diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/kfifo.h | 330 |
1 files changed, 330 insertions, 0 deletions
diff --git a/include/linux/kfifo.h b/include/linux/kfifo.h index d3230fb08bc7..486e8ad3bb50 100644 --- a/include/linux/kfifo.h +++ b/include/linux/kfifo.h @@ -278,4 +278,334 @@ static inline unsigned int __kfifo_off(struct kfifo *fifo, unsigned int off) return off & (fifo->size - 1); } +/** + * __kfifo_peek_n internal helper function for determinate the length of + * the next record in the fifo + */ +static inline unsigned int __kfifo_peek_n(struct kfifo *fifo, + unsigned int recsize) +{ +#define __KFIFO_GET(fifo, off, shift) \ + ((fifo)->buffer[__kfifo_off((fifo), (fifo)->out+(off))] << (shift)) + + unsigned int l; + + l = __KFIFO_GET(fifo, 0, 0); + + if (--recsize) + l |= __KFIFO_GET(fifo, 1, 8); + + return l; +#undef __KFIFO_GET +} + +/** + * __kfifo_poke_n internal helper function for storing the length of + * the next record into the fifo + */ +static inline void __kfifo_poke_n(struct kfifo *fifo, + unsigned int recsize, unsigned int n) +{ +#define __KFIFO_PUT(fifo, off, val, shift) \ + ( \ + (fifo)->buffer[__kfifo_off((fifo), (fifo)->in+(off))] = \ + (unsigned char)((val) >> (shift)) \ + ) + + __KFIFO_PUT(fifo, 0, n, 0); + + if (--recsize) + __KFIFO_PUT(fifo, 1, n, 8); +#undef __KFIFO_PUT +} + +/** + * __kfifo_in_... internal functions for put date into the fifo + * do not call it directly, use kfifo_in_rec() instead + */ +extern unsigned int __kfifo_in_n(struct kfifo *fifo, + const void *from, unsigned int n, unsigned int recsize); + +extern unsigned int __kfifo_in_generic(struct kfifo *fifo, + const void *from, unsigned int n, unsigned int recsize); + +static inline unsigned int __kfifo_in_rec(struct kfifo *fifo, + const void *from, unsigned int n, unsigned int recsize) +{ + unsigned int ret; + + ret = __kfifo_in_n(fifo, from, n, recsize); + + if (likely(ret == 0)) { + if (recsize) + __kfifo_poke_n(fifo, recsize, n); + __kfifo_add_in(fifo, n + recsize); + } + return ret; +} + +/** + * kfifo_in_rec - puts some record data into the FIFO + * @fifo: the fifo to be used. + * @from: the data to be added. + * @n: the length of the data to be added. + * @recsize: size of record field + * + * This function copies @n bytes from the @from into the FIFO and returns + * the number of bytes which cannot be copied. + * A returned value greater than the @n value means that the record doesn't + * fit into the buffer. + * + * Note that with only one concurrent reader and one concurrent + * writer, you don't need extra locking to use these functions. + */ +static inline __must_check unsigned int kfifo_in_rec(struct kfifo *fifo, + void *from, unsigned int n, unsigned int recsize) +{ + if (!__builtin_constant_p(recsize)) + return __kfifo_in_generic(fifo, from, n, recsize); + return __kfifo_in_rec(fifo, from, n, recsize); +} + +/** + * __kfifo_out_... internal functions for get date from the fifo + * do not call it directly, use kfifo_out_rec() instead + */ +extern unsigned int __kfifo_out_n(struct kfifo *fifo, + void *to, unsigned int reclen, unsigned int recsize); + +extern unsigned int __kfifo_out_generic(struct kfifo *fifo, + void *to, unsigned int n, + unsigned int recsize, unsigned int *total); + +static inline unsigned int __kfifo_out_rec(struct kfifo *fifo, + void *to, unsigned int n, unsigned int recsize, + unsigned int *total) +{ + unsigned int l; + + if (!recsize) { + l = n; + if (total) + *total = l; + } else { + l = __kfifo_peek_n(fifo, recsize); + if (total) + *total = l; + if (n < l) + return l; + } + + return __kfifo_out_n(fifo, to, l, recsize); +} + +/** + * kfifo_out_rec - gets some record data from the FIFO + * @fifo: the fifo to be used. + * @to: where the data must be copied. + * @n: the size of the destination buffer. + * @recsize: size of record field + * @total: pointer where the total number of to copied bytes should stored + * + * This function copies at most @n bytes from the FIFO to @to and returns the + * number of bytes which cannot be copied. + * A returned value greater than the @n value means that the record doesn't + * fit into the @to buffer. + * + * Note that with only one concurrent reader and one concurrent + * writer, you don't need extra locking to use these functions. + */ +static inline __must_check unsigned int kfifo_out_rec(struct kfifo *fifo, + void *to, unsigned int n, unsigned int recsize, + unsigned int *total) + +{ + if (!