of folios definitions * * Copyright (C) 2024 Red Hat, Inc. All Rights Reserved. * Written by David Howells ([email protected]) * * See: * * Documentation/core-api/folio_queue.rst * * for a description of the API. */ #ifndef _LINUX_FOLIO_QUEUE_H #define _LINUX_FOLIO_QUEUE_H #include <linux/pagevec.h> /* * Segment in a queue of running buffers. Each segment can hold a number of * folios and a portion of the queue can be referenced with the ITER_FOLIOQ * iterator. The possibility exists of inserting non-folio elements into the * queue (such as gaps). * * Explicit prev and next pointers are used instead of a list_head to make it * easier to add segments to tail and remove them from the head without the * need for a lock. */ struct folio_queue { … }; /** * folioq_init - Initialise a folio queue segment * @folioq: The segment to initialise * * Initialise a folio queue segment. Note that the folio pointers are * left uninitialised. */ static inline void folioq_init(struct folio_queue *folioq) { … } /** * folioq_nr_slots: Query the capacity of a folio queue segment * @folioq: The segment to query * * Query the number of folios that a particular folio queue segment might hold. * [!] NOTE: This must not be assumed to be the same for every segment! */ static inline unsigned int folioq_nr_slots(const struct folio_queue *folioq) { … } /** * folioq_count: Query the occupancy of a folio queue segment * @folioq: The segment to query * * Query the number of folios that have been added to a folio queue segment. * Note that this is not decreased as folios are removed from a segment. */ static inline unsigned int folioq_count(struct folio_queue *folioq) { … } /** * folioq_full: Query if a folio queue segment is full * @folioq: The segment to query * * Query if a folio queue segment is fully occupied. Note that this does not * change if folios are removed from a segment. */ static inline bool folioq_full(struct folio_queue *folioq) { … } /** * folioq_is_marked: Check first folio mark in a folio queue segment * @folioq: The segment to query * @slot: The slot number of the folio to query * * Determine if the first mark is set for the folio in the specified slot in a * folio queue segment. */ static inline bool folioq_is_marked(const struct folio_queue *folioq, unsigned int slot) { … } /** * folioq_mark: Set the first mark on a folio in a folio queue segment * @folioq: The segment to modify * @slot: The slot number of the folio to modify * * Set the first mark for the folio in the specified slot in a folio queue * segment. */ static inline void folioq_mark(struct folio_queue *folioq, unsigned int slot) { … } /** * folioq_unmark: Clear the first mark on a folio in a folio queue segment * @folioq: The segment to modify * @slot: The slot number of the folio to modify * * Clear the first mark for the folio in the specified slot in a folio queue * segment. */ static inline void folioq_unmark(struct folio_queue *folioq, unsigned int slot) { … } /** * folioq_is_marked2: Check second folio mark in a folio queue segment * @folioq: The segment to query * @slot: The slot number of the folio to query * * Determine if the second mark is set for the folio in the specified slot in a * folio queue segment. */ static inline bool folioq_is_marked2(const struct folio_queue *folioq, unsigned int slot) { … } /** * folioq_mark2: Set the second mark on a folio in a folio queue segment * @folioq: The segment to modify * @slot: The slot number of the folio to modify * * Set the second mark for the folio in the specified slot in a folio queue * segment. */ static inline void folioq_mark2(struct folio_queue *folioq, unsigned int slot) { … } /** * folioq_unmark2: Clear the second mark on a folio in a folio queue segment * @folioq: The segment to modify * @slot: The slot number of the folio to modify * * Clear the second mark for the folio in the specified slot in a folio queue * segment. */ static inline void folioq_unmark2(struct folio_queue *folioq, unsigned int slot) { … } /** * folioq_is_marked3: Check third folio mark in a folio queue segment * @folioq: The segment to query * @slot: The slot number of the folio to query * * Determine if the third mark is set for the folio in the specified slot in a * folio queue segment. */ static inline bool folioq_is_marked3(const struct folio_queue *folioq, unsigned int slot) { … } /** * folioq_mark3: Set the third mark on a folio in a folio queue segment * @folioq: The segment to modify * @slot: The slot number of the folio to modify * * Set the third mark for the folio in the specified slot in a folio queue * segment. */ static inline void folioq_mark3(struct folio_queue *folioq, unsigned int slot) { … } /** * folioq_unmark3: Clear the third mark on a folio in a folio queue segment * @folioq: The segment to modify * @slot: The slot number of the folio to modify * * Clear the third mark for the folio in the specified slot in a folio queue * segment. */ static inline void folioq_unmark3(struct folio_queue *folioq, unsigned int slot) { … } static inline unsigned int __folio_order(struct folio *folio) { … } /** * folioq_append: Add a folio to a folio queue segment * @folioq: The segment to add to * @folio: The folio to add * * Add a folio to the tail of the sequence in a folio queue segment, increasing * the occupancy count and returning the slot number for the folio just added. * The folio size is extracted and stored in the queue and the marks are left * unmodified. * * Note that it's left up to the caller to check that the segment capacity will * not be exceeded and to extend the queue. */ static inline unsigned int folioq_append(struct folio_queue *folioq, struct folio *folio) { … } /** * folioq_append_mark: Add a folio to a folio queue segment * @folioq: The segment to add to * @folio: The folio to add * * Add a folio to the tail of the sequence in a folio queue segment, increasing * the occupancy count and returning the slot number for the folio just added. * The folio size is extracted and stored in the queue, the first mark is set * and and the second and third marks are left unmodified. * * Note that it's left up to the caller to check that the segment capacity will * not be exceeded and to extend the queue. */ static inline unsigned int folioq_append_mark(struct folio_queue *folioq, struct folio *folio) { … } /** * folioq_folio: Get a folio from a folio queue segment * @folioq: The segment to access * @slot: The folio slot to access * * Retrieve the folio in the specified slot from a folio queue segment. Note * that no bounds check is made and if the slot hasn't been added into yet, the * pointer will be undefined. If the slot has been cleared, NULL will be * returned. */ static inline struct folio *folioq_folio(const struct folio_queue *folioq, unsigned int slot) { … } /** * folioq_folio_order: Get the order of a folio from a folio queue segment * @folioq: The segment to access * @slot: The folio slot to access * * Retrieve the order of the folio in the specified slot from a folio queue * segment. Note that no bounds check is made and if the slot hasn't been * added into yet, the order returned will be 0. */ static inline unsigned int folioq_folio_order(const struct folio_queue *folioq, unsigned int slot) { … } /** * folioq_folio_size: Get the size of a folio from a folio queue segment * @folioq: The segment to access * @slot: The folio slot to access * * Retrieve the size of the folio in the specified slot from a folio queue * segment. Note that no bounds check is made and if the slot hasn't been * added into yet, the size returned will be PAGE_SIZE. */ static inline size_t folioq_folio_size(const struct folio_queue *folioq, unsigned int slot) { … } /** * folioq_clear: Clear a folio from a folio queue segment * @folioq: The segment to clear * @slot: The folio slot to clear * * Clear a folio from a sequence in a folio queue segment and clear its marks. * The occupancy count is left unchanged. */ static inline void folioq_clear(struct folio_queue *folioq, unsigned int slot) { … } #endif /* _LINUX_FOLIO_QUEUE_H */
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