2 * ring_buffer_backend.c
4 * Copyright (C) 2005-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; only
9 * version 2.1 of the License.
11 * This library 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 GNU
14 * Lesser General Public License for more details.
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with this library; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 #include <linux/stddef.h>
22 #include <linux/module.h>
23 #include <linux/string.h>
24 #include <linux/bitops.h>
25 #include <linux/delay.h>
26 #include <linux/errno.h>
27 #include <linux/slab.h>
28 #include <linux/cpu.h>
30 #include <linux/vmalloc.h>
32 #include <wrapper/vmalloc.h> /* for wrapper_vmalloc_sync_all() */
33 #include <wrapper/ringbuffer/config.h>
34 #include <wrapper/ringbuffer/backend.h>
35 #include <wrapper/ringbuffer/frontend.h>
38 * lib_ring_buffer_backend_allocate - allocate a channel buffer
39 * @config: ring buffer instance configuration
40 * @buf: the buffer struct
41 * @size: total size of the buffer
42 * @num_subbuf: number of subbuffers
43 * @extra_reader_sb: need extra subbuffer for reader
46 int lib_ring_buffer_backend_allocate(const struct lib_ring_buffer_config
*config
,
47 struct lib_ring_buffer_backend
*bufb
,
48 size_t size
, size_t num_subbuf
,
51 struct channel_backend
*chanb
= &bufb
->chan
->backend
;
52 unsigned long j
, num_pages
, num_pages_per_subbuf
, page_idx
= 0;
53 unsigned long subbuf_size
, mmap_offset
= 0;
54 unsigned long num_subbuf_alloc
;
58 num_pages
= size
>> PAGE_SHIFT
;
59 num_pages_per_subbuf
= num_pages
>> get_count_order(num_subbuf
);
60 subbuf_size
= chanb
->subbuf_size
;
61 num_subbuf_alloc
= num_subbuf
;
63 if (extra_reader_sb
) {
64 num_pages
+= num_pages_per_subbuf
; /* Add pages for reader */
68 pages
= vmalloc_node(ALIGN(sizeof(*pages
) * num_pages
,
69 1 << INTERNODE_CACHE_SHIFT
),
70 cpu_to_node(max(bufb
->cpu
, 0)));
74 bufb
->array
= kmalloc_node(ALIGN(sizeof(*bufb
->array
)
76 1 << INTERNODE_CACHE_SHIFT
),
77 GFP_KERNEL
| __GFP_NOWARN
,
78 cpu_to_node(max(bufb
->cpu
, 0)));
79 if (unlikely(!bufb
->array
))
82 for (i
= 0; i
< num_pages
; i
++) {
83 pages
[i
] = alloc_pages_node(cpu_to_node(max(bufb
->cpu
, 0)),
84 GFP_KERNEL
| __GFP_NOWARN
| __GFP_ZERO
, 0);
85 if (unlikely(!pages
[i
]))
88 bufb
->num_pages_per_subbuf
= num_pages_per_subbuf
;
90 /* Allocate backend pages array elements */
91 for (i
= 0; i
< num_subbuf_alloc
; i
++) {
94 sizeof(struct lib_ring_buffer_backend_pages
) +
95 sizeof(struct lib_ring_buffer_backend_page
)
96 * num_pages_per_subbuf
,
97 1 << INTERNODE_CACHE_SHIFT
),
98 GFP_KERNEL
| __GFP_NOWARN
,
99 cpu_to_node(max(bufb
->cpu
, 0)));
104 /* Allocate write-side subbuffer table */
105 bufb
->buf_wsb
= kzalloc_node(ALIGN(
106 sizeof(struct lib_ring_buffer_backend_subbuffer
)
108 1 << INTERNODE_CACHE_SHIFT
),
109 GFP_KERNEL
| __GFP_NOWARN
,
110 cpu_to_node(max(bufb
->cpu
, 0)));
111 if (unlikely(!bufb
->buf_wsb
))
114 for (i
= 0; i
< num_subbuf
; i
++)
115 bufb
->buf_wsb
[i
].id
= subbuffer_id(config
, 0, 1, i
);
117 /* Assign read-side subbuffer table */
119 bufb
->buf_rsb
.id
= subbuffer_id(config
, 0, 1,
120 num_subbuf_alloc
- 1);
122 bufb
->buf_rsb
.id
= subbuffer_id(config
, 0, 1, 0);
124 /* Allocate subbuffer packet counter table */
125 bufb
->buf_cnt
= kzalloc_node(ALIGN(
126 sizeof(struct lib_ring_buffer_backend_counts
