1 /* SPDX-License-Identifier: (GPL-2.0-only OR LGPL-2.1-only)
3 * ring_buffer_backend.c
5 * Copyright (C) 2005-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
8 #include <linux/stddef.h>
9 #include <linux/module.h>
10 #include <linux/string.h>
11 #include <linux/bitops.h>
12 #include <linux/delay.h>
13 #include <linux/errno.h>
14 #include <linux/slab.h>
15 #include <linux/cpu.h>
17 #include <linux/vmalloc.h>
18 #include <linux/oom.h>
20 #include <wrapper/ringbuffer/config.h>
21 #include <wrapper/ringbuffer/backend.h>
22 #include <wrapper/ringbuffer/frontend.h>
25 * lib_ring_buffer_backend_allocate - allocate a channel buffer
26 * @config: ring buffer instance configuration
27 * @buf: the buffer struct
28 * @size: total size of the buffer
29 * @num_subbuf: number of subbuffers
30 * @extra_reader_sb: need extra subbuffer for reader
33 int lib_ring_buffer_backend_allocate(const struct lib_ring_buffer_config
*config
,
34 struct lib_ring_buffer_backend
*bufb
,
35 size_t size
, size_t num_subbuf
,
38 struct channel_backend
*chanb
= &bufb
->chan
->backend
;
39 unsigned long j
, num_pages
, num_pages_per_subbuf
, page_idx
= 0;
40 unsigned long subbuf_size
, mmap_offset
= 0;
41 unsigned long num_subbuf_alloc
;
45 num_pages
= size
>> PAGE_SHIFT
;
48 * Verify that there is enough free pages available on the system for
49 * the current allocation request.
50 * wrapper_check_enough_free_pages uses si_mem_available() if available
51 * and returns if there should be enough free pages based on the
54 if (num_pages
>= si_mem_available())
55 goto not_enough_pages
;
58 * Set the current user thread as the first target of the OOM killer.
59 * If the estimate received by si_mem_available() was off, and we do
60 * end up running out of memory because of this buffer allocation, we
61 * want to kill the offending app first.
63 set_current_oom_origin();
65 num_pages_per_subbuf
= num_pages
>> get_count_order(num_subbuf
);
66 subbuf_size
= chanb
->subbuf_size
;
67 num_subbuf_alloc
= num_subbuf
;
69 if (extra_reader_sb
) {
70 num_pages
+= num_pages_per_subbuf
; /* Add pages for reader */
74 pages
= vmalloc_node(ALIGN(sizeof(*pages
) * num_pages
,
75 1 << INTERNODE_CACHE_SHIFT
),
76 cpu_to_node(max(bufb
->cpu
, 0)));
80 bufb
->array
= kvmalloc_node(ALIGN(sizeof(*bufb
->array
)
82 1 << INTERNODE_CACHE_SHIFT
),
83 GFP_KERNEL
| __GFP_NOWARN
,
84 cpu_to_node(max(bufb
->cpu
, 0)));
85 if (unlikely(!bufb
->array
))
87 for (i
= 0; i
< num_pages
; i
++) {
88 pages
[i
] = alloc_pages_node(cpu_to_node(max(bufb
->cpu
, 0)),
89 GFP_KERNEL
| __GFP_NOWARN
| __GFP_ZERO
, 0);
90 if (unlikely(!pages
[i
]))
93 bufb
->num_pages_per_subbuf
= num_pages_per_subbuf
;
95 /* Allocate backend pages array elements */
96 for (i
= 0; i
< num_subbuf_alloc
; i
++) {
99 sizeof(struct lib_ring_buffer_backend_pages
) +
100 sizeof(struct lib_ring_buffer_backend_page
)
101 * num_pages_per_subbuf
,
102 1 << INTERNODE_CACHE_SHIFT
),
103 GFP_KERNEL
| __GFP_NOWARN
,
104 cpu_to_node(max(bufb
->cpu
, 0)));
109 /* Allocate write-side subbuffer table */
110 bufb
->buf_wsb
= kvzalloc_node(ALIGN(
111 sizeof(struct lib_ring_buffer_backend_subbuffer
)
113 1 << INTERNODE_CACHE_SHIFT
),
114 GFP_KERNEL
| __GFP_NOWARN
,
115 cpu_to_node(max(bufb
->cpu
, 0)));
116 if (unlikely(!bufb
->buf_wsb
))
119 for (i
= 0; i
< num_subbuf
