kfifo.h

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/*
 * A generic kernel FIFO implementation
 *
 * Copyright (C) 2009/2010 Stefani Seibold <[email protected]>
 *
 * 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, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 */

#ifndef _LINUX_KFIFO_H
#define _LINUX_KFIFO_H

/*
 * How to porting drivers to the new generic FIFO API:
 *
 * - Modify the declaration of the "struct kfifo *" object into a
 *   in-place "struct kfifo" object
 * - Init the in-place object with kfifo_alloc() or kfifo_init()
 *   Note: The address of the in-place "struct kfifo" object must be
 *   passed as the first argument to this functions
 * - Replace the use of __kfifo_put into kfifo_in and __kfifo_get
 *   into kfifo_out
 * - Replace the use of kfifo_put into kfifo_in_spinlocked and kfifo_get
 *   into kfifo_out_spinlocked
 *   Note: the spinlock pointer formerly passed to kfifo_init/kfifo_alloc
 *   must be passed now to the kfifo_in_spinlocked and kfifo_out_spinlocked
 *   as the last parameter
 * - The formerly __kfifo_* functions are renamed into kfifo_*
 */

/*
 * Note about locking : There is no locking required until only * one reader
 * and one writer is using the fifo and no kfifo_reset() will be * called
 *  kfifo_reset_out() can be safely used, until it will be only called
 * in the reader thread.
 *  For multiple writer and one reader there is only a need to lock the writer.
 * And vice versa for only one writer and multiple reader there is only a need
 * to lock the reader.
 */

#include <linux/kernel.h>
#include <linux/spinlock.h>
#include <linux/stddef.h>
#include <linux/scatterlist.h>

struct __kfifo {
    unsigned int    in;
    unsigned int    out;
    unsigned int    mask;
    unsigned int    esize;
    void        *data;
};

#define __STRUCT_KFIFO_COMMON(datatype, recsize, ptrtype) \
    union { \
        struct __kfifo  kfifo; \
        datatype    *type; \
        char        (*rectype)[recsize]; \
        ptrtype     *ptr; \
        const ptrtype   *ptr_const; \
    }

#define __STRUCT_KFIFO(type, size, recsize, ptrtype) \
{ \
    __STRUCT_KFIFO_COMMON(type, recsize, ptrtype); \
    type        buf[((size < 2) || (size & (size - 1))) ? -1 : size]; \
}

#define STRUCT_KFIFO(type, size) \
    struct __STRUCT_KFIFO(type, size, 0, type)

#define __STRUCT_KFIFO_PTR(type, recsize, ptrtype) \
{ \
    __STRUCT_KFIFO_COMMON(type, recsize, ptrtype); \
    type        buf[0]; \
}

#define STRUCT_KFIFO_PTR(type) \
    struct __STRUCT_KFIFO_PTR(type, 0, type)

/*
 * define compatibility "struct kfifo" for dynamic allocated fifos
 */
struct kfifo __STRUCT_KFIFO_PTR(unsigned char, 0, void);

#define STRUCT_KFIFO_REC_1(size) \
    struct __STRUCT_KFIFO(unsigned char, size, 1, void)

#define STRUCT_KFIFO_REC_2(size) \
    struct __STRUCT_KFIFO(unsigned char, size, 2, void)

/*
 * define kfifo_rec types
 */
struct kfifo_rec_ptr_1 __STRUCT_KFIFO_PTR(unsigned char, 1, void);
struct kfifo_rec_ptr_2 __STRUCT_KFIFO_PTR(unsigned char, 2, void);

/*
 * helper macro to distinguish between real in place fifo where the fifo
 * array is a part of the structure and the fifo type where the array is
 * outside of the fifo structure.
 */
#define __is_kfifo_ptr(fifo)    (sizeof(*fifo) == sizeof(struct __kfifo))

#define DECLARE_KFIFO_PTR(fifo, type)   STRUCT_KFIFO_PTR(type) fifo

#define DECLARE_KFIFO(fifo, type, size) STRUCT_KFIFO(type, size) fifo

#define INIT_KFIFO(fifo) \
(void)({ \
    typeof(&(fifo)) __tmp = &(fifo); \
    struct __kfifo *__kfifo = &__tmp->kfifo; \
    __kfifo->in = 0; \
    __kfifo->out = 0; \
    __kfifo->mask = __is_kfifo_ptr(__tmp) ? 0 : ARRAY_SIZE(__tmp->buf) - 1;\
    __kfifo->esize = sizeof(*__tmp->buf); \
    __kfifo->data = __is_kfifo_ptr(__tmp) ?  NULL : __tmp->buf; \
})