)
128 1 << INTERNODE_CACHE_SHIFT
),
129 GFP_KERNEL
| __GFP_NOWARN
,
130 cpu_to_node(max(bufb
->cpu
, 0)));
131 if (unlikely(!bufb
->buf_cnt
))
134 /* Assign pages to page index */
135 for (i
= 0; i
< num_subbuf_alloc
; i
++) {
136 for (j
= 0; j
< num_pages_per_subbuf
; j
++) {
137 CHAN_WARN_ON(chanb
, page_idx
> num_pages
);
138 bufb
->array
[i
]->p
[j
].virt
= page_address(pages
[page_idx
]);
139 bufb
->array
[i
]->p
[j
].pfn
= page_to_pfn(pages
[page_idx
]);
142 if (config
->output
== RING_BUFFER_MMAP
) {
143 bufb
->array
[i
]->mmap_offset
= mmap_offset
;
144 mmap_offset
+= subbuf_size
;
149 * If kmalloc ever uses vmalloc underneath, make sure the buffer pages
152 wrapper_vmalloc_sync_all();
157 kfree(bufb
->buf_wsb
);
159 for (i
= 0; (i
< num_subbuf_alloc
&& bufb
->array
[i
]); i
++)
160 kfree(bufb
->array
[i
]);
162 /* Free all allocated pages */
163 for (i
= 0; (i
< num_pages
&& pages
[i
]); i
++)
164 __free_page(pages
[i
]);
172 int lib_ring_buffer_backend_create(struct lib_ring_buffer_backend
*bufb
,
173 struct channel_backend
*chanb
, int cpu
)
175 const struct lib_ring_buffer_config
*config
= &chanb
->config
;
177 bufb
->chan
= container_of(chanb
, struct channel
, backend
);
180 return lib_ring_buffer_backend_allocate(config
, bufb
, chanb
->buf_size
,
182 chanb
->extra_reader_sb
);
185 void lib_ring_buffer_backend_free(struct lib_ring_buffer_backend
*bufb
)
187 struct channel_backend
*chanb
= &bufb
->chan
->backend
;
188 unsigned long i
, j
, num_subbuf_alloc
;
190 num_subbuf_alloc
= chanb
->num_subbuf
;
191 if (chanb
->extra_reader_sb
)
194 kfree(bufb
->buf_wsb
);
195 kfree(bufb
->buf_cnt
);
196 for (i
= 0; i
< num_subbuf_alloc
; i
++) {
197 for (j
= 0; j
< bufb
->num_pages_per_subbuf
; j
++)
198 __free_page(pfn_to_page(bufb
->array
[i
]->p
[j
].pfn
));
199 kfree(bufb
->array
[i
]);
205 void lib_ring_buffer_backend_reset(struct lib_ring_buffer_backend
*bufb
)
207 struct channel_backend
*chanb
= &bufb
->chan
->backend
;
208 const struct lib_ring_buffer_config
*config
= &chanb
->config
;
209 unsigned long num_subbuf_alloc
;
212 num_subbuf_alloc
= chanb
->num_subbuf
;
213 if (chanb
->extra_reader_sb
)
216 for (i
= 0; i
< chanb
->num_subbuf
; i
++)
217 bufb
->buf_wsb
[i
].id
= subbuffer_id(config
, 0, 1, i
);
218 if (chanb
->extra_reader_sb
)
219 bufb
->buf_rsb
.id
= subbuffer_id(config
, 0, 1,
220 num_subbuf_alloc
- 1);
222 bufb
->buf_rsb
.id
= subbuffer_id(config
, 0, 1, 0);
224 for (i
= 0; i
< num_subbuf_alloc
; i
++) {
225 /* Don't reset mmap_offset */
226 v_set(config
, &bufb
->array
[i
]->records_commit
, 0);
227 v_set(config
, &bufb
->array
[i
]->records_unread
, 0);
228 bufb
->array
[i
]->data_size
= 0;
229 /* Don't reset backend page and virt addresses */
231 /* Don't reset num_pages_per_subbuf, cpu, allocated */
232 v_set(config
, &bufb
->records_read
, 0);
236 * The frontend is responsible for also calling ring_buffer_backend_reset for
237 * each buffer when calling channel_backend_reset.
239 void channel_backend_reset(struct channel_backend
*chanb
)
241 struct channel
*chan
= container_of(chanb
, struct channel
, backend
);
242 const struct lib_ring_buffer_config
*config
= &chanb
->config
;
245 * Don't reset buf_size, subbuf_size, subbuf_size_order,
246 * num_subbuf_order, buf_size_order, extra_reader_sb, num_subbuf,
247 * priv, notifiers, config, cpumask and name.
