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-rw-r--r--kernel/kfifo.c408
1 files changed, 327 insertions, 81 deletions
diff --git a/kernel/kfifo.c b/kernel/kfifo.c
index 3765ff3c1bbe..32c5c15d750d 100644
--- a/kernel/kfifo.c
+++ b/kernel/kfifo.c
@@ -1,6 +1,7 @@
1/* 1/*
2 * A simple kernel FIFO implementation. 2 * A generic kernel FIFO implementation.
3 * 3 *
4 * Copyright (C) 2009 Stefani Seibold <stefani@seibold.net>
4 * Copyright (C) 2004 Stelian Pop <stelian@popies.net> 5 * Copyright (C) 2004 Stelian Pop <stelian@popies.net>
5 * 6 *
6 * This program is free software; you can redistribute it and/or modify 7 * This program is free software; you can redistribute it and/or modify
@@ -25,50 +26,48 @@
25#include <linux/err.h> 26#include <linux/err.h>
26#include <linux/kfifo.h> 27#include <linux/kfifo.h>
27#include <linux/log2.h> 28#include <linux/log2.h>
29#include <linux/uaccess.h>
30
31static void _kfifo_init(struct kfifo *fifo, void *buffer,
32 unsigned int size)
33{
34 fifo->buffer = buffer;
35 fifo->size = size;
36
37 kfifo_reset(fifo);
38}
28 39
29/** 40/**
30 * kfifo_init - allocates a new FIFO using a preallocated buffer 41 * kfifo_init - initialize a FIFO using a preallocated buffer
42 * @fifo: the fifo to assign the buffer
31 * @buffer: the preallocated buffer to be used. 43 * @buffer: the preallocated buffer to be used.
32 * @size: the size of the internal buffer, this have to be a power of 2. 44 * @size: the size of the internal buffer, this has to be a power of 2.
33 * @gfp_mask: get_free_pages mask, passed to kmalloc()
34 * @lock: the lock to be used to protect the fifo buffer
35 * 45 *
36 * Do NOT pass the kfifo to kfifo_free() after use! Simply free the
37 * &struct kfifo with kfree().
38 */ 46 */
39struct kfifo *kfifo_init(unsigned char *buffer, unsigned int size, 47void kfifo_init(struct kfifo *fifo, void *buffer, unsigned int size)
40 gfp_t gfp_mask, spinlock_t *lock)
41{ 48{
42 struct kfifo *fifo;
43
44 /* size must be a power of 2 */ 49 /* size must be a power of 2 */
45 BUG_ON(!is_power_of_2(size)); 50 BUG_ON(!is_power_of_2(size));
46 51
47 fifo = kmalloc(sizeof(struct kfifo), gfp_mask); 52 _kfifo_init(fifo, buffer, size);
48 if (!fifo)
49 return ERR_PTR(-ENOMEM);
50
51 fifo->buffer = buffer;
52 fifo->size = size;
53 fifo->in = fifo->out = 0;
54 fifo->lock = lock;
55
56 return fifo;
57} 53}
58EXPORT_SYMBOL(kfifo_init); 54EXPORT_SYMBOL(kfifo_init);
59 55
60/** 56/**
61 * kfifo_alloc - allocates a new FIFO and its internal buffer 57 * kfifo_alloc - allocates a new FIFO internal buffer
62 * @size: the size of the internal buffer to be allocated. 58 * @fifo: the fifo to assign then new buffer
59 * @size: the size of the buffer to be allocated, this have to be a power of 2.
63 * @gfp_mask: get_free_pages mask, passed to kmalloc() 60 * @gfp_mask: get_free_pages mask, passed to kmalloc()
64 * @lock: the lock to be used to protect the fifo buffer 61 *
62 * This function dynamically allocates a new fifo internal buffer
65 * 63 *
66 * The size will be rounded-up to a power of 2. 64 * The size will be rounded-up to a power of 2.
65 * The buffer will be release with kfifo_free().