; i
++)
120 bufb
->buf_wsb
[i
].id
= subbuffer_id(config
, 0, 1, i
);
122 /* Assign read-side subbuffer table */
124 bufb
->buf_rsb
.id
= subbuffer_id(config
, 0, 1,
125 num_subbuf_alloc
- 1);
127 bufb
->buf_rsb
.id
= subbuffer_id(config
, 0, 1, 0);
129 /* Allocate subbuffer packet counter table */
130 bufb
->buf_cnt
= kvzalloc_node(ALIGN(
131 sizeof(struct lib_ring_buffer_backend_counts
)
133 1 << INTERNODE_CACHE_SHIFT
),
134 GFP_KERNEL
| __GFP_NOWARN
,
135 cpu_to_node(max(bufb
->cpu
, 0)));
136 if (unlikely(!bufb
->buf_cnt
))
139 /* Assign pages to page index */
140 for (i
= 0; i
< num_subbuf_alloc
; i
++) {
141 for (j
= 0; j
< num_pages_per_subbuf
; j
++) {
142 CHAN_WARN_ON(chanb
, page_idx
> num_pages
);
143 bufb
->array
[i
]->p
[j
].virt
= page_address(pages
[page_idx
]);
144 bufb
->array
[i
]->p
[j
].pfn
= page_to_pfn(pages
[page_idx
]);
147 if (config
->output
== RING_BUFFER_MMAP
) {
148 bufb
->array
[i
]->mmap_offset
= mmap_offset
;
149 mmap_offset
+= subbuf_size
;
153 clear_current_oom_origin();
158 kvfree(bufb
->buf_wsb
);
160 for (i
= 0; (i
< num_subbuf_alloc
&& bufb
->array
[i
]); i
++)
161 kvfree(bufb
->array
[i
]);
163 /* Free all allocated pages */
164 for (i
= 0; (i
< num_pages
&& pages
[i
]); i
++)
165 __free_page(pages
[i
]);
170 clear_current_oom_origin();
175 int lib_ring_buffer_backend_create(struct lib_ring_buffer_backend
*bufb
,
176 struct channel_backend
*chanb
, int cpu
)
178 const struct lib_ring_buffer_config
*config
= &chanb
->config
;
180 bufb
->chan
= container_of(chanb
, struct channel
, backend
);
183 return lib_ring_buffer_backend_allocate(config
, bufb
, chanb
->buf_size
,
185 chanb
->extra_reader_sb
);
188 void lib_ring_buffer_backend_free(struct lib_ring_buffer_backend
*bufb
)
190 struct channel_backend
*chanb
= &bufb
->chan
->backend
;
191 unsigned long i
, j
, num_subbuf_alloc
;
193 num_subbuf_alloc
= chanb
->num_subbuf
;
194 if (chanb
->extra_reader_sb
)
197 kvfree(bufb
->buf_wsb
);
198 kvfree(bufb
->buf_cnt
);
199 for (i
= 0; i
< num_subbuf_alloc
; i
++) {
200 for (j
= 0; j
< bufb
->num_pages_per_subbuf
; j
++)
201 __free_page(pfn_to_page(bufb
->array
[i
]->p
[j
].pfn
));
202 kvfree(bufb
->array
[i
]);
208 void lib_ring_buffer_backend_reset(struct lib_ring_buffer_backend
*bufb
)
210 struct channel_backend
*chanb
= &bufb
->chan
->backend
;
211 const struct lib_ring_buffer_config
*config
= &chanb
->config
;
212 unsigned long num_subbuf_alloc
;
215 num_subbuf_alloc
= chanb
->num_subbuf
;
216 if (chanb
->extra_reader_sb
)
219 for (i
= 0; i
< chanb
->num_subbuf
; i
++)
220 bufb
->buf_wsb
[i
].id
= subbuffer_id(config
, 0, 1, i
);
221 if (chanb
->extra_reader_sb
)
222 bufb
->buf_rsb
.id
= subbuffer_id(config
, 0, 1,
223 num_subbuf_alloc
- 1);
225 bufb
->buf_rsb
.id
= subbuffer_id(config
, 0, 1, 0);
227 for (i
= 0; i
< num_subbuf_alloc
; i
++) {
228 /* Don't reset mmap_offset */
229 v_set(config
, &bufb
->array
[i
]->records_commit
, 0);
230 v_set(config
, &bufb
->array
[i
]->records_unread
, 0);
231 bufb
->array
[i
]->data_size
= 0;
232 /* Don't reset backend page and virt addresses */
234 /* Don't reset num_pages_per_subbuf, cpu, allocated */
235 v_set(config
, &bufb
->records_read
, 0);
239 * The frontend is responsible for also calling ring_buffer_backend_reset for
240 * each buffer when calling channel_backend_reset.