249 chanb
->start_tsc
= config
->cb
.ring_buffer_clock_read(chan
);
252 #ifdef CONFIG_HOTPLUG_CPU
254 * lib_ring_buffer_cpu_hp_callback - CPU hotplug callback
255 * @nb: notifier block
256 * @action: hotplug action to take
259 * Returns the success/failure of the operation. (%NOTIFY_OK, %NOTIFY_BAD)
262 int lib_ring_buffer_cpu_hp_callback(struct notifier_block
*nb
,
263 unsigned long action
,
266 unsigned int cpu
= (unsigned long)hcpu
;
267 struct channel_backend
*chanb
= container_of(nb
, struct channel_backend
,
269 const struct lib_ring_buffer_config
*config
= &chanb
->config
;
270 struct lib_ring_buffer
*buf
;
273 CHAN_WARN_ON(chanb
, config
->alloc
== RING_BUFFER_ALLOC_GLOBAL
);
277 case CPU_UP_PREPARE_FROZEN
:
278 buf
= per_cpu_ptr(chanb
->buf
, cpu
);
279 ret
= lib_ring_buffer_create(buf
, chanb
, cpu
);
282 "ring_buffer_cpu_hp_callback: cpu %d "
283 "buffer creation failed\n", cpu
);
288 case CPU_DEAD_FROZEN
:
289 /* No need to do a buffer switch here, because it will happen
290 * when tracing is stopped, or will be done by switch timer CPU
299 * channel_backend_init - initialize a channel backend
300 * @chanb: channel backend
301 * @name: channel name
302 * @config: client ring buffer configuration
303 * @priv: client private data
304 * @parent: dentry of parent directory, %NULL for root directory
305 * @subbuf_size: size of sub-buffers (> PAGE_SIZE, power of 2)
306 * @num_subbuf: number of sub-buffers (power of 2)
308 * Returns channel pointer if successful, %NULL otherwise.
310 * Creates per-cpu channel buffers using the sizes and attributes
311 * specified. The created channel buffer files will be named
312 * name_0...name_N-1. File permissions will be %S_IRUSR.
314 * Called with CPU hotplug disabled.
316 int channel_backend_init(struct channel_backend
*chanb
,
318 const struct lib_ring_buffer_config
*config
,
319 void *priv
, size_t subbuf_size
, size_t num_subbuf
)
321 struct channel
*chan
= container_of(chanb
, struct channel
, backend
);
328 /* Check that the subbuffer size is larger than a page. */
329 if (subbuf_size
< PAGE_SIZE
)
333 * Make sure the number of subbuffers and subbuffer size are
334 * power of 2 and nonzero.
336 if (!subbuf_size
|| (subbuf_size
& (subbuf_size
- 1)))
338 if (!num_subbuf
|| (num_subbuf
& (num_subbuf
- 1)))
341 * Overwrite mode buffers require at least 2 subbuffers per
344 if (config
->mode
== RING_BUFFER_OVERWRITE
&& num_subbuf
< 2)
347 ret
= subbuffer_id_check_index(config
, num_subbuf
);
352 chanb
->buf_size
= num_subbuf
* subbuf_size
;
353 chanb
->subbuf_size
= subbuf_size
;
354 chanb
->buf_size_order
= get_count_order(chanb
->buf_size
);
355 chanb
->subbuf_size_order
= get_count_order(subbuf_size
);
356 chanb
->num_subbuf_order
= get_count_order(num_subbuf
);
357 chanb
->extra_reader_sb
=
358 (config
->mode
== RING_BUFFER_OVERWRITE
) ? 1 : 0;
359 chanb
->num_subbuf
= num_subbuf
;
360 strlcpy(chanb
->name
, name
, NAME_MAX
);
361 memcpy(&chanb
->config
, config
, sizeof(chanb
->config
));
363 if (config
->alloc
== RING_BUFFER_ALLOC_PER_CPU
) {
364 if (!zalloc_cpumask_var(&chanb
->cpumask
, GFP_KERNEL
))
368 if (config
->alloc
== RING_BUFFER_ALLOC_PER_CPU
) {
369 /* Allocating the buffer per-cpu structures */
370 chanb
->buf
= alloc_percpu(struct lib_ring_buffer
);
375 * In case of non-hotplug cpu, if the ring-buffer is allocated
376 * in early initcall, it will not be notified of secondary cpus.
377 * In that off case, we need to allocate for all possible cpus.
379 #ifdef CONFIG_HOTPLUG_CPU
381 * buf->backend.allocated test takes care of concurrent CPU
383 * Priority higher than frontend, so we create the ring buffer
384 * before we start the timer.