#define DEFINE_KFIFO(fifo, type, size) \
    DECLARE_KFIFO(fifo, type, size) = \
    (typeof(fifo)) { \
        { \
            { \
            .in = 0, \
            .out    = 0, \
            .mask   = __is_kfifo_ptr(&(fifo)) ? \
                  0 : \
                  ARRAY_SIZE((fifo).buf) - 1, \
            .esize  = sizeof(*(fifo).buf), \
            .data   = __is_kfifo_ptr(&(fifo)) ? \
                NULL : \
                (fifo).buf, \
            } \
        } \
    }


static inline unsigned int __must_check
__kfifo_uint_must_check_helper(unsigned int val)
{
    return val;
}

static inline int __must_check
__kfifo_int_must_check_helper(int val)
{
    return val;
}

#define kfifo_initialized(fifo) ((fifo)->kfifo.mask)

#define kfifo_esize(fifo)   ((fifo)->kfifo.esize)

#define kfifo_recsize(fifo) (sizeof(*(fifo)->rectype))

#define kfifo_size(fifo)    ((fifo)->kfifo.mask + 1)

#define kfifo_reset(fifo) \
(void)({ \
    typeof((fifo) + 1) __tmp = (fifo); \
    __tmp->kfifo.in = __tmp->kfifo.out = 0; \
})

#define kfifo_reset_out(fifo)   \
(void)({ \
    typeof((fifo) + 1) __tmp = (fifo); \
    __tmp->kfifo.out = __tmp->kfifo.in; \
})

#define kfifo_len(fifo) \
({ \
    typeof((fifo) + 1) __tmpl = (fifo); \
    __tmpl->kfifo.in - __tmpl->kfifo.out; \
})

#define kfifo_is_empty(fifo) \
({ \
    typeof((fifo) + 1) __tmpq = (fifo); \
    __tmpq->kfifo.in == __tmpq->kfifo.out; \
})

#define kfifo_is_full(fifo) \
({ \
    typeof((fifo) + 1) __tmpq = (fifo); \
    kfifo_len(__tmpq) > __tmpq->kfifo.mask; \
})

#define kfifo_avail(fifo) \
__kfifo_uint_must_check_helper( \
({ \
    typeof((fifo) + 1) __tmpq = (fifo); \
    const size_t __recsize = sizeof(*__tmpq->rectype); \
    unsigned int __avail = kfifo_size(__tmpq) - kfifo_len(__tmpq); \
    (__recsize) ? ((__avail <= __recsize) ? 0 : \
    __kfifo_max_r(__avail - __recsize, __recsize)) : \
    __avail; \
}) \
)

#define kfifo_skip(fifo) \
(void)({ \
    typeof((fifo) + 1) __tmp = (fifo); \
    const size_t __recsize = sizeof(*__tmp->rectype); \
    struct __kfifo *__kfifo = &__tmp->kfifo; \
    if (__recsize) \
        __kfifo_skip_r(__kfifo, __recsize); \
    else \
        __kfifo->out++; \
})

#define kfifo_peek_len(fifo) \
__kfifo_uint_must_check_helper( \
({ \
    typeof((fifo) + 1) __tmp = (fifo); \
    const size_t __recsize = sizeof(*__tmp->rectype); \
    struct __kfifo *__kfifo = &__tmp->kfifo; \
    (!__recsize) ? kfifo_len(__tmp) * sizeof(*__tmp->type) : \
    __kfifo_len_r(__kfifo, __recsize); \
}) \
)

#define kfifo_alloc(fifo, size, gfp_mask) \
__kfifo_int_must_check_helper( \
({ \
    typeof((fifo) + 1) __tmp = (fifo); \
    struct __kfifo *__kfifo = &__tmp->kfifo; \
    __is_kfifo_ptr(__tmp) ? \
    __kfifo_alloc(__kfifo, size, sizeof(*__tmp->type), gfp_mask) : \
    -EINVAL; \
}) \
)

#define kfifo_free(fifo) \
({ \
    typeof((fifo) + 1) __tmp = (fifo); \
    struct __kfifo *__kfifo = &__tmp->kfifo; \
    if (__is_kfifo_ptr(__tmp)) \
        __kfifo_free(__kfifo); \
})