242 void channel_backend_reset(struct channel_backend
*chanb
)
244 struct channel
*chan
= container_of(chanb
, struct channel
, backend
);
245 const struct lib_ring_buffer_config
*config
= &chanb
->config
;
248 * Don't reset buf_size, subbuf_size, subbuf_size_order,
249 * num_subbuf_order, buf_size_order, extra_reader_sb, num_subbuf,
250 * priv, notifiers, config, cpumask and name.
252 chanb
->start_tsc
= config
->cb
.ring_buffer_clock_read(chan
);
256 * No need to implement a "dead" callback to do a buffer switch here,
257 * because it will happen when tracing is stopped, or will be done by
258 * switch timer CPU DEAD callback.
259 * We don't free buffers when CPU go away, because it would make trace
260 * data vanish, which is unwanted.
262 int lttng_cpuhp_rb_backend_prepare(unsigned int cpu
,
263 struct lttng_cpuhp_node
*node
)
265 struct channel_backend
*chanb
= container_of(node
,
266 struct channel_backend
, cpuhp_prepare
);
267 const struct lib_ring_buffer_config
*config
= &chanb
->config
;
268 struct lib_ring_buffer
*buf
;
271 CHAN_WARN_ON(chanb
, config
->alloc
== RING_BUFFER_ALLOC_GLOBAL
);
273 buf
= per_cpu_ptr(chanb
->buf
, cpu
);
274 ret
= lib_ring_buffer_create(buf
, chanb
, cpu
);
277 "ring_buffer_cpu_hp_callback: cpu %d "
278 "buffer creation failed\n", cpu
);
283 EXPORT_SYMBOL_GPL(lttng_cpuhp_rb_backend_prepare
);
286 * channel_backend_init - initialize a channel backend
287 * @chanb: channel backend
288 * @name: channel name
289 * @config: client ring buffer configuration
290 * @priv: client private data
291 * @parent: dentry of parent directory, %NULL for root directory
292 * @subbuf_size: size of sub-buffers (> PAGE_SIZE, power of 2)
293 * @num_subbuf: number of sub-buffers (power of 2)
295 * Returns channel pointer if successful, %NULL otherwise.
297 * Creates per-cpu channel buffers using the sizes and attributes
298 * specified. The created channel buffer files will be named
299 * name_0...name_N-1. File permissions will be %S_IRUSR.
301 * Called with CPU hotplug disabled.
303 int channel_backend_init(struct channel_backend
*chanb
,
305 const struct lib_ring_buffer_config
*config
,
306 void *priv
, size_t subbuf_size
, size_t num_subbuf
)
308 struct channel
*chan
= container_of(chanb
, struct channel
, backend
);
315 /* Check that the subbuffer size is larger than a page. */
316 if (subbuf_size
< PAGE_SIZE
)
320 * Make sure the number of subbuffers and subbuffer size are
321 * power of 2 and nonzero.
323 if (!subbuf_size
|| (subbuf_size
& (subbuf_size
- 1)))
325 if (!num_subbuf
|| (num_subbuf
& (num_subbuf
- 1)))
328 * Overwrite mode buffers require at least 2 subbuffers per
331 if (config
->mode
== RING_BUFFER_OVERWRITE
&& num_subbuf
< 2)
334 ret
= subbuffer_id_check_index(config
, num_subbuf
);
339 chanb
->buf_size
= num_subbuf
* subbuf_size
;
340 chanb
->subbuf_size
= subbuf_size
;
341 chanb
->buf_size_order
= get_count_order(chanb
->buf_size
);
342 chanb
->subbuf_size_order
= get_count_order(subbuf_size
);
343 chanb
->num_subbuf_order
= get_count_order(num_subbuf
);
344 chanb
->extra_reader_sb
=
345 (config
->mode
== RING_BUFFER_OVERWRITE
) ? 1 : 0;
346 chanb
->num_subbuf
= num_subbuf
;
347 strlcpy(chanb
->name
, name
, NAME_MAX
);
348 memcpy(&chanb
->config
, config
, sizeof(chanb
->config
));
350 if (config
->alloc
== RING_BUFFER_ALLOC_PER_CPU
) {
351 if (!zalloc_cpumask_var(&chanb
->cpumask
, GFP_KERNEL
))
355 if (config
->alloc
== RING_BUFFER_ALLOC_PER_CPU
) {
356 /* Allocating the buffer per-cpu structures */
357 chanb
->buf
= alloc_percpu(struct lib_ring_buffer
);
361 chanb
->cpuhp_prepare
.component
= LTTNG_RING_BUFFER_BACKEND
;
362 ret
= cpuhp_state_add_instance(lttng_rb_hp_prepare
,
363 &chanb
->cpuhp_prepare
.node
);
367 chanb
->buf
= kzalloc(sizeof(struct lib_ring_buffer
), GFP_KERNEL
);
370 ret
= lib_ring_buffer_create(chanb
->buf
, chanb
, -1);
374 chanb
->start_tsc
= config
->cb
.ring_buffer_clock_read(chan
);
379 if (config
->alloc
== RING_BUFFER_ALLOC_PER_CPU
) {
381 * Teardown of lttng_rb_hp_prepare instance
382 * on "add" error is handled within cpu hotplug,
383 * no teardown to do from the caller.
