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Diffstat (limited to 'kernel/include/linux/kfifo.h')
| -rw-r--r-- | kernel/include/linux/kfifo.h | 833 |
1 files changed, 833 insertions, 0 deletions
diff --git a/kernel/include/linux/kfifo.h b/kernel/include/linux/kfifo.h new file mode 100644 index 000000000..473b43678 --- /dev/null +++ b/kernel/include/linux/kfifo.h @@ -0,0 +1,833 @@ +/* + * A generic kernel FIFO implementation + * + * Copyright (C) 2013 Stefani Seibold <stefani@seibold.net> + * + * 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; \ + const datatype *const_type; \ + char (*rectype)[recsize]; \ + ptrtype *ptr; \ + ptrtype const *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)) + +/** + * DECLARE_KFIFO_PTR - macro to declare a fifo pointer object + * @fifo: name of the declared fifo + * @type: type of the fifo elements + */ +#define DECLARE_KFIFO_PTR(fifo, type) STRUCT_KFIFO_PTR(type) fifo + +/** + * DECLARE_KFIFO - macro to declare a fifo object + * @fifo: name of the declared fifo + * @type: type of the fifo elements + * @size: the number of elements in the fifo, this must be a power of 2 + */ +#define DECLARE_KFIFO(fifo, type, size) STRUCT_KFIFO(type, size) fifo + +/** + * INIT_KFIFO - Initialize a fifo declared by DECLARE_KFIFO + * @fifo: name of the declared fifo datatype + */ +#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_KFIFO - macro to define and initialize a fifo + * @fifo: name of the declared fifo datatype + * @type: type of the fifo elements + * @size: the number of elements in the fifo, this must be a power of 2 + * + * Note: the macro can be used for global and local fifo data type variables. + */ +#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; +} + +/** + * kfifo_initialized - Check if the fifo is initialized + * @fifo: address of the fifo to check + * + * Return %true if fifo is initialized, otherwise %false. + * Assumes the fifo was 0 before. + */ +#define kfifo_initialized(fifo) ((fifo)->kfifo.mask) + +/** + * kfifo_esize - returns the size of the element managed by the fifo + * @fifo: address of the fifo to be used + */ +#define kfifo_esize(fifo) ((fifo)->kfifo.esize) + +/** + * kfifo_recsize - returns the size of the record length field + * @fifo: address of the fifo to be used + */ +#define kfifo_recsize(fifo) (sizeof(*(fifo)->rectype)) + +/** + * kfifo_size - returns the size of the fifo in elements + * @fifo: address of the fifo to be used + */ +#define kfifo_size(fifo) ((fifo)->kfifo.mask + 1) + +/** + * kfifo_reset - removes the entire fifo content + * @fifo: address of the fifo to be used + * + * Note: usage of kfifo_reset() is dangerous. It should be only called when the + * fifo is exclusived locked or when it is secured that no other thread is + * accessing the fifo. + */ +#define kfifo_reset(fifo) \ +(void)({ \ + typeof((fifo) + 1) __tmp = (fifo); \ + __tmp->kfifo.in = __tmp->kfifo.out = 0; \ +}) + +/** + * kfifo_reset_out - skip fifo content + * @fifo: address of the fifo to be used + * + * Note: The usage of kfifo_reset_out() is safe until it will be only called + * from the reader thread and there is only one concurrent reader. Otherwise + * it is dangerous and must be handled in the same way as kfifo_reset(). + */ +#define kfifo_reset_out(fifo) \ +(void)({ \ + typeof((fifo) + 1) __tmp = (fifo); \ + __tmp->kfifo.out = __tmp->kfifo.in; \ +}) + +/** + * kfifo_len - returns the number of used elements in the fifo + * @fifo: address of the fifo to be used + */ +#define kfifo_len(fifo) \ +({ \ + typeof((fifo) + 1) __tmpl = (fifo); \ + __tmpl->kfifo.in - __tmpl->kfifo.out; \ +}) + +/** + * kfifo_is_empty - returns true if the fifo is empty + * @fifo: address of the fifo to be used + */ +#define kfifo_is_empty(fifo) \ +({ \ + typeof((fifo) + 1) __tmpq = (fifo); \ + __tmpq->kfifo.in == __tmpq->kfifo.out; \ +}) + +/** + * kfifo_is_full - returns true if the fifo is full + * @fifo: address of the fifo to be used + */ +#define kfifo_is_full(fifo) \ +({ \ + typeof((fifo) + 1) __tmpq = (fifo); \ + kfifo_len(__tmpq) > __tmpq->kfifo.mask; \ +}) + +/** + * kfifo_avail - returns the number of unused elements in the fifo + * @fifo: address of the fifo to be used + */ +#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; \ +}) \ +) + +/** + * kfifo_skip - skip output data + * @fifo: address of the fifo to be used + */ +#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++; \ +}) + +/** + * kfifo_peek_len - gets the size of the next fifo record + * @fifo: address of the fifo to be used + * + * This function returns the size of the next fifo record in number of bytes. + */ +#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); \ +}) \ +) + +/** + * kfifo_alloc - dynamically allocates a new fifo buffer + * @fifo: pointer to the fifo + * @size: the number of elements in the fifo, this must be a power of 2 + * @gfp_mask: get_free_pages mask, passed to kmalloc() + * + * This