#define kfifo_init(fifo, buffer, size) \
({ \
    typeof((fifo) + 1) __tmp = (fifo); \
    struct __kfifo *__kfifo = &__tmp->kfifo; \
    __is_kfifo_ptr(__tmp) ? \
    __kfifo_init(__kfifo, buffer, size, sizeof(*__tmp->type)) : \
    -EINVAL; \
})

#define kfifo_put(fifo, val) \
({ \
    typeof((fifo) + 1) __tmp = (fifo); \
    typeof((val) + 1) __val = (val); \
    unsigned int __ret; \
    const size_t __recsize = sizeof(*__tmp->rectype); \
    struct __kfifo *__kfifo = &__tmp->kfifo; \
    if (0) { \
        typeof(__tmp->ptr_const) __dummy __attribute__ ((unused)); \
        __dummy = (typeof(__val))NULL; \
    } \
    if (__recsize) \
        __ret = __kfifo_in_r(__kfifo, __val, sizeof(*__val), \
            __recsize); \
    else { \
        __ret = !kfifo_is_full(__tmp); \
        if (__ret) { \
            (__is_kfifo_ptr(__tmp) ? \
            ((typeof(__tmp->type))__kfifo->data) : \
            (__tmp->buf) \
            )[__kfifo->in & __tmp->kfifo.mask] = \
                *(typeof(__tmp->type))__val; \
            smp_wmb(); \
            __kfifo->in++; \
        } \
    } \
    __ret; \
})

#define kfifo_get(fifo, val) \
__kfifo_uint_must_check_helper( \
({ \
    typeof((fifo) + 1) __tmp = (fifo); \
    typeof((val) + 1) __val = (val); \
    unsigned int __ret; \
    const size_t __recsize = sizeof(*__tmp->rectype); \
    struct __kfifo *__kfifo = &__tmp->kfifo; \
    if (0) \
        __val = (typeof(__tmp->ptr))0; \
    if (__recsize) \
        __ret = __kfifo_out_r(__kfifo, __val, sizeof(*__val), \
            __recsize); \
    else { \
        __ret = !kfifo_is_empty(__tmp); \
        if (__ret) { \
            *(typeof(__tmp->type))__val = \
                (__is_kfifo_ptr(__tmp) ? \
                ((typeof(__tmp->type))__kfifo->data) : \
                (__tmp->buf) \
                )[__kfifo->out & __tmp->kfifo.mask]; \
            smp_wmb(); \
            __kfifo->out++; \
        } \
    } \
    __ret; \
}) \
)

#define kfifo_peek(fifo, val) \
__kfifo_uint_must_check_helper( \
({ \
    typeof((fifo) + 1) __tmp = (fifo); \
    typeof((val) + 1) __val = (val); \
    unsigned int __ret; \
    const size_t __recsize = sizeof(*__tmp->rectype); \
    struct __kfifo *__kfifo = &__tmp->kfifo; \
    if (0) \
        __val = (typeof(__tmp->ptr))NULL; \
    if (__recsize) \
        __ret = __kfifo_out_peek_r(__kfifo, __val, sizeof(*__val), \
            __recsize); \
    else { \
        __ret = !kfifo_is_empty(__tmp); \
        if (__ret) { \
            *(typeof(__tmp->type))__val = \
                (__is_kfifo_ptr(__tmp) ? \
                ((typeof(__tmp->type))__kfifo->data) : \
                (__tmp->buf) \
                )[__kfifo->out & __tmp->kfifo.mask]; \
            smp_wmb(); \
        } \
    } \
    __ret; \
}) \
)

#define kfifo_in(fifo, buf, n) \
({ \
    typeof((fifo) + 1) __tmp = (fifo); \
    typeof((buf) + 1) __buf = (buf); \
    unsigned long __n = (n); \
    const size_t __recsize = sizeof(*__tmp->rectype); \
    struct __kfifo *__kfifo = &__tmp->kfifo; \
    if (0) { \
        typeof(__tmp->ptr_const) __dummy __attribute__ ((unused)); \
        __dummy = (typeof(__buf))NULL; \
    } \
    (__recsize) ?\
    __kfifo_in_r(__kfifo, __buf, __n, __recsize) : \
    __kfifo_in(__kfifo, __buf, __n); \
})