385 for_each_possible_cpu(i
) {
386 struct lib_ring_buffer
*buf
=
387 per_cpu_ptr(chanb
->buf
, i
);
389 if (!buf
->backend
.allocated
)
391 lib_ring_buffer_free(buf
);
393 free_percpu(chanb
->buf
);
397 if (config
->alloc
== RING_BUFFER_ALLOC_PER_CPU
)
398 free_cpumask_var(chanb
->cpumask
);
403 * channel_backend_unregister_notifiers - unregister notifiers
408 void channel_backend_unregister_notifiers(struct channel_backend
*chanb
)
410 const struct lib_ring_buffer_config
*config
= &chanb
->config
;
412 if (config
->alloc
== RING_BUFFER_ALLOC_PER_CPU
) {
415 ret
= cpuhp_state_remove_instance(lttng_rb_hp_prepare
,
416 &chanb
->cpuhp_prepare
.node
);
422 * channel_backend_free - destroy the channel
425 * Destroy all channel buffers and frees the channel.
427 void channel_backend_free(struct channel_backend
*chanb
)
429 const struct lib_ring_buffer_config
*config
= &chanb
->config
;
432 if (config
->alloc
== RING_BUFFER_ALLOC_PER_CPU
) {
433 for_each_possible_cpu(i
) {
434 struct lib_ring_buffer
*buf
= per_cpu_ptr(chanb
->buf
, i
);
436 if (!buf
->backend
.allocated
)
438 lib_ring_buffer_free(buf
);
440 free_cpumask_var(chanb
->cpumask
);
441 free_percpu(chanb
->buf
);
443 struct lib_ring_buffer
*buf
= chanb
->buf
;
445 CHAN_WARN_ON(chanb
, !buf
->backend
.allocated
);
446 lib_ring_buffer_free(buf
);
452 * lib_ring_buffer_write - write data to a ring_buffer buffer.
453 * @bufb : buffer backend
454 * @offset : offset within the buffer
455 * @src : source address
456 * @len : length to write
457 * @pagecpy : page size copied so far
459 void _lib_ring_buffer_write(struct lib_ring_buffer_backend
*bufb
, size_t offset
,
460 const void *src
, size_t len
, size_t pagecpy
)
462 struct channel_backend
*chanb
= &bufb
->chan
->backend
;
463 const struct lib_ring_buffer_config
*config
= &chanb
->config
;
465 struct lib_ring_buffer_backend_pages
*rpages
;
466 unsigned long sb_bindex
, id
;
472 sbidx
= offset
>> chanb
->subbuf_size_order
;
473 index
= (offset
& (chanb
->subbuf_size
- 1)) >> PAGE_SHIFT
;
476 * Underlying layer should never ask for writes across
479 CHAN_WARN_ON(chanb
, offset
>= chanb
->buf_size
);
481 pagecpy
= min_t(size_t, len
, PAGE_SIZE
- (offset
& ~PAGE_MASK
));
482 id
= bufb
->buf_wsb
[sbidx
].id
;
483 sb_bindex
= subbuffer_id_get_index(config
, id
);
484 rpages
= bufb
->array
[sb_bindex
];
485 CHAN_WARN_ON(chanb
, config
->mode
== RING_BUFFER_OVERWRITE
486 && subbuffer_id_is_noref(config
, id
));
487 lib_ring_buffer_do_copy(config
,
488 rpages
->p
[index
].virt
489 + (offset
& ~PAGE_MASK
),
491 } while (unlikely(len
!= pagecpy
));
493 EXPORT_SYMBOL_GPL(_lib_ring_buffer_write
);
497 * lib_ring_buffer_memset - write len bytes of c to a ring_buffer buffer.