386 chanb
->cpu_hp_notifier
.notifier_call
=
387 lib_ring_buffer_cpu_hp_callback
;
388 chanb
->cpu_hp_notifier
.priority
= 5;
389 register_hotcpu_notifier(&chanb
->cpu_hp_notifier
);
392 for_each_online_cpu(i
) {
393 ret
= lib_ring_buffer_create(per_cpu_ptr(chanb
->buf
, i
),
396 goto free_bufs
; /* cpu hotplug locked */
400 for_each_possible_cpu(i
) {
401 ret
= lib_ring_buffer_create(per_cpu_ptr(chanb
->buf
, i
),
404 goto free_bufs
; /* cpu hotplug locked */
408 chanb
->buf
= kzalloc(sizeof(struct lib_ring_buffer
), GFP_KERNEL
);
411 ret
= lib_ring_buffer_create(chanb
->buf
, chanb
, -1);
415 chanb
->start_tsc
= config
->cb
.ring_buffer_clock_read(chan
);
420 if (config
->alloc
== RING_BUFFER_ALLOC_PER_CPU
) {
421 for_each_possible_cpu(i
) {
422 struct lib_ring_buffer
*buf
= per_cpu_ptr(chanb
->buf
, i
);
424 if (!buf
->backend
.allocated
)
426 lib_ring_buffer_free(buf
);
428 #ifdef CONFIG_HOTPLUG_CPU
430 unregister_hotcpu_notifier(&chanb
->cpu_hp_notifier
);
432 free_percpu(chanb
->buf
);
436 if (config
->alloc
== RING_BUFFER_ALLOC_PER_CPU
)
437 free_cpumask_var(chanb
->cpumask
);
442 * channel_backend_unregister_notifiers - unregister notifiers
447 void channel_backend_unregister_notifiers(struct channel_backend
*chanb
)
449 const struct lib_ring_buffer_config
*config
= &chanb
->config
;
451 if (config
->alloc
== RING_BUFFER_ALLOC_PER_CPU
)
452 unregister_hotcpu_notifier(&chanb
->cpu_hp_notifier
);
456 * channel_backend_free - destroy the channel
459 * Destroy all channel buffers and frees the channel.
461 void channel_backend_free(struct channel_backend
*chanb
)
463 const struct lib_ring_buffer_config
*config
= &chanb
->config
;
466 if (config
->alloc
== RING_BUFFER_ALLOC_PER_CPU
) {
467 for_each_possible_cpu(i
) {
468 struct lib_ring_buffer
*buf
= per_cpu_ptr(chanb
->buf
, i
);
470 if (!buf
->backend
.allocated
)
472 lib_ring_buffer_free(buf
);
474 free_cpumask_var(chanb
->cpumask
);
475 free_percpu(chanb
->buf
);
477 struct lib_ring_buffer
*buf
= chanb
->buf
;
479 CHAN_WARN_ON(chanb
, !buf
->backend
.allocated
);
480 lib_ring_buffer_free(buf
);
486 * lib_ring_buffer_write - write data to a ring_buffer buffer.
487 * @bufb : buffer backend
488 * @offset : offset within the buffer
489 * @src : source address
490 * @len : length to write
491 * @pagecpy : page size copied so far
493 void _lib_ring_buffer_write(struct lib_ring_buffer_backend
*bufb
, size_t offset
,
494 const void *src
, size_t len
, size_t pagecpy
)
496 struct channel_backend
*chanb
= &bufb
->chan
->backend
;
497 const struct lib_ring_buffer_config
*config
= &chanb
->config
;
499 struct lib_ring_buffer_backend_pages
*rpages
;
500 unsigned long sb_bindex
, id
;
506 sbidx
= offset
>> chanb
->subbuf_size_order
;
507 index
= (offset
& (chanb
->subbuf_size
- 1)) >> PAGE_SHIFT
;
510 * Underlying layer should never ask for writes across
513 CHAN_WARN_ON(chanb
, offset
>= chanb
->buf_size
);
515 pagecpy
= min_t(size_t, len
, PAGE_SIZE
- (offset
& ~PAGE_MASK
));
516 id
= bufb
->buf_wsb
[sbidx
].id
;
517 sb_bindex
= subbuffer_id_get_index(config
, id
);
518 rpages
= bufb
->array
[sb_bindex
];
519 CHAN_WARN_ON(chanb
, config
->mode
== RING_BUFFER_OVERWRITE
520 && subbuffer_id_is_noref(config
, id
));
521 lib_ring_buffer_do_copy(config
,
522 rpages
->p
[index
].virt
523 + (offset
& ~PAGE_MASK
),
525 } while (unlikely(len
!= pagecpy
));
527 EXPORT_SYMBOL_GPL(_lib_ring_buffer_write
);
531 * lib_ring_buffer_memset - write len bytes of c to a ring_buffer buffer.
