1 /*- 2 * Copyright (c) 2021 Beckhoff Automation GmbH & Co. KG 3 * Copyright (c) 2022 Bjoern A. Zeeb 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 * 26 */ 27 28 #ifndef _LINUXKPI_LINUX_KFIFO_H_ 29 #define _LINUXKPI_LINUX_KFIFO_H_ 30 31 #include <sys/types.h> 32 33 #include <linux/array_size.h> 34 #include <linux/slab.h> 35 #include <linux/gfp.h> 36 37 /* 38 * INIT_KFIFO() is used to initialize the structure declared with 39 * DECLARE_KFIFO(). It doesn't work with DECLARE_KFIFO_PTR(). 40 */ 41 #define INIT_KFIFO(_kf) \ 42 ({ \ 43 (_kf).total = nitems((_kf).head); \ 44 (_kf).count = 0; \ 45 (_kf).first = 0; \ 46 (_kf).last = 0; \ 47 }) 48 49 #define DECLARE_KFIFO(_name, _type, _size) \ 50 struct kfifo_ ## _name { \ 51 size_t total; \ 52 size_t count; \ 53 size_t first; \ 54 size_t last; \ 55 _type head[_size]; \ 56 } _name 57 58 #define DECLARE_KFIFO_PTR(_name, _type) \ 59 struct kfifo_ ## _name { \ 60 size_t total; \ 61 size_t count; \ 62 size_t first; \ 63 size_t last; \ 64 _type *head; \ 65 } _name 66 67 #define kfifo_len(_kf) \ 68 ({ \ 69 (_kf)->count; \ 70 }) 71 72 #define kfifo_is_empty(_kf) \ 73 ({ \ 74 ((_kf)->count == 0) ? true : false; \ 75 }) 76 77 #define kfifo_is_full(_kf) \ 78 ({ \ 79 ((_kf)->count == (_kf)->total) ? true : false; \ 80 }) 81 82 #define kfifo_put(_kf, _e) \ 83 ({ \ 84 bool _rc; \ 85 \ 86 /* Would overflow. */ \ 87 if (kfifo_is_full(_kf)) { \ 88 _rc = false; \ 89 } else { \ 90 (_kf)->head[(_kf)->last] = (_e); \ 91 (_kf)->count++; \ 92 (_kf)->last++; \ 93 if ((_kf)->last >= (_kf)->total) \ 94 (_kf)->last = 0; \ 95 _rc = true; \ 96 } \ 97 \ 98 _rc; \ 99 }) 100 101 #define kfifo_get(_kf, _e) \ 102 ({ \ 103 bool _rc; \ 104 \ 105 if (kfifo_is_empty(_kf)) { \ 106 _rc = false; \ 107 } else { \ 108 *(_e) = (_kf)->head[(_kf)->first]; \ 109 (_kf)->count--; \ 110 (_kf)->first++; \ 111 if ((_kf)->first >= (_kf)->total) \ 112 (_kf)->first = 0; \ 113 _rc = true; \ 114 } \ 115 \ 116 _rc; \ 117 }) 118 119 #define kfifo_alloc(_kf, _s, _gfp) \ 120 ({ \ 121 int _error; \ 122 \ 123 (_kf)->head = kmalloc(sizeof(__typeof(*(_kf)->head)) * (_s), _gfp); \ 124 if ((_kf)->head == NULL) \ 125 _error = ENOMEM; \ 126 else { \ 127 (_kf)->total = (_s); \ 128 _error = 0; \ 129 } \ 130 \ 131 _error; \ 132 }) 133 134 #define kfifo_free(_kf) \ 135 ({ \ 136 kfree((_kf)->head); \ 137 (_kf)->head = NULL; \ 138 (_kf)->total = (_kf)->count = (_kf)->first = (_kf)->last = 0; \ 139 }) 140 141 #endif /* _LINUXKPI_LINUX_KFIFO_H_*/ 142