498 * @bufb : buffer backend
499 * @offset : offset within the buffer
500 * @c : the byte to write
501 * @len : length to write
502 * @pagecpy : page size copied so far
504 void _lib_ring_buffer_memset(struct lib_ring_buffer_backend
*bufb
,
506 int c
, size_t len
, size_t pagecpy
)
508 struct channel_backend
*chanb
= &bufb
->chan
->backend
;
509 const struct lib_ring_buffer_config
*config
= &chanb
->config
;
511 struct lib_ring_buffer_backend_pages
*rpages
;
512 unsigned long sb_bindex
, id
;
517 sbidx
= offset
>> chanb
->subbuf_size_order
;
518 index
= (offset
& (chanb
->subbuf_size
- 1)) >> PAGE_SHIFT
;
521 * Underlying layer should never ask for writes across
524 CHAN_WARN_ON(chanb
, offset
>= chanb
->buf_size
);
526 pagecpy
= min_t(size_t, len
, PAGE_SIZE
- (offset
& ~PAGE_MASK
));
527 id
= bufb
->buf_wsb
[sbidx
].id
;
528 sb_bindex
= subbuffer_id_get_index(config
, id
);
529 rpages
= bufb
->array
[sb_bindex
];
530 CHAN_WARN_ON(chanb
, config
->mode
== RING_BUFFER_OVERWRITE
531 && subbuffer_id_is_noref(config
, id
));
532 lib_ring_buffer_do_memset(rpages
->p
[index
].virt
533 + (offset
& ~PAGE_MASK
),
535 } while (unlikely(len
!= pagecpy
));
537 EXPORT_SYMBOL_GPL(_lib_ring_buffer_memset
);
540 * lib_ring_buffer_strcpy - write string data to a ring_buffer buffer.
541 * @bufb : buffer backend
542 * @offset : offset within the buffer
543 * @src : source address
544 * @len : length to write
545 * @pagecpy : page size copied so far
546 * @pad : character to use for padding
548 void _lib_ring_buffer_strcpy(struct lib_ring_buffer_backend
*bufb
,
549 size_t offset
, const char *src
, size_t len
,
550 size_t pagecpy
, int pad
)
552 struct channel_backend
*chanb
= &bufb
->chan
->backend
;
553 const struct lib_ring_buffer_config
*config
= &chanb
->config
;
555 struct lib_ring_buffer_backend_pages
*rpages
;
556 unsigned long sb_bindex
, id
;
557 int src_terminated
= 0;
559 CHAN_WARN_ON(chanb
, !len
);
565 sbidx
= offset
>> chanb
->subbuf_size_order
;
566 index
= (offset
& (chanb
->subbuf_size
- 1)) >> PAGE_SHIFT
;
569 * Underlying layer should never ask for writes across
572 CHAN_WARN_ON(chanb
, offset
>= chanb
->buf_size
);
574 pagecpy
= min_t(size_t, len
, PAGE_SIZE
- (offset
& ~PAGE_MASK
));
575 id
= bufb
->buf_wsb
[sbidx
].id
;
576 sb_bindex
= subbuffer_id_get_index(config
, id
);
577 rpages
= bufb
->array
[sb_bindex
];
578 CHAN_WARN_ON(chanb
, config
->mode
== RING_BUFFER_OVERWRITE
579 && subbuffer_id_is_noref(config
, id
));
581 if (likely(!src_terminated
)) {
582 size_t count
, to_copy
;
586 to_copy
--; /* Final '\0' */
587 count
= lib_ring_buffer_do_strcpy(config
,
588 rpages
->p
[index
].virt
589 + (offset
& ~PAGE_MASK
),
593 if (unlikely(count
< to_copy
)) {
594 size_t pad_len
= to_copy
- count
;
596 /* Next pages will have padding */
598 lib_ring_buffer_do_memset(rpages
->p
[index
].virt
599 + (offset
& ~PAGE_MASK
),
608 pad_len
--; /* Final '\0' */
609 lib_ring_buffer_do_memset(rpages
->p
[index
].virt
610 + (offset
& ~PAGE_MASK
),
614 } while (unlikely(len
!= pagecpy
));
616 lib_ring_buffer_do_memset(rpages
->p
[index
].virt
+ (offset
& ~PAGE_MASK
),
619 EXPORT_SYMBOL_GPL(_lib_ring_buffer_strcpy
);
622 * lib_ring_buffer_copy_from_user_inatomic - write user data to a ring_buffer buffer.