532 * @bufb : buffer backend
533 * @offset : offset within the buffer
534 * @c : the byte to write
535 * @len : length to write
536 * @pagecpy : page size copied so far
538 void _lib_ring_buffer_memset(struct lib_ring_buffer_backend
*bufb
,
540 int c
, size_t len
, size_t pagecpy
)
542 struct channel_backend
*chanb
= &bufb
->chan
->backend
;
543 const struct lib_ring_buffer_config
*config
= &chanb
->config
;
545 struct lib_ring_buffer_backend_pages
*rpages
;
546 unsigned long sb_bindex
, id
;
551 sbidx
= offset
>> chanb
->subbuf_size_order
;
552 index
= (offset
& (chanb
->subbuf_size
- 1)) >> PAGE_SHIFT
;
555 * Underlying layer should never ask for writes across
558 CHAN_WARN_ON(chanb
, offset
>= chanb
->buf_size
);
560 pagecpy
= min_t(size_t, len
, PAGE_SIZE
- (offset
& ~PAGE_MASK
));
561 id
= bufb
->buf_wsb
[sbidx
].id
;
562 sb_bindex
= subbuffer_id_get_index(config
, id
);
563 rpages
= bufb
->array
[sb_bindex
];
564 CHAN_WARN_ON(chanb
, config
->mode
== RING_BUFFER_OVERWRITE
565 && subbuffer_id_is_noref(config
, id
));
566 lib_ring_buffer_do_memset(rpages
->p
[index
].virt
567 + (offset
& ~PAGE_MASK
),
569 } while (unlikely(len
!= pagecpy
));
571 EXPORT_SYMBOL_GPL(_lib_ring_buffer_memset
);
574 * lib_ring_buffer_strcpy - write string data to a ring_buffer buffer.
575 * @bufb : buffer backend
576 * @offset : offset within the buffer
577 * @src : source address
578 * @len : length to write
579 * @pagecpy : page size copied so far
580 * @pad : character to use for padding
582 void _lib_ring_buffer_strcpy(struct lib_ring_buffer_backend
*bufb
,
583 size_t offset
, const char *src
, size_t len
,
584 size_t pagecpy
, int pad
)
586 struct channel_backend
*chanb
= &bufb
->chan
->backend
;
587 const struct lib_ring_buffer_config
*config
= &chanb
->config
;
589 struct lib_ring_buffer_backend_pages
*rpages
;
590 unsigned long sb_bindex
, id
;
591 int src_terminated
= 0;
593 CHAN_WARN_ON(chanb
, !len
);
599 sbidx
= offset
>> chanb
->subbuf_size_order
;
600 index
= (offset
& (chanb
->subbuf_size
- 1)) >> PAGE_SHIFT
;
603 * Underlying layer should never ask for writes across
606 CHAN_WARN_ON(chanb
, offset
>= chanb
->buf_size
);
608 pagecpy
= min_t(size_t, len
, PAGE_SIZE
- (offset
& ~PAGE_MASK
));
609 id
= bufb
->buf_wsb
[sbidx
].id
;
610 sb_bindex
= subbuffer_id_get_index(config
, id
);
611 rpages
= bufb
->array
[sb_bindex
];
612 CHAN_WARN_ON(chanb
, config
->mode
== RING_BUFFER_OVERWRITE
613 && subbuffer_id_is_noref(config
, id
));
615 if (likely(!src_terminated
)) {
616 size_t count
, to_copy
;
620 to_copy
--; /* Final '\0' */
621 count
= lib_ring_buffer_do_strcpy(config
,
622 rpages
->p
[index
].virt
623 + (offset
& ~PAGE_MASK
),
627 if (unlikely(count
< to_copy
)) {
628 size_t pad_len
= to_copy
- count
;
630 /* Next pages will have padding */
632 lib_ring_buffer_do_memset(rpages
->p
[index
].virt
633 + (offset
& ~PAGE_MASK
),
642 pad_len
--; /* Final '\0' */
643 lib_ring_buffer_do_memset(rpages
->p
[index
].virt
644 + (offset
& ~PAGE_MASK
),
648 } while (unlikely(len
!= pagecpy
));
650 lib_ring_buffer_do_memset(rpages
->p
[index
].virt
+ (offset
& ~PAGE_MASK
),
653 EXPORT_SYMBOL_GPL(_lib_ring_buffer_strcpy
);
656 * lib_ring_buffer_copy_from_user_inatomic - write user data to a ring_buffer buffer.
657 * @bufb : buffer backend
658 * @offset : offset within the buffer
659 * @src : source address
660 * @len : length to write
661 * @pagecpy : page size copied so far
663 * This function deals with userspace pointers, it should never be called
664 * directly without having the src pointer checked with access_ok()
667 void _lib_ring_buffer_copy_from_user_inatomic(struct lib_ring_buffer_backend
*bufb
,
669 const void __user
*src
, size_t len
,
672 struct channel_backend
*chanb
= &bufb
->chan
->backend
;
673 const struct lib_ring_buffer_config
*config
= &chanb
->config
;
675 struct lib_ring_buffer_backend_pages
*rpages
;
676 unsigned long sb_bindex
, id
;
683 sbidx
= offset
>> chanb
->subbuf_size_order
;
684 index
= (offset
& (chanb
->subbuf_size
- 1)) >> PAGE_SHIFT
;
687 * Underlying layer should never ask for writes across
690 CHAN_WARN_ON(chanb
, offset
>= chanb
->buf_size
);
692 pagecpy
= min_t(size_t, len
, PAGE_SIZE
- (offset
& ~PAGE_MASK
));
693 id
= bufb
->buf_wsb
[sbidx
].id
;
694 sb_bindex
= subbuffer_id_get_index(config
, id
);
695 rpages
= bufb
->array
[sb_bindex
];
696 CHAN_WARN_ON(chanb
, config
->mode
== RING_BUFFER_OVERWRITE
697 && subbuffer_id_is_noref(config
, id
));
698 ret
= lib_ring_buffer_do_copy_from_user_inatomic(rpages
->p
[index
].virt
699 + (offset
& ~PAGE_MASK
),
703 _lib_ring_buffer_memset(bufb
, offset
, 0, len
, 0);
704 break; /* stop copy */
706 } while (unlikely(len
!= pagecpy
));
708 EXPORT_SYMBOL_GPL(_lib_ring_buffer_copy_from_user_inatomic
);
711 * lib_ring_buffer_strcpy_from_user_inatomic - write userspace string data to a ring_buffer buffer.