66 * Return 0 if no error, otherwise the an error code
67 */ 67 */
68struct kfifo *kfifo_alloc(unsigned int size, gfp_t gfp_mask, spinlock_t *lock) 68int kfifo_alloc(struct kfifo *fifo, unsigned int size, gfp_t gfp_mask)
69{ 69{
70 unsigned char *buffer; 70 unsigned char *buffer;
71 struct kfifo *ret;
72 71
73 /* 72 /*
74 * round up to the next power of 2, since our 'let the indices 73 * round up to the next power of 2, since our 'let the indices
@@ -80,48 +79,92 @@ struct kfifo *kfifo_alloc(unsigned int size, gfp_t gfp_mask, spinlock_t *lock)
80 } 79 }
81 80
82 buffer = kmalloc(size, gfp_mask); 81 buffer = kmalloc(size, gfp_mask);
83 if (!buffer) 82 if (!buffer) {
84 return ERR_PTR(-ENOMEM); 83 _kfifo_init(fifo, 0, 0);
85 84 return -ENOMEM;
86 ret = kfifo_init(buffer, size, gfp_mask, lock); 85 }
87 86
88 if (IS_ERR(ret)) 87 _kfifo_init(fifo, buffer, size);
89 kfree(buffer);
90 88
91 return ret; 89 return 0;
92} 90}
93EXPORT_SYMBOL(kfifo_alloc); 91EXPORT_SYMBOL(kfifo_alloc);
94 92
95/** 93/**
96 * kfifo_free - frees the FIFO 94 * kfifo_free - frees the FIFO internal buffer
97 * @fifo: the fifo to be freed. 95 * @fifo: the fifo to be freed.
98 */ 96 */
99void kfifo_free(struct kfifo *fifo) 97void kfifo_free(struct kfifo *fifo)
100{ 98{
101 kfree(fifo->buffer); 99 kfree(fifo->buffer);
102 kfree(fifo);
103} 100}
104EXPORT_SYMBOL(kfifo_free); 101EXPORT_SYMBOL(kfifo_free);
105 102
106/** 103/**
107 * __kfifo_put - puts some data into the FIFO, no locking version 104 * kfifo_skip - skip output data
108 * @fifo: the fifo to be used. 105 * @fifo: the fifo to be used.
109 * @buffer: the data to be added. 106 * @len: number of bytes to skip
110 * @len: the length of the data to be added.
111 *
112 * This function copies at most @len bytes from the @buffer into
113 * the FIFO depending on the free space, and returns the number of
114 * bytes copied.
115 *
116 * Note that with only one concurrent reader and one concurrent
117 * writer, you don't need extra locking to use these functions.
118 */ 107 */
119unsigned int __kfifo_put(struct kfifo *fifo, 108void kfifo_skip(struct kfifo *fifo, unsigned int len)
120 const unsigned char *buffer, unsigned int len) 109{
110 if (len < kfifo_len(fifo)) {
111 __kfifo_add_out(fifo, len);
112 return;
113 }
114 kfifo_reset_out(fifo);
115}
116EXPORT_SYMBOL(kfifo_skip);
117
118static inline void __kfifo_in_data(struct kfifo *fifo,
119 const void *from, unsigned int len, unsigned int off)
121{ 120{
122 unsigned int l; 121 unsigned int l;
123 122
124 len = min(len, fifo->size - fifo->in + fifo->out); 123 /*
124 * Ensure that we sample the fifo->out index -before- we
125 * start putting bytes into the kfifo.
126 */
127
128 smp_mb();
129
130 off = __kfifo_off(fifo, fifo->in + off);
131
132 /* first put the data starting from fifo->in to buffer end */
133 l = min(len, fifo->size - off);
134 memcpy(fifo->buffer + off, from, l);
135
136 /* then put the rest (if any) at the beginning of the buffer */
137 memcpy(fifo->buffer, from + l, len - l);
138}
139
140static inline void __kfifo_out_data(struct kfifo *fifo,
141 void *to, unsigned int len, unsigned int off)
142{
143 unsigned int l;
144
145 /*
146 * Ensure that we sample the fifo->in index -before- we
147 * start removing bytes from the kfifo.