623 * @bufb : buffer backend
624 * @offset : offset within the buffer
625 * @src : source address
626 * @len : length to write
627 * @pagecpy : page size copied so far
629 * This function deals with userspace pointers, it should never be called
630 * directly without having the src pointer checked with access_ok()
633 void _lib_ring_buffer_copy_from_user_inatomic(struct lib_ring_buffer_backend
*bufb
,
635 const void __user
*src
, size_t len
,
638 struct channel_backend
*chanb
= &bufb
->chan
->backend
;
639 const struct lib_ring_buffer_config
*config
= &chanb
->config
;
641 struct lib_ring_buffer_backend_pages
*rpages
;
642 unsigned long sb_bindex
, id
;
649 sbidx
= offset
>> chanb
->subbuf_size_order
;
650 index
= (offset
& (chanb
->subbuf_size
- 1)) >> PAGE_SHIFT
;
653 * Underlying layer should never ask for writes across
656 CHAN_WARN_ON(chanb
, offset
>= chanb
->buf_size
);
658 pagecpy
= min_t(size_t, len
, PAGE_SIZE
- (offset
& ~PAGE_MASK
));
659 id
= bufb
->buf_wsb
[sbidx
].id
;
660 sb_bindex
= subbuffer_id_get_index(config
, id
);
661 rpages
= bufb
->array
[sb_bindex
];
662 CHAN_WARN_ON(chanb
, config
->mode
== RING_BUFFER_OVERWRITE
663 && subbuffer_id_is_noref(config
, id
));
664 ret
= lib_ring_buffer_do_copy_from_user_inatomic(rpages
->p
[index
].virt
665 + (offset
& ~PAGE_MASK
),
669 _lib_ring_buffer_memset(bufb
, offset
, 0, len
, 0);
670 break; /* stop copy */
672 } while (unlikely(len
!= pagecpy
));
674 EXPORT_SYMBOL_GPL(_lib_ring_buffer_copy_from_user_inatomic
);
677 * lib_ring_buffer_strcpy_from_user_inatomic - write userspace string data to a ring_buffer buffer.
678 * @bufb : buffer backend
679 * @offset : offset within the buffer
680 * @src : source address
681 * @len : length to write
682 * @pagecpy : page size copied so far
683 * @pad : character to use for padding
685 * This function deals with userspace pointers, it should never be called
686 * directly without having the src pointer checked with access_ok()
689 void _lib_ring_buffer_strcpy_from_user_inatomic(struct lib_ring_buffer_backend
*bufb
,
690 size_t offset
, const char __user
*src
, size_t len
,
691 size_t pagecpy
, int pad
)
693 struct channel_backend
*chanb
= &bufb
->chan
->backend
;
694 const struct lib_ring_buffer_config
*config
= &chanb
->config
;
696 struct lib_ring_buffer_backend_pages
*rpages
;
697 unsigned long sb_bindex
, id
;
698 int src_terminated
= 0;
705 sbidx
= offset
>> chanb
->subbuf_size_order
;
706 index
= (offset
& (chanb
->subbuf_size
- 1)) >> PAGE_SHIFT
;
709 * Underlying layer should never ask for writes across
712 CHAN_WARN_ON(chanb
, offset
>= chanb
->buf_size
);
714 pagecpy
= min_t(size_t, len
, PAGE_SIZE
- (offset
& ~PAGE_MASK
));
715 id
= bufb
->buf_wsb
[sbidx
].id
;
716 sb_bindex
= subbuffer_id_get_index(config
, id
);
717 rpages
= bufb
->array
[sb_bindex
];
718 CHAN_WARN_ON(chanb
, config
->mode
== RING_BUFFER_OVERWRITE
719 && subbuffer_id_is_noref(config
, id
));
721 if (likely(!src_terminated
)) {
722 size_t count
, to_copy
;
726 to_copy
--; /* Final '\0' */
727 count
= lib_ring_buffer_do_strcpy_from_user_inatomic(config
,
728 rpages
->p
[index
].virt
729 + (offset
& ~PAGE_MASK
),
733 if (unlikely(count
< to_copy
)) {
734 size_t pad_len
= to_copy
- count
;
736 /* Next pages will have padding */
738 lib_ring_buffer_do_memset(rpages
->p
[index
].virt
739 + (offset
& ~PAGE_MASK
),
748 pad_len
--; /* Final '\0' */
749 lib_ring_buffer_do_memset(rpages
->p
[index
].virt
750 + (offset
& ~PAGE_MASK
),
754 } while (unlikely(len
!= pagecpy
));
756 lib_ring_buffer_do_memset(rpages
->p
[index
].virt
+ (offset
& ~PAGE_MASK
),
759 EXPORT_SYMBOL_GPL(_lib_ring_buffer_strcpy_from_user_inatomic
);
762 * lib_ring_buffer_read - read data from ring_buffer_buffer.
763 * @bufb : buffer backend
764 * @offset : offset within the buffer
765 * @dest : destination address
766 * @len : length to copy to destination
768 * Should be protected by get_subbuf/put_subbuf.
769 * Returns the length copied.