macro dynamically allocates a new fifo buffer. + * + * The numer of elements will be rounded-up to a power of 2. + * The fifo will be release with kfifo_free(). + * Return 0 if no error, otherwise an error code. + */ +#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; \ +}) \ +) + +/** + * kfifo_free - frees the fifo + * @fifo: the fifo to be freed + */ +#define kfifo_free(fifo) \ +({ \ + typeof((fifo) + 1) __tmp = (fifo); \ + struct __kfifo *__kfifo = &__tmp->kfifo; \ + if (__is_kfifo_ptr(__tmp)) \ + __kfifo_free(__kfifo); \ +}) + +/** + * kfifo_init - initialize a fifo using a preallocated buffer + * @fifo: the fifo to assign the buffer + * @buffer: the preallocated buffer to be used + * @size: the size of the internal buffer, this have to be a power of 2 + * + * This macro initialize a fifo using a preallocated buffer. + * + * The numer of elements will be rounded-up to a power of 2. + * Return 0 if no error, otherwise an error code. + */ +#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; \ +}) + +/** + * kfifo_put - put data into the fifo + * @fifo: address of the fifo to be used + * @val: the data to be added + * + * This macro copies the given value into the fifo. + * It returns 0 if the fifo was full. Otherwise it returns the number + * processed elements. + * + * Note that with only one concurrent reader and one concurrent + * writer, you don't need extra locking to use these macro. + */ +#define kfifo_put(fifo, val) \ +({ \ + typeof((fifo) + 1) __tmp = (fifo); \ + typeof(*__tmp->const_type) __val = (val); \ + unsigned int __ret; \ + size_t __recsize = sizeof(*__tmp->rectype); \ + struct __kfifo *__kfifo = &__tmp->kfifo; \ + 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; \ +}) + +/** + * kfifo_get - get data from the fifo + * @fifo: address of the fifo to be used + * @val: address where to store the data + * + * This macro reads the data from the fifo. + * It returns 0 if the fifo was empty. Otherwise it returns the number + * processed elements. + * + * Note that with only one concurrent reader and one concurrent + * writer, you don't need extra locking to use these macro. + */ +#define kfifo_get(fifo, val) \ +__kfifo_uint_must_check_helper( \ +({ \ + typeof((fifo) + 1) __tmp = (fifo); \ + typeof(__tmp->ptr) __val = (val); \ + unsigned int __ret; \ + const size_t __recsize = sizeof(*__tmp->rectype); \ + struct __kfifo *__kfifo = &__tmp->kfifo; \ + 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; \ +}) \ +) + +/** + * kfifo_peek - get data from the fifo without removing + * @fifo: address of the fifo to be used + * @val: address where to store the data + * + * This reads the data from the fifo without removing it from the fifo. + * It returns 0 if the fifo was empty. Otherwise it returns the number + * processed elements. + * + * Note that with only one concurrent reader and one concurrent + * writer, you don't need extra locking to use these macro. + */ +#define kfifo_peek(fifo, val) \ +__kfifo_uint_must_check_helper( \ +({ \ + typeof((fifo) + 1) __tmp = (fifo); \ + typeof(__tmp->ptr) __val = (val); \ + unsigned int __ret; \ + const size_t __recsize = sizeof(*__tmp->rectype); \ + struct __kfifo *__kfifo = &__tmp->kfifo; \ + 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; \ +}) \ +) + +/** + * kfifo_in - put data into the fifo + * @fifo: address of the fifo to be used + * @buf: the data to be added + * @n: number of elements to be added + * + * This macro copies the given buffer into the fifo and returns the + * number of copied elements. + * + * Note that with only one concurrent reader and one concurrent + * writer, you don't need extra locking to use these macro. + */ +#define kfifo_in(fifo, buf, n) \ +({ \ + typeof((fifo) + 1) __tmp = (fifo); \ + typeof(__tmp->ptr_const) __buf = (buf); \ + unsigned long __n = (n); \ + const size_t __recsize = sizeof(*__tmp->rectype); \ + struct __kfifo *__kfifo = &__tmp->kfifo; \ + (__recsize) ?\ + __kfifo_in_r(__kfifo, __buf, __n, __recsize) : \ + __kfifo_in(__kfifo, __buf, __n); \ +}) + +/** + * kfifo_in_spinlocked - put data into the fifo using a spinlock for locking + * @fifo: address of the fifo to be used + * @buf: the data to be added + * @n: number of elements to be added + * @lock: pointer to the spinlock to use for locking + * + * This macro copies the given values buffer into the fifo and returns the + * number of copied elements. + */ +#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) + +/** + * kfifo_out - get data from the fifo + * @fifo: address of the fifo to be used + * @buf: pointer to the storage buffer + * @n: max. number of elements to get + * + * This macro get some data from the fifo and return the numbers of elements + * copied. + * + * Note that with only one concurrent reader and one concurrent + * writer, you don't need extra locking to use these macro. + */ +#define kfifo_out(fifo, buf, n) \ +__kfifo_uint_must_check_helper( \ +({ \ + typeof((fifo) + 1) __tmp = (fifo); \ + typeof(__tmp->ptr) __buf = (buf); \ + unsigned long __n = (n); \ + const size_t __recsize = sizeof(*__tmp->rectype); \ + struct __kfifo *__kfifo = &__tmp->kfifo; \ + (__recsize) ?