148 */
149
150 smp_rmb();
151
152 off = __kfifo_off(fifo, fifo->out + off);
153
154 /* first get the data from fifo->out until the end of the buffer */
155 l = min(len, fifo->size - off);
156 memcpy(to, fifo->buffer + off, l);
157
158 /* then get the rest (if any) from the beginning of the buffer */
159 memcpy(to + l, fifo->buffer, len - l);
160}
161
162static inline int __kfifo_from_user_data(struct kfifo *fifo,
163 const void __user *from, unsigned int len, unsigned int off,
164 unsigned *lenout)
165{
166 unsigned int l;
167 int ret;
125 168
126 /* 169 /*
127 * Ensure that we sample the fifo->out index -before- we 170 * Ensure that we sample the fifo->out index -before- we
@@ -130,68 +173,271 @@ unsigned int __kfifo_put(struct kfifo *fifo,
130 173
131 smp_mb(); 174 smp_mb();
132 175
176 off = __kfifo_off(fifo, fifo->in + off);
177
133 /* first put the data starting from fifo->in to buffer end */ 178 /* first put the data starting from fifo->in to buffer end */
134 l = min(len, fifo->size - (fifo->in & (fifo->size - 1))); 179 l = min(len, fifo->size - off);
135 memcpy(fifo->buffer + (fifo->in & (fifo->size - 1)), buffer, l); 180 ret = copy_from_user(fifo->buffer + off, from, l);
181 if (unlikely(ret)) {
182 *lenout = ret;
183 return -EFAULT;
184 }
185 *lenout = l;
136 186
137 /* then put the rest (if any) at the beginning of the buffer */ 187 /* then put the rest (if any) at the beginning of the buffer */
138 memcpy(fifo->buffer, buffer + l, len - l); 188 ret = copy_from_user(fifo->buffer, from + l, len - l);
189 *lenout += ret ? ret : len - l;
190 return ret ? -EFAULT : 0;
191}
192
193static inline int __kfifo_to_user_data(struct kfifo *fifo,
194 void __user *to, unsigned int len, unsigned int off, unsigned *lenout)
195{
196 unsigned int l;
197 int ret;
139 198
140 /* 199 /*
141 * Ensure that we add the bytes to the kfifo -before- 200 * Ensure that we sample the fifo->in index -before- we
142 * we update the fifo->in index. 201 * start removing bytes from the kfifo.
143 */ 202 */
144 203
145 smp_wmb(); 204 smp_rmb();
205
206 off = __kfifo_off(fifo, fifo->out + off);
207
208 /* first get the data from fifo->out until the end of the buffer */
209 l = min(len, fifo->size - off);
210 ret = copy_to_user(to, fifo->buffer + off, l);
211 *lenout = l;
212 if (unlikely(ret)) {
213 *lenout -= ret;
214 return -EFAULT;
215 }
216
217 /* then get the rest (if any) from the beginning of the buffer */
218 len -= l;
219 ret = copy_to_user(to + l, fifo->buffer, len);
220 if (unlikely(ret)) {
221 *lenout += len - ret;
222 return -EFAULT;
223 }
224 *lenout += len;
225 return 0;
226}
227
228unsigned int __kfifo_in_n(struct kfifo *fifo,
229 const void *from, unsigned int len, unsigned int recsize)
230{
231 if (kfifo_avail(fifo) < len + recsize)
232 return len + 1;
233
234 __kfifo_in_data(fifo, from, len, recsize);
235 return 0;
236}
237EXPORT_SYMBOL(__kfifo_in_n);
146 238
147 fifo->in += len; 239/**
240 * kfifo_in - puts some data into the FIFO
241 * @fifo: the fifo to be used.
242 * @from: the data to be added.
243 * @len: the length of the data to be added.
244 *
245 * This function copies at most @len bytes from the @from buffer into
246 * the FIFO depending on the free space, and returns the number of
247 * bytes copied.
248 *
249 * Note that with only one concurrent reader and one concurrent
250 * writer, you don't need extra locking to use these functions.
