folio_batch.h

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/* SPDX-License-Identifier: GPL-2.0 */
/*
 * include/linux/folio_batch.h
 *
 * In many places it is efficient to batch an operation up against multiple
 * folios.  A folio_batch is a container which is used for that.
 */
 
#ifndef _LINUX_FOLIO_BATCH_H
#define _LINUX_FOLIO_BATCH_H
 
#include <linux/types.h>
 
/* 31 pointers + header align the folio_batch structure to a power of two */
#define FOLIO_BATCH_SIZE    31
 
struct folio;
 
struct folio_batch {
    unsigned char nr;
    unsigned char i;
    bool percpu_pvec_drained;
    struct folio *folios[FOLIO_BATCH_SIZE];
};
 
static inline void folio_batch_init(struct folio_batch *fbatch)
{
    fbatch->nr = 0;
    fbatch->i = 0;
    fbatch->percpu_pvec_drained = false;
}
 
static inline void folio_batch_reinit(struct folio_batch *fbatch)
{
    fbatch->nr = 0;
    fbatch->i = 0;
}
 
static inline unsigned int folio_batch_count(const struct folio_batch *fbatch)
{
    return fbatch->nr;
}
 
static inline unsigned int folio_batch_space(const struct folio_batch *fbatch)
{
    return FOLIO_BATCH_SIZE - fbatch->nr;
}
 
static inline unsigned folio_batch_add(struct folio_batch *fbatch,
        struct folio *folio)
{
    fbatch->folios[fbatch->nr++] = folio;
    return folio_batch_space(fbatch);
}
 
static inline struct folio *folio_batch_next(struct folio_batch *fbatch)
{
    if (fbatch->i == fbatch->nr)
        return NULL;
    return fbatch->folios[fbatch->i++];
}
 
void __folio_batch_release(struct folio_batch *fbatch);
 
static inline void folio_batch_release(struct folio_batch *fbatch)
{
    if (folio_batch_count(fbatch))
        __folio_batch_release(fbatch);
}
 
void folio_batch_remove_exceptionals(struct folio_batch *fbatch);
#endif /* _LINUX_FOLIO_BATCH_H */