\ + __kfifo_out_r(__kfifo, __buf, __n, __recsize) : \ + __kfifo_out(__kfifo, __buf, __n); \ +}) \ +) + +/** + * kfifo_out_spinlocked - get data from the fifo using a spinlock for locking + * @fifo: address of the fifo to be used + * @buf: pointer to the storage buffer + * @n: max. number of elements to get + * @lock: pointer to the spinlock to use for locking + * + * This macro get the data from the fifo and return the numbers of elements + * copied. + */ +#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) + +/** + * kfifo_from_user - puts some data from user space into the fifo + * @fifo: address of the fifo to be used + * @from: pointer to the data to be added + * @len: the length of the data to be added + * @copied: pointer to output variable to store the number of copied bytes + * + * This macro copies at most @len bytes from the @from into the + * fifo, depending of the available space and returns -EFAULT/0. + * + * Note that with only one concurrent reader and one concurrent + * writer, you don't need extra locking to use these macro. + */ +#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); \ +}) \ +) + +/** + * kfifo_to_user - copies data from the fifo into user space + * @fifo: address of the fifo to be used + * @to: where the data must be copied + * @len: the size of the destination buffer + * @copied: pointer to output variable to store the number of copied bytes + * + * This macro copies at most @len bytes from the fifo into the + * @to buffer and returns -EFAULT/0. + * + * Note that with only one concurrent reader and one concurrent + * writer, you don't need extra locking to use these macro. + */ +#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); \ +}) \ +) + +/** + * kfifo_dma_in_prepare - setup a scatterlist for DMA input + * @fifo: address of the fifo to be used + * @sgl: pointer to the scatterlist array + * @nents: number of entries in the scatterlist array + * @len: number of elements to transfer + * + * This macro fills a scatterlist for DMA input. + * It returns the number entries in the scatterlist array. + * + * Note that with only one concurrent reader and one concurrent + * writer, you don't need extra locking to use these macros. + */ +#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); \ +}) + +/** + * kfifo_dma_in_finish - finish a DMA IN operation + * @fifo: address of the fifo to be used + * @len: number of bytes to received + * + * This macro finish a DMA IN operation. The in counter will be updated by + * the len parameter. No error checking will be done. + * + * Note that with only one concurrent reader and one concurrent + * writer, you don't need extra locking to use these macros. + */ +#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); \ +}) + +/** + * kfifo_dma_out_prepare - setup a scatterlist for DMA output + * @fifo: address of the fifo to be used + * @sgl: pointer to the scatterlist array + * @nents: number of entries in the scatterlist array + * @len: number of elements to transfer + * + * This macro fills a scatterlist for DMA output which at most @len bytes + * to transfer. + * It returns the number entries in the scatterlist array. + * A zero means there is no space available and the scatterlist is not filled. + * + * Note that with only one concurrent reader and one concurrent + * writer, you don't need extra locking to use these macros. + */ +#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); \ +}) + +/** + * kfifo_dma_out_finish - finish a DMA OUT operation + * @fifo: address of the fifo to be used + * @len: number of bytes transferred + * + * This macro finish a DMA OUT operation. The out counter will be updated by + * the len parameter. No error checking will be done. + * + * Note that with only one concurrent reader and one concurrent + * writer, you don't need extra locking to use these macros. + */ +#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); \ +}) + +/** + * kfifo_out_peek - gets some data from the fifo + * @fifo: address of the fifo to be used + * @buf: pointer to the storage buffer + * @n: max. number of elements to get + * + * This macro get the data from the fifo and return the numbers of elements + * copied. The data is not removed from the fifo. + * + * Note that with only one concurrent reader and one concurrent + * writer, you don't need extra locking to use these macro. + */ +#define kfifo_out_peek(fifo, buf, n) \ +__kfifo_uint_must_check_helper( \ +({ \ + typeof((fifo) + 1) __tmp = (fifo); \ + typeof(__tmp->ptr) __buf = (buf); \ + unsigned long __n = (n); \ + const size_t __recsize = sizeof(*__tmp->rectype); \ + struct __kfifo *__kfifo = &__tmp->kfifo; \ + (__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 |