251 */
252unsigned int kfifo_in(struct kfifo *fifo, const void *from,
253 unsigned int len)
254{
255 len = min(kfifo_avail(fifo), len);
148 256
257 __kfifo_in_data(fifo, from, len, 0);
258 __kfifo_add_in(fifo, len);
149 return len; 259 return len;
150} 260}
151EXPORT_SYMBOL(__kfifo_put); 261EXPORT_SYMBOL(kfifo_in);
262
263unsigned int __kfifo_in_generic(struct kfifo *fifo,
264 const void *from, unsigned int len, unsigned int recsize)
265{
266 return __kfifo_in_rec(fifo, from, len, recsize);
267}
268EXPORT_SYMBOL(__kfifo_in_generic);
269
270unsigned int __kfifo_out_n(struct kfifo *fifo,
271 void *to, unsigned int len, unsigned int recsize)
272{
273 if (kfifo_len(fifo) < len + recsize)
274 return len;
275
276 __kfifo_out_data(fifo, to, len, recsize);
277 __kfifo_add_out(fifo, len + recsize);
278 return 0;
279}
280EXPORT_SYMBOL(__kfifo_out_n);
152 281
153/** 282/**
154 * __kfifo_get - gets some data from the FIFO, no locking version 283 * kfifo_out - gets some data from the FIFO
155 * @fifo: the fifo to be used. 284 * @fifo: the fifo to be used.
156 * @buffer: where the data must be copied. 285 * @to: where the data must be copied.
157 * @len: the size of the destination buffer. 286 * @len: the size of the destination buffer.
158 * 287 *
159 * This function copies at most @len bytes from the FIFO into the 288 * This function copies at most @len bytes from the FIFO into the
160 * @buffer and returns the number of copied bytes. 289 * @to buffer and returns the number of copied bytes.
161 * 290 *
162 * Note that with only one concurrent reader and one concurrent 291 * Note that with only one concurrent reader and one concurrent
163 * writer, you don't need extra locking to use these functions. 292 * writer, you don't need extra locking to use these functions.
164 */ 293 */
165unsigned int __kfifo_get(struct kfifo *fifo, 294unsigned int kfifo_out(struct kfifo *fifo, void *to, unsigned int len)
166 unsigned char *buffer, unsigned int len)
167{ 295{
168 unsigned int l; 296 len = min(kfifo_len(fifo), len);
169 297
170 len = min(len, fifo->in - fifo->out); 298 __kfifo_out_data(fifo, to, len, 0);
299 __kfifo_add_out(fifo, len);
171 300
172 /* 301 return len;
173 * Ensure that we sample the fifo->in index -before- we 302}
174 * start removing bytes from the kfifo. 303EXPORT_SYMBOL(kfifo_out);
175 */
176 304
177 smp_rmb(); 305/**
306 * kfifo_out_peek - copy some data from the FIFO, but do not remove it
307 * @fifo: the fifo to be used.
308 * @to: where the data must be copied.
309 * @len: the size of the destination buffer.
310 * @offset: offset into the fifo
311 *
312 * This function copies at most @len bytes at @offset from the FIFO
313 * into the @to buffer and returns the number of copied bytes.
314 * The data is not removed from the FIFO.
315 */
316unsigned int kfifo_out_peek(struct kfifo *fifo, void *to, unsigned int len,
317 unsigned offset)
318{
319 len = min(kfifo_len(fifo), len + offset);
178 320
179 /* first get the data from fifo->out until the end of the buffer */ 321 __kfifo_out_data(fifo, to, len, offset);
180 l = min(len, fifo->size - (fifo->out & (fifo->size - 1))); 322 return len;
181 memcpy(buffer, fifo->buffer + (fifo->out & (fifo->size - 1)), l); 323}
324EXPORT_SYMBOL(kfifo_out_peek);
182 325
183 /* then get the rest (if any) from the beginning of the buffer */ 326unsigned int __kfifo_out_generic(struct kfifo *fifo,
184 memcpy(buffer + l, fifo->buffer, len - l); 327 void *to, unsigned int len, unsigned int recsize,
328 unsigned int *total)
329{
330 return __kfifo_out_rec(fifo, to, len, recsize, total);
331}
332EXPORT_SYMBOL(__kfifo_out_generic);
185 333
186 /* 334unsigned int __kfifo_from_user_n(struct kfifo *fifo,
187 * Ensure that we remove the bytes from the kfifo -before- 335 const void __user *from, unsigned int len, unsigned int recsize)
188 * we update the fifo->out index. 336{
189 */ 337 unsigned total;
190 338
191 smp_mb(); 339 if (kfifo_avail(fifo) < len + recsize)
340 return len + 1;
192 341
193 fifo->out += len; 342 __kfifo_from_user_data(fifo, from, len, recsize, &total);
343 return total;
344}
345EXPORT_SYMBOL(__kfifo_from_user_n);
194 346
195 return len; 347/**
348 * kfifo_from_user - puts some data from user space into the FIFO
349 * @fifo: the fifo to be used.