712 * @bufb : buffer backend
713 * @offset : offset within the buffer
714 * @src : source address
715 * @len : length to write
716 * @pagecpy : page size copied so far
717 * @pad : character to use for padding
719 * This function deals with userspace pointers, it should never be called
720 * directly without having the src pointer checked with access_ok()
723 void _lib_ring_buffer_strcpy_from_user_inatomic(struct lib_ring_buffer_backend
*bufb
,
724 size_t offset
, const char __user
*src
, size_t len
,
725 size_t pagecpy
, int pad
)
727 struct channel_backend
*chanb
= &bufb
->chan
->backend
;
728 const struct lib_ring_buffer_config
*config
= &chanb
->config
;
730 struct lib_ring_buffer_backend_pages
*rpages
;
731 unsigned long sb_bindex
, id
;
732 int src_terminated
= 0;
739 sbidx
= offset
>> chanb
->subbuf_size_order
;
740 index
= (offset
& (chanb
->subbuf_size
- 1)) >> PAGE_SHIFT
;
743 * Underlying layer should never ask for writes across
746 CHAN_WARN_ON(chanb
, offset
>= chanb
->buf_size
);
748 pagecpy
= min_t(size_t, len
, PAGE_SIZE
- (offset
& ~PAGE_MASK
));
749 id
= bufb
->buf_wsb
[sbidx
].id
;
750 sb_bindex
= subbuffer_id_get_index(config
, id
);
751 rpages
= bufb
->array
[sb_bindex
];
752 CHAN_WARN_ON(chanb
, config
->mode
== RING_BUFFER_OVERWRITE
753 && subbuffer_id_is_noref(config
, id
));
755 if (likely(!src_terminated
)) {
756 size_t count
, to_copy
;
760 to_copy
--; /* Final '\0' */
761 count
= lib_ring_buffer_do_strcpy_from_user_inatomic(config
,
762 rpages
->p
[index
].virt
763 + (offset
& ~PAGE_MASK
),
767 if (unlikely(count
< to_copy
)) {
768 size_t pad_len
= to_copy
- count
;
770 /* Next pages will have padding */
772 lib_ring_buffer_do_memset(rpages
->p
[index
].virt
773 + (offset
& ~PAGE_MASK
),
782 pad_len
--; /* Final '\0' */
783 lib_ring_buffer_do_memset(rpages
->p
[index
].virt
784 + (offset
& ~PAGE_MASK
),
788 } while (unlikely(len
!= pagecpy
));
790 lib_ring_buffer_do_memset(rpages
->p
[index
].virt
+ (offset
& ~PAGE_MASK
),
793 EXPORT_SYMBOL_GPL(_lib_ring_buffer_strcpy_from_user_inatomic
);
796 * lib_ring_buffer_read - read data from ring_buffer_buffer.
797 * @bufb : buffer backend
798 * @offset : offset within the buffer
799 * @dest : destination address
800 * @len : length to copy to destination
802 * Should be protected by get_subbuf/put_subbuf.
803 * Returns the length copied.