771 size_t lib_ring_buffer_read(struct lib_ring_buffer_backend
*bufb
, size_t offset
,
772 void *dest
, size_t len
)
774 struct channel_backend
*chanb
= &bufb
->chan
->backend
;
775 const struct lib_ring_buffer_config
*config
= &chanb
->config
;
776 size_t index
, pagecpy
, orig_len
;
777 struct lib_ring_buffer_backend_pages
*rpages
;
778 unsigned long sb_bindex
, id
;
781 offset
&= chanb
->buf_size
- 1;
782 index
= (offset
& (chanb
->subbuf_size
- 1)) >> PAGE_SHIFT
;
786 pagecpy
= min_t(size_t, len
, PAGE_SIZE
- (offset
& ~PAGE_MASK
));
787 id
= bufb
->buf_rsb
.id
;
788 sb_bindex
= subbuffer_id_get_index(config
, id
);
789 rpages
= bufb
->array
[sb_bindex
];
790 CHAN_WARN_ON(chanb
, config
->mode
== RING_BUFFER_OVERWRITE
791 && subbuffer_id_is_noref(config
, id
));
792 memcpy(dest
, rpages
->p
[index
].virt
+ (offset
& ~PAGE_MASK
),
799 index
= (offset
& (chanb
->subbuf_size
- 1)) >> PAGE_SHIFT
;
801 * Underlying layer should never ask for reads across
804 CHAN_WARN_ON(chanb
, offset
>= chanb
->buf_size
);
808 EXPORT_SYMBOL_GPL(lib_ring_buffer_read
);
811 * __lib_ring_buffer_copy_to_user - read data from ring_buffer to userspace
812 * @bufb : buffer backend
813 * @offset : offset within the buffer
814 * @dest : destination userspace address
815 * @len : length to copy to destination
817 * Should be protected by get_subbuf/put_subbuf.
818 * access_ok() must have been performed on dest addresses prior to call this
820 * Returns -EFAULT on error, 0 if ok.
822 int __lib_ring_buffer_copy_to_user(struct lib_ring_buffer_backend
*bufb
,
823 size_t offset
, void __user
*dest
, size_t len
)
825 struct channel_backend
*chanb
= &bufb
->chan
->backend
;
826 const struct lib_ring_buffer_config
*config
= &chanb
->config
;
829 struct lib_ring_buffer_backend_pages
*rpages
;
830 unsigned long sb_bindex
, id
;
832 offset
&= chanb
->buf_size
- 1;
833 index
= (offset
& (chanb
->subbuf_size
- 1)) >> PAGE_SHIFT
;
837 pagecpy
= min_t(size_t, len
, PAGE_SIZE
- (offset
& ~PAGE_MASK
));
838 id
= bufb
->buf_rsb
.id
;
839 sb_bindex
= subbuffer_id_get_index(config
, id
);
840 rpages
= bufb
->array
[sb_bindex
];
841 CHAN_WARN_ON(chanb
, config
->mode
== RING_BUFFER_OVERWRITE
842 && subbuffer_id_is_noref(config
, id
));
843 if (__copy_to_user(dest
,
844 rpages
->p
[index
].virt
+ (offset
& ~PAGE_MASK
),
852 index
= (offset
& (chanb
->subbuf_size
- 1)) >> PAGE_SHIFT
;
854 * Underlying layer should never ask for reads across
857 CHAN_WARN_ON(chanb
, offset
>= chanb
->buf_size
);
861 EXPORT_SYMBOL_GPL(__lib_ring_buffer_copy_to_user
);
864 * lib_ring_buffer_read_cstr - read a C-style string from ring_buffer.
865 * @bufb : buffer backend
866 * @offset : offset within the buffer
867 * @dest : destination address
868 * @len : destination's length
870 * Return string's length, or -EINVAL on error.
871 * Should be protected by get_subbuf/put_subbuf.
872 * Destination length should be at least 1 to hold '\0'.
874 int lib_ring_buffer_read_cstr(struct lib_ring_buffer_backend
*bufb
, size_t offset
,
875 void *dest
, size_t len
)
877 struct channel_backend
*chanb
= &bufb
->chan
->backend
;
878 const struct lib_ring_buffer_config
*config
= &chanb
->config
;
880 ssize_t pagecpy
, pagelen
, strpagelen
, orig_offset
;
882 struct lib_ring_buffer_backend_pages
*rpages
;
883 unsigned long sb_bindex
, id
;
885 offset
&= chanb
->buf_size
- 1;
886 index
= (offset
& (chanb
->subbuf_size
- 1)) >> PAGE_SHIFT
;
887 orig_offset
= offset
;
891 id
= bufb
->buf_rsb
.id
;
892 sb_bindex
= subbuffer_id_get_index(config
, id
);
893 rpages
= bufb
->array
[sb_bindex
];
894 CHAN_WARN_ON(chanb
, config
->mode
== RING_BUFFER_OVERWRITE
895 && subbuffer_id_is_noref(config
, id
));
896 str
= (char *)rpages
->p
[index
].virt
+ (offset
& ~PAGE_MASK
);
897 pagelen
= PAGE_SIZE
- (offset
& ~PAGE_MASK
);
898 strpagelen
= strnlen(str
, pagelen
);
900 pagecpy
= min_t(size_t, len
, strpagelen
);
902 memcpy(dest
, str
, pagecpy
);
907 offset
+= strpagelen
;
908 index
= (offset
& (chanb
->subbuf_size
- 1)) >> PAGE_SHIFT
;
909 if (strpagelen
< pagelen
)
912 * Underlying layer should never ask for reads across
915 CHAN_WARN_ON(chanb
, offset
>= chanb
->buf_size
);
918 ((char *)dest
)[0] = 0;
919 return offset
- orig_offset
;
921 EXPORT_SYMBOL_GPL(lib_ring_buffer_read_cstr
);
924 * lib_ring_buffer_read_get_pfn - Get a page frame number to read from
925 * @bufb : buffer backend
926 * @offset : offset within the buffer
927 * @virt : pointer to page address (output)
929 * Should be protected by get_subbuf/put_subbuf.