350 * @from: pointer to the data to be added.
351 * @len: the length of the data to be added.
352 *
353 * This function copies at most @len bytes from the @from into the
354 * FIFO depending and returns -EFAULT/0.
355 *
356 * Note that with only one concurrent reader and one concurrent
357 * writer, you don't need extra locking to use these functions.
358 */
359int kfifo_from_user(struct kfifo *fifo,
360 const void __user *from, unsigned int len, unsigned *total)
361{
362 int ret;
363 len = min(kfifo_avail(fifo), len);
364 ret = __kfifo_from_user_data(fifo, from, len, 0, total);
365 if (ret)
366 return ret;
367 __kfifo_add_in(fifo, len);
368 return 0;
196} 369}
197EXPORT_SYMBOL(__kfifo_get); 370EXPORT_SYMBOL(kfifo_from_user);
371
372unsigned int __kfifo_from_user_generic(struct kfifo *fifo,
373 const void __user *from, unsigned int len, unsigned int recsize)
374{
375 return __kfifo_from_user_rec(fifo, from, len, recsize);
376}
377EXPORT_SYMBOL(__kfifo_from_user_generic);
378
379unsigned int __kfifo_to_user_n(struct kfifo *fifo,
380 void __user *to, unsigned int len, unsigned int reclen,
381 unsigned int recsize)
382{
383 unsigned int ret, total;
384
385 if (kfifo_len(fifo) < reclen + recsize)
386 return len;
387
388 ret = __kfifo_to_user_data(fifo, to, reclen, recsize, &total);
389
390 if (likely(ret == 0))
391 __kfifo_add_out(fifo, reclen + recsize);
392
393 return total;
394}
395EXPORT_SYMBOL(__kfifo_to_user_n);
396
397/**
398 * kfifo_to_user - gets data from the FIFO and write it to user space
399 * @fifo: the fifo to be used.
400 * @to: where the data must be copied.
401 * @len: the size of the destination buffer.
402 @ @lenout: pointer to output variable with copied data
403 *
404 * This function copies at most @len bytes from the FIFO into the
405 * @to buffer and 0 or -EFAULT.
406 *
407 * Note that with only one concurrent reader and one concurrent
408 * writer, you don't need extra locking to use these functions.
409 */
410int kfifo_to_user(struct kfifo *fifo,
411 void __user *to, unsigned int len, unsigned *lenout)
412{
413 int ret;
414 len = min(kfifo_len(fifo), len);
415 ret = __kfifo_to_user_data(fifo, to, len, 0, lenout);
416 __kfifo_add_out(fifo, *lenout);
417 return ret;
418}
419EXPORT_SYMBOL(kfifo_to_user);
420
421unsigned int __kfifo_to_user_generic(struct kfifo *fifo,
422 void __user *to, unsigned int len, unsigned int recsize,
423 unsigned int *total)
424{
425 return __kfifo_to_user_rec(fifo, to, len, recsize, total);
426}
427EXPORT_SYMBOL(__kfifo_to_user_generic);
428
429unsigned int __kfifo_peek_generic(struct kfifo *fifo, unsigned int recsize)
430{
431 if (recsize == 0)
432 return kfifo_avail(fifo);
433
434 return __kfifo_peek_n(fifo, recsize);
435}
436EXPORT_SYMBOL(__kfifo_peek_generic);
437
438void __kfifo_skip_generic(struct kfifo *fifo, unsigned int recsize)
439{
440 __kfifo_skip_rec(fifo, recsize);
441}
442EXPORT_SYMBOL(__kfifo_skip_generic);
443