805 size_t lib_ring_buffer_read(struct lib_ring_buffer_backend
*bufb
, size_t offset
,
806 void *dest
, size_t len
)
808 struct channel_backend
*chanb
= &bufb
->chan
->backend
;
809 const struct lib_ring_buffer_config
*config
= &chanb
->config
;
810 size_t index
, pagecpy
, orig_len
;
811 struct lib_ring_buffer_backend_pages
*rpages
;
812 unsigned long sb_bindex
, id
;
815 offset
&= chanb
->buf_size
- 1;
816 index
= (offset
& (chanb
->subbuf_size
- 1)) >> PAGE_SHIFT
;
820 pagecpy
= min_t(size_t, len
, PAGE_SIZE
- (offset
& ~PAGE_MASK
));
821 id
= bufb
->buf_rsb
.id
;
822 sb_bindex
= subbuffer_id_get_index(config
, id
);
823 rpages
= bufb
->array
[sb_bindex
];
824 CHAN_WARN_ON(chanb
, config
->mode
== RING_BUFFER_OVERWRITE
825 && subbuffer_id_is_noref(config
, id
));
826 memcpy(dest
, rpages
->p
[index
].virt
+ (offset
& ~PAGE_MASK
),
833 index
= (offset
& (chanb
->subbuf_size
- 1)) >> PAGE_SHIFT
;
835 * Underlying layer should never ask for reads across
838 CHAN_WARN_ON(chanb
, offset
>= chanb
->buf_size
);
842 EXPORT_SYMBOL_GPL(lib_ring_buffer_read
);
845 * __lib_ring_buffer_copy_to_user - read data from ring_buffer to userspace
846 * @bufb : buffer backend
847 * @offset : offset within the buffer
848 * @dest : destination userspace address
849 * @len : length to copy to destination
851 * Should be protected by get_subbuf/put_subbuf.
852 * access_ok() must have been performed on dest addresses prior to call this
854 * Returns -EFAULT on error, 0 if ok.
856 int __lib_ring_buffer_copy_to_user(struct lib_ring_buffer_backend
*bufb
,
857 size_t offset
, void __user
*dest
, size_t len
)
859 struct channel_backend
*chanb
= &bufb
->chan
->backend
;
860 const struct lib_ring_buffer_config
*config
= &chanb
->config
;
863 struct lib_ring_buffer_backend_pages
*rpages
;
864 unsigned long sb_bindex
, id
;
866 offset
&= chanb
->buf_size
- 1;
867 index
= (offset
& (chanb
->subbuf_size
- 1)) >> PAGE_SHIFT
;
871 pagecpy
= min_t(size_t, len
, PAGE_SIZE
- (offset
& ~PAGE_MASK
));
872 id
= bufb
->buf_rsb
.id
;
873 sb_bindex
= subbuffer_id_get_index(config
, id
);
874 rpages
= bufb
->array
[sb_bindex
];
875 CHAN_WARN_ON(chanb
, config
->mode
== RING_BUFFER_OVERWRITE
876 && subbuffer_id_is_noref(config
, id
));
877 if (__copy_to_user(dest
,
878 rpages
->p
[index
].virt
+ (offset
& ~PAGE_MASK
),
886 index
= (offset
& (chanb
->subbuf_size
- 1)) >> PAGE_SHIFT
;
888 * Underlying layer should never ask for reads across
891 CHAN_WARN_ON(chanb
, offset
>= chanb
->buf_size
);
895 EXPORT_SYMBOL_GPL(__lib_ring_buffer_copy_to_user
);
898 * lib_ring_buffer_read_cstr - read a C-style string from ring_buffer.
899 * @bufb : buffer backend
900 * @offset : offset within the buffer
901 * @dest : destination address
902 * @len : destination's length
904 * Return string's length, or -EINVAL on error.
905 * Should be protected by get_subbuf/put_subbuf.
906 * Destination length should be at least 1 to hold '\0'.
908 int lib_ring_buffer_read_cstr(struct lib_ring_buffer_backend
*bufb
, size_t offset
,
909 void *dest
, size_t len
)
911 struct channel_backend
*chanb
= &bufb
->chan
->backend
;
912 const struct lib_ring_buffer_config
*config
= &chanb
->config
;
914 ssize_t pagecpy
, pagelen
, strpagelen
, orig_offset
;
916 struct lib_ring_buffer_backend_pages
*rpages
;
917 unsigned long sb_bindex
, id
;
919 offset
&= chanb
->buf_size
- 1;
920 index
= (offset
& (chanb
->subbuf_size
- 1)) >> PAGE_SHIFT
;
921 orig_offset
= offset
;
925 id
= bufb
->buf_rsb
.id
;
926 sb_bindex
= subbuffer_id_get_index(config
, id
);
927 rpages
= bufb
->array
[sb_bindex
];
928 CHAN_WARN_ON(chanb
, config
->mode
== RING_BUFFER_OVERWRITE
929 && subbuffer_id_is_noref(config
, id
));
930 str
= (char *)rpages
->p
[index
].virt
+ (offset
& ~PAGE_MASK
);
931 pagelen
= PAGE_SIZE
- (offset
& ~PAGE_MASK
);
932 strpagelen
= strnlen(str
, pagelen
);
934 pagecpy
= min_t(size_t, len
, strpagelen
);
936 memcpy(dest
, str
, pagecpy
);
941 offset
+= strpagelen
;
942 index
= (offset
& (chanb
->subbuf_size
- 1)) >> PAGE_SHIFT
;
943 if (strpagelen
< pagelen
)
946 * Underlying layer should never ask for reads across
949 CHAN_WARN_ON(chanb
, offset
>= chanb
->buf_size
);
952 ((char *)dest
)[0] = 0;
953 return offset
- orig_offset
;
955 EXPORT_SYMBOL_GPL(lib_ring_buffer_read_cstr
);
958 * lib_ring_buffer_read_get_pfn - Get a page frame number to read from
959 * @bufb : buffer backend
960 * @offset : offset within the buffer
961 * @virt : pointer to page address (output)
963 * Should be protected by get_subbuf/put_subbuf.