#define kfifo_in_spinlocked(fifo, buf, n, lock) \
({ \
    unsigned long __flags; \
    unsigned int __ret; \
    spin_lock_irqsave(lock, __flags); \
    __ret = kfifo_in(fifo, buf, n); \
    spin_unlock_irqrestore(lock, __flags); \
    __ret; \
})

/* alias for kfifo_in_spinlocked, will be removed in a future release */
#define kfifo_in_locked(fifo, buf, n, lock) \
        kfifo_in_spinlocked(fifo, buf, n, lock)

#define kfifo_out(fifo, buf, n) \
__kfifo_uint_must_check_helper( \
({ \
    typeof((fifo) + 1) __tmp = (fifo); \
    typeof((buf) + 1) __buf = (buf); \
    unsigned long __n = (n); \
    const size_t __recsize = sizeof(*__tmp->rectype); \
    struct __kfifo *__kfifo = &__tmp->kfifo; \
    if (0) { \
        typeof(__tmp->ptr) __dummy = NULL; \
        __buf = __dummy; \
    } \
    (__recsize) ?\
    __kfifo_out_r(__kfifo, __buf, __n, __recsize) : \
    __kfifo_out(__kfifo, __buf, __n); \
}) \
)

#define kfifo_out_spinlocked(fifo, buf, n, lock) \
__kfifo_uint_must_check_helper( \
({ \
    unsigned long __flags; \
    unsigned int __ret; \
    spin_lock_irqsave(lock, __flags); \
    __ret = kfifo_out(fifo, buf, n); \
    spin_unlock_irqrestore(lock, __flags); \
    __ret; \
}) \
)

/* alias for kfifo_out_spinlocked, will be removed in a future release */
#define kfifo_out_locked(fifo, buf, n, lock) \
        kfifo_out_spinlocked(fifo, buf, n, lock)

#define kfifo_from_user(fifo, from, len, copied) \
__kfifo_uint_must_check_helper( \
({ \
    typeof((fifo) + 1) __tmp = (fifo); \
    const void __user *__from = (from); \
    unsigned int __len = (len); \
    unsigned int *__copied = (copied); \
    const size_t __recsize = sizeof(*__tmp->rectype); \
    struct __kfifo *__kfifo = &__tmp->kfifo; \
    (__recsize) ? \
    __kfifo_from_user_r(__kfifo, __from, __len,  __copied, __recsize) : \
    __kfifo_from_user(__kfifo, __from, __len, __copied); \
}) \
)

#define kfifo_to_user(fifo, to, len, copied) \
__kfifo_uint_must_check_helper( \
({ \
    typeof((fifo) + 1) __tmp = (fifo); \
    void __user *__to = (to); \
    unsigned int __len = (len); \
    unsigned int *__copied = (copied); \
    const size_t __recsize = sizeof(*__tmp->rectype); \
    struct __kfifo *__kfifo = &__tmp->kfifo; \
    (__recsize) ? \
    __kfifo_to_user_r(__kfifo, __to, __len, __copied, __recsize) : \
    __kfifo_to_user(__kfifo, __to, __len, __copied); \
}) \
)

#define kfifo_dma_in_prepare(fifo, sgl, nents, len) \
({ \
    typeof((fifo) + 1) __tmp = (fifo); \
    struct scatterlist *__sgl = (sgl); \
    int __nents = (nents); \
    unsigned int __len = (len); \
    const size_t __recsize = sizeof(*__tmp->rectype); \
    struct __kfifo *__kfifo = &__tmp->kfifo; \
    (__recsize) ? \
    __kfifo_dma_in_prepare_r(__kfifo, __sgl, __nents, __len, __recsize) : \
    __kfifo_dma_in_prepare(__kfifo, __sgl, __nents, __len); \
})

#define kfifo_dma_in_finish(fifo, len) \
(void)({ \
    typeof((fifo) + 1) __tmp = (fifo); \
    unsigned int __len = (len); \
    const size_t __recsize = sizeof(*__tmp->rectype); \
    struct __kfifo *__kfifo = &__tmp->kfifo; \
    if (__recsize) \
        __kfifo_dma_in_finish_r(__kfifo, __len, __recsize); \
    else \
        __kfifo->in += __len / sizeof(*__tmp->type); \
})