__builtin_constant_p(recsize)) + return __kfifo_out_generic(fifo, to, n, recsize, total); + return __kfifo_out_rec(fifo, to, n, recsize, total); +} + +/** + * __kfifo_from_user_... internal functions for transfer from user space into + * the fifo. do not call it directly, use kfifo_from_user_rec() instead + */ +extern unsigned int __kfifo_from_user_n(struct kfifo *fifo, + const void __user *from, unsigned int n, unsigned int recsize); + +extern unsigned int __kfifo_from_user_generic(struct kfifo *fifo, + const void __user *from, unsigned int n, unsigned int recsize); + +static inline unsigned int __kfifo_from_user_rec(struct kfifo *fifo, + const void __user *from, unsigned int n, unsigned int recsize) +{ + unsigned int ret; + + ret = __kfifo_from_user_n(fifo, from, n, recsize); + + if (likely(ret == 0)) { + if (recsize) + __kfifo_poke_n(fifo, recsize, n); + __kfifo_add_in(fifo, n + recsize); + } + return ret; +} + +/** + * kfifo_from_user_rec - puts some data from user space into the FIFO + * @fifo: the fifo to be used. + * @from: pointer to the data to be added. + * @n: the length of the data to be added. + * @recsize: size of record field + * + * This function copies @n bytes from the @from into the + * FIFO and returns the number of bytes which cannot be copied. + * + * If the returned value is equal or less the @n value, the copy_from_user() + * functions has failed. Otherwise the record doesn't fit into the buffer. + * + * Note that with only one concurrent reader and one concurrent + * writer, you don't need extra locking to use these functions. + */ +static inline __must_check unsigned int kfifo_from_user_rec(struct kfifo *fifo, + const void __user *from, unsigned int n, unsigned int recsize) +{ + if (!__builtin_constant_p(recsize)) + return __kfifo_from_user_generic(fifo, from, n, recsize); + return __kfifo_from_user_rec(fifo, from, n, recsize); +} + +/** + * __kfifo_to_user_... internal functions for transfer fifo data into user space + * do not call it directly, use kfifo_to_user_rec() instead + */ +extern unsigned int __kfifo_to_user_n(struct kfifo *fifo, + void __user *to, unsigned int n, unsigned int reclen, + unsigned int recsize); + +extern unsigned int __kfifo_to_user_generic(struct kfifo *fifo, + void __user *to, unsigned int n, unsigned int recsize, + unsigned int *total); + +static inline unsigned int __kfifo_to_user_rec(struct kfifo *fifo, + void __user *to, unsigned int n, + unsigned int recsize, unsigned int *total) +{ + unsigned int l; + + if (!recsize) { + l = n; + if (total) + *total = l; + } else { + l = __kfifo_peek_n(fifo, recsize); + if (total) + *total = l; + if (n < l) + return l; + } + + return __kfifo_to_user_n(fifo, to, n, l, recsize); +} + +/** + * kfifo_to_user_rec - gets data from the FIFO and write it to user space + * @fifo: the fifo to be used. + * @to: where the data must be copied. + * @n: the size of the destination buffer. + * @recsize: size of record field + * @total: pointer where the total number of to copied bytes should stored + * + * This function copies at most @n bytes from the FIFO to the @to. + * In case of an error, the function returns the number of bytes which cannot + * be copied. + * If the returned value is equal or less the @n value, the copy_to_user() + * functions has failed. Otherwise the record doesn't fit into the @to buffer. + * + * Note that with only one concurrent reader and one concurrent + * writer, you don't need extra locking to use these functions. + */ +static inline __must_check unsigned int kfifo_to_user_rec(struct kfifo *fifo, + void __user *to, unsigned int n, unsigned int recsize, + unsigned int *total) +{ + if (!__builtin_constant_p(recsize)) + return __kfifo_to_user_generic(fifo, to, n, recsize, total); + return __kfifo_to_user_rec(fifo, to, n, recsize, total); +} + +/** + * __kfifo_peek_... internal functions for peek into the next fifo record + * do not call it directly, use kfifo_peek_rec() instead + */ +extern unsigned int __kfifo_peek_generic(struct kfifo *fifo, + unsigned int recsize); + +/** + * kfifo_peek_rec - gets the size of the next FIFO record data + * @fifo: the fifo to be used. + * @recsize: size of record field + * + * This function returns the size of the next FIFO record in number of bytes + */ +static inline __must_check unsigned int kfifo_peek_rec(struct kfifo *fifo, + unsigned int recsize) +{ + if (!__builtin_constant_p(recsize)) + return __kfifo_peek_generic(fifo, recsize); + if (!recsize) + return kfifo_len(fifo); + return __kfifo_peek_n(fifo, recsize); +} + +/** + * __kfifo_skip_... internal functions for skip the next fifo record + * do not call it directly, use kfifo_skip_rec() instead + */ +extern void __kfifo_skip_generic(struct kfifo *fifo, unsigned int recsize); + +static inline void __kfifo_skip_rec(struct kfifo *fifo, + unsigned int recsize) +{ + unsigned int l; + + if (recsize) { + l = __kfifo_peek_n(fifo, recsize); + + if (l + recsize <= kfifo_len(fifo)) { + __kfifo_add_out(fifo, l + recsize); + return; + } + } + kfifo_reset_out(fifo); +} + +/** + * kfifo_skip_rec - skip the next fifo out record + * @fifo: the fifo to be used. + * @recsize: size of record field + * + * This function skips the next FIFO record + */ +static inline void kfifo_skip_rec(struct kfifo *fifo, + unsigned int recsize) +{ + if (!__builtin_constant_p(recsize)) + __kfifo_skip_generic(fifo, recsize); + else + __kfifo_skip_rec(fifo, recsize); +} + +/** + * kfifo_avail_rec - returns the number of bytes available in a record FIFO + * @fifo: the fifo to be used. + * @recsize: size of record field + */ +static inline __must_check unsigned int kfifo_avail_rec(struct kfifo *fifo, + unsigned int recsize) +{ + unsigned int l = kfifo_size(fifo) - kfifo_len(fifo); + + return (l > recsize) ? l - recsize : 0; +} + #endif |