964 * Returns the pointer to the page frame number unsigned long.
966 unsigned long *lib_ring_buffer_read_get_pfn(struct lib_ring_buffer_backend
*bufb
,
967 size_t offset
, void ***virt
)
970 struct lib_ring_buffer_backend_pages
*rpages
;
971 struct channel_backend
*chanb
= &bufb
->chan
->backend
;
972 const struct lib_ring_buffer_config
*config
= &chanb
->config
;
973 unsigned long sb_bindex
, id
;
975 offset
&= chanb
->buf_size
- 1;
976 index
= (offset
& (chanb
->subbuf_size
- 1)) >> PAGE_SHIFT
;
977 id
= bufb
->buf_rsb
.id
;
978 sb_bindex
= subbuffer_id_get_index(config
, id
);
979 rpages
= bufb
->array
[sb_bindex
];
980 CHAN_WARN_ON(chanb
, config
->mode
== RING_BUFFER_OVERWRITE
981 && subbuffer_id_is_noref(config
, id
));
982 *virt
= &rpages
->p
[index
].virt
;
983 return &rpages
->p
[index
].pfn
;
985 EXPORT_SYMBOL_GPL(lib_ring_buffer_read_get_pfn
);
988 * lib_ring_buffer_read_offset_address - get address of a buffer location
989 * @bufb : buffer backend
990 * @offset : offset within the buffer.
992 * Return the address where a given offset is located (for read).
993 * Should be used to get the current subbuffer header pointer. Given we know
994 * it's never on a page boundary, it's safe to read/write directly
995 * from/to this address, as long as the read/write is never bigger than a
998 void *lib_ring_buffer_read_offset_address(struct lib_ring_buffer_backend
*bufb
,
1002 struct lib_ring_buffer_backend_pages
*rpages
;
1003 struct channel_backend
*chanb
= &bufb
->chan
->backend
;
1004 const struct lib_ring_buffer_config
*config
= &chanb
->config
;
1005 unsigned long sb_bindex
, id
;
1007 offset
&= chanb
->buf_size
- 1;
1008 index
= (offset
& (chanb
->subbuf_size
- 1)) >> PAGE_SHIFT
;
1009 id
= bufb
->buf_rsb
.id
;
1010 sb_bindex
= subbuffer_id_get_index(config
, id
);
1011 rpages
= bufb
->array
[sb_bindex
];
1012 CHAN_WARN_ON(chanb
, config
->mode
== RING_BUFFER_OVERWRITE
1013 && subbuffer_id_is_noref(config
, id
));
1014 return rpages
->p
[index
].virt
+ (offset
& ~PAGE_MASK
);
1016 EXPORT_SYMBOL_GPL(lib_ring_buffer_read_offset_address
);
1019 * lib_ring_buffer_offset_address - get address of a location within the buffer
1020 * @bufb : buffer backend
1021 * @offset : offset within the buffer.
1023 * Return the address where a given offset is located.
1024 * Should be used to get the current subbuffer header pointer. Given we know
1025 * it's always at the beginning of a page, it's safe to write directly to this
1026 * address, as long as the write is never bigger than a page size.
1028 void *lib_ring_buffer_offset_address(struct lib_ring_buffer_backend
*bufb
,
1031 size_t sbidx
, index
;
1032 struct lib_ring_buffer_backend_pages
*rpages
;
1033 struct channel_backend
*chanb
= &bufb
->chan
->backend
;
1034 const struct lib_ring_buffer_config
*config
= &chanb
->config
;
1035 unsigned long sb_bindex
, id
;
1037 offset
&= chanb
->buf_size
- 1;
1038 sbidx
= offset
>> chanb
->subbuf_size_order
;
1039 index
= (offset
& (chanb
->subbuf_size
- 1)) >> PAGE_SHIFT
;
1040 id
= bufb
->buf_wsb
[sbidx
].id
;
1041 sb_bindex
= subbuffer_id_get_index(config
, id
);
1042 rpages
= bufb
->array
[sb_bindex
];
1043 CHAN_WARN_ON(chanb
, config
->mode
== RING_BUFFER_OVERWRITE
1044 && subbuffer_id_is_noref(config
, id
));
1045 return rpages
->p
[index
].virt
+ (offset
& ~PAGE_MASK
);
1047 EXPORT_SYMBOL_GPL(lib_ring_buffer_offset_address
);