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authorStefani Seibold <stefani@seibold.net>2010-08-10 21:03:38 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2010-08-11 11:59:23 -0400
commit4201d9a8e86b51dd40aa8a0dabd093376c859985 (patch)
tree6c5351812aab1e027056139c95982642890797ec /kernel
parent4457d9845927b3c62b6e833be243d21d6ca7df47 (diff)
kfifo: add the new generic kfifo API
Add the new version of the kfifo API files kfifo.c and kfifo.h. Signed-off-by: Stefani Seibold <stefani@seibold.net> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/kfifo-new.c602
1 files changed, 602 insertions, 0 deletions
diff --git a/kernel/kfifo-new.c b/kernel/kfifo-new.c
new file mode 100644
index 000000000000..02192dd905cc
--- /dev/null
+++ b/kernel/kfifo-new.c
@@ -0,0 +1,602 @@
1/*
2 * A generic kernel FIFO implementation
3 *
4 * Copyright (C) 2009/2010 Stefani Seibold <stefani@seibold.net>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19 *
20 */
21
22#include <linux/kernel.h>
23#include <linux/module.h>
24#include <linux/slab.h>
25#include <linux/err.h>
26#include <linux/log2.h>
27#include <linux/uaccess.h>
28#include <linux/kfifo.h>
29
30/*
31 * internal helper to calculate the unused elements in a fifo
32 */
33static inline unsigned int kfifo_unused(struct __kfifo *fifo)
34{
35 return (fifo->mask + 1) - (fifo->in - fifo->out);
36}
37
38int __kfifo_alloc(struct __kfifo *fifo, unsigned int size,
39 size_t esize, gfp_t gfp_mask)
40{
41 /*
42 * round down to the next power of 2, since our 'let the indices
43 * wrap' technique works only in this case.
44 */
45 if (!is_power_of_2(size))
46 size = rounddown_pow_of_two(size);
47
48 fifo->in = 0;
49 fifo->out = 0;
50 fifo->esize = esize;
51
52 if (size < 2) {
53 fifo->data = NULL;
54 fifo->mask = 0;
55 return -EINVAL;
56 }
57
58 fifo->data = kmalloc(size * esize, gfp_mask);
59
60 if (!fifo->data) {
61 fifo->mask = 0;
62 return -ENOMEM;
63 }
64 fifo->mask = size - 1;
65
66 return 0;
67}
68EXPORT_SYMBOL(__kfifo_alloc);
69
70void __kfifo_free(struct __kfifo *fifo)
71{
72 kfree(fifo->data);
73 fifo->in = 0;
74 fifo->out = 0;
75 fifo->esize = 0;
76 fifo->data = NULL;
77 fifo->mask = 0;
78}
79EXPORT_SYMBOL(__kfifo_free);
80
81int __kfifo_init(struct __kfifo *fifo, void *buffer,
82 unsigned int size, size_t esize)
83{
84 size /= esize;
85
86 if (!is_power_of_2(size))
87 size = rounddown_pow_of_two(size);
88
89 fifo->in = 0;
90 fifo->out = 0;
91 fifo->esize = esize;
92 fifo->data = buffer;
93
94 if (size < 2) {
95 fifo->mask = 0;
96 return -EINVAL;
97 }
98 fifo->mask = size - 1;
99
100 return 0;
101}
102EXPORT_SYMBOL(__kfifo_init);
103
104static void kfifo_copy_in(struct __kfifo *fifo, const void *src,
105 unsigned int len, unsigned int off)
106{
107 unsigned int size = fifo->mask + 1;
108 unsigned int esize = fifo->esize;
109 unsigned int l;
110
111 off &= fifo->mask;
112 if (esize != 1) {
113 off *= esize;
114 size *= esize;
115 len *= esize;
116 }
117 l = min(len, size - off);
118
119 memcpy(fifo->data + off, src, l);
120 memcpy(fifo->data, src + l, len - l);
121 /*
122 * make sure that the data in the fifo is up to date before
123 * incrementing the fifo->in index counter
124 */
125 smp_wmb();
126}
127
128unsigned int __kfifo_in(struct __kfifo *fifo,
129 const void *buf, unsigned int len)
130{
131 unsigned int l;
132
133 l = kfifo_unused(fifo);
134 if (len > l)
135 len = l;
136
137 kfifo_copy_in(fifo, buf, len, fifo->in);
138 fifo->in += len;
139 return len;
140}
141EXPORT_SYMBOL(__kfifo_in);
142
143static void kfifo_copy_out(struct __kfifo *fifo, void *dst,
144 unsigned int len, unsigned int off)
145{
146 unsigned int size = fifo->mask + 1;
147 unsigned int esize = fifo->esize;
148 unsigned int l;
149
150 off &= fifo->mask;
151 if (esize != 1) {
152 off *= esize;
153 size *= esize;
154 len *= esize;
155 }
156 l = min(len, size - off);
157
158 memcpy(dst, fifo->data + off, l);
159 memcpy(dst + l, fifo->data, len - l);
160 /*
161 * make sure that the data is copied before
162 * incrementing the fifo->out index counter
163 */
164 smp_wmb();
165}
166
167unsigned int __kfifo_out_peek(struct __kfifo *fifo,
168 void *buf, unsigned int len)
169{
170 unsigned int l;
171
172 l = fifo->in - fifo->out;
173 if (len > l)
174 len = l;
175
176 kfifo_copy_out(fifo, buf, len, fifo->out);
177 return len;
178}
179EXPORT_SYMBOL(__kfifo_out_peek);
180
181unsigned int __kfifo_out(struct __kfifo *fifo,
182 void *buf, unsigned int len)
183{
184 len = __kfifo_out_peek(fifo, buf, len);
185 fifo->out += len;
186 return len;
187}
188EXPORT_SYMBOL(__kfifo_out);
189
190static unsigned long kfifo_copy_from_user(struct __kfifo *fifo,
191 const void __user *from, unsigned int len, unsigned int off,
192 unsigned int *copied)
193{
194 unsigned int size = fifo->mask + 1;
195 unsigned int esize = fifo->esize;
196 unsigned int l;
197 unsigned long ret;
198
199 off &= fifo->mask;
200 if (esize != 1) {
201 off *= esize;
202 size *= esize;
203 len *= esize;
204 }
205 l = min(len, size - off);
206
207 ret = copy_from_user(fifo->data + off, from, l);
208 if (unlikely(ret))