#define kfifo_dma_out_prepare(fifo, sgl, nents, len) \
({ \
    typeof((fifo) + 1) __tmp = (fifo);  \
    struct scatterlist *__sgl = (sgl); \
    int __nents = (nents); \
    unsigned int __len = (len); \
    const size_t __recsize = sizeof(*__tmp->rectype); \
    struct __kfifo *__kfifo = &__tmp->kfifo; \
    (__recsize) ? \
    __kfifo_dma_out_prepare_r(__kfifo, __sgl, __nents, __len, __recsize) : \
    __kfifo_dma_out_prepare(__kfifo, __sgl, __nents, __len); \
})

#define kfifo_dma_out_finish(fifo, len) \
(void)({ \
    typeof((fifo) + 1) __tmp = (fifo); \
    unsigned int __len = (len); \
    const size_t __recsize = sizeof(*__tmp->rectype); \
    struct __kfifo *__kfifo = &__tmp->kfifo; \
    if (__recsize) \
        __kfifo_dma_out_finish_r(__kfifo, __recsize); \
    else \
        __kfifo->out += __len / sizeof(*__tmp->type); \
})

#define kfifo_out_peek(fifo, buf, n) \
__kfifo_uint_must_check_helper( \
({ \
    typeof((fifo) + 1) __tmp = (fifo); \
    typeof((buf) + 1) __buf = (buf); \
    unsigned long __n = (n); \
    const size_t __recsize = sizeof(*__tmp->rectype); \
    struct __kfifo *__kfifo = &__tmp->kfifo; \
    if (0) { \
        typeof(__tmp->ptr) __dummy __attribute__ ((unused)) = NULL; \
        __buf = __dummy; \
    } \
    (__recsize) ? \
    __kfifo_out_peek_r(__kfifo, __buf, __n, __recsize) : \
    __kfifo_out_peek(__kfifo, __buf, __n); \
}) \
)

extern int __kfifo_alloc(struct __kfifo *fifo, unsigned int size,
    size_t esize, gfp_t gfp_mask);

extern void __kfifo_free(struct __kfifo *fifo);

extern int __kfifo_init(struct __kfifo *fifo, void *buffer,
    unsigned int size, size_t esize);

extern unsigned int __kfifo_in(struct __kfifo *fifo,
    const void *buf, unsigned int len);

extern unsigned int __kfifo_out(struct __kfifo *fifo,
    void *buf, unsigned int len);

extern int __kfifo_from_user(struct __kfifo *fifo,
    const void __user *from, unsigned long len, unsigned int *copied);

extern int __kfifo_to_user(struct __kfifo *fifo,
    void __user *to, unsigned long len, unsigned int *copied);

extern unsigned int __kfifo_dma_in_prepare(struct __kfifo *fifo,
    struct scatterlist *sgl, int nents, unsigned int len);

extern unsigned int __kfifo_dma_out_prepare(struct __kfifo *fifo,
    struct scatterlist *sgl, int nents, unsigned int len);

extern unsigned int __kfifo_out_peek(struct __kfifo *fifo,
    void *buf, unsigned int len);

extern unsigned int __kfifo_in_r(struct __kfifo *fifo,
    const void *buf, unsigned int len, size_t recsize);

extern unsigned int __kfifo_out_r(struct __kfifo *fifo,
    void *buf, unsigned int len, size_t recsize);

extern int __kfifo_from_user_r(struct __kfifo *fifo,
    const void __user *from, unsigned long len, unsigned int *copied,
    size_t recsize);

extern int __kfifo_to_user_r(struct __kfifo *fifo, void __user *to,
    unsigned long len, unsigned int *copied, size_t recsize);

extern unsigned int __kfifo_dma_in_prepare_r(struct __kfifo *fifo,
    struct scatterlist *sgl, int nents, unsigned int len, size_t recsize);

extern void __kfifo_dma_in_finish_r(struct __kfifo *fifo,
    unsigned int len, size_t recsize);

extern unsigned int __kfifo_dma_out_prepare_r(struct __kfifo *fifo,
    struct scatterlist *sgl, int nents, unsigned int len, size_t recsize);

extern void __kfifo_dma_out_finish_r(struct __kfifo *fifo, size_t recsize);

extern unsigned int __kfifo_len_r(struct __kfifo *fifo, size_t recsize);

extern void __kfifo_skip_r(struct __kfifo *fifo, size_t recsize);

extern unsigned int __kfifo_out_peek_r(struct __kfifo *fifo,
    void *buf, unsigned int len, size_t recsize);

extern unsigned int __kfifo_max_r(unsigned int len, size_t recsize);

#endif