930 * Returns the pointer to the page frame number unsigned long.
932 unsigned long *lib_ring_buffer_read_get_pfn(struct lib_ring_buffer_backend
*bufb
,
933 size_t offset
, void ***virt
)
936 struct lib_ring_buffer_backend_pages
*rpages
;
937 struct channel_backend
*chanb
= &bufb
->chan
->backend
;
938 const struct lib_ring_buffer_config
*config
= &chanb
->config
;
939 unsigned long sb_bindex
, id
;
941 offset
&= chanb
->buf_size
- 1;
942 index
= (offset
& (chanb
->subbuf_size
- 1)) >> PAGE_SHIFT
;
943 id
= bufb
->buf_rsb
.id
;
944 sb_bindex
= subbuffer_id_get_index(config
, id
);
945 rpages
= bufb
->array
[sb_bindex
];
946 CHAN_WARN_ON(chanb
, config
->mode
== RING_BUFFER_OVERWRITE
947 && subbuffer_id_is_noref(config
, id
));
948 *virt
= &rpages
->p
[index
].virt
;
949 return &rpages
->p
[index
].pfn
;
951 EXPORT_SYMBOL_GPL(lib_ring_buffer_read_get_pfn
);
954 * lib_ring_buffer_read_offset_address - get address of a buffer location
955 * @bufb : buffer backend
956 * @offset : offset within the buffer.
958 * Return the address where a given offset is located (for read).
959 * Should be used to get the current subbuffer header pointer. Given we know
960 * it's never on a page boundary, it's safe to read/write directly
961 * from/to this address, as long as the read/write is never bigger than a
964 void *lib_ring_buffer_read_offset_address(struct lib_ring_buffer_backend
*bufb
,
968 struct lib_ring_buffer_backend_pages
*rpages
;
969 struct channel_backend
*chanb
= &bufb
->chan
->backend
;
970 const struct lib_ring_buffer_config
*config
= &chanb
->config
;
971 unsigned long sb_bindex
, id
;
973 offset
&= chanb
->buf_size
- 1;
974 index
= (offset
& (chanb
->subbuf_size
- 1)) >> PAGE_SHIFT
;
975 id
= bufb
->buf_rsb
.id
;
976 sb_bindex
= subbuffer_id_get_index(config
, id
);
977 rpages
= bufb
->array
[sb_bindex
];
978 CHAN_WARN_ON(chanb
, config
->mode
== RING_BUFFER_OVERWRITE
979 && subbuffer_id_is_noref(config
, id
));
980 return rpages
->p
[index
].virt
+ (offset
& ~PAGE_MASK
);
982 EXPORT_SYMBOL_GPL(lib_ring_buffer_read_offset_address
);
985 * lib_ring_buffer_offset_address - get address of a location within the buffer
986 * @bufb : buffer backend
987 * @offset : offset within the buffer.
989 * Return the address where a given offset is located.
990 * Should be used to get the current subbuffer header pointer. Given we know
991 * it's always at the beginning of a page, it's safe to write directly to this
992 * address, as long as the write is never bigger than a page size.
994 void *lib_ring_buffer_offset_address(struct lib_ring_buffer_backend
*bufb
,
998 struct lib_ring_buffer_backend_pages
*rpages
;
999 struct channel_backend
*chanb
= &bufb
->chan
->backend
;
1000 const struct lib_ring_buffer_config
*config
= &chanb
->config
;
1001 unsigned long sb_bindex
, id
;
1003 offset
&= chanb
->buf_size
- 1;
1004 sbidx
= offset
>> chanb
->subbuf_size_order
;
1005 index
= (offset
& (chanb
->subbuf_size
- 1)) >> PAGE_SHIFT
;
1006 id
= bufb
->buf_wsb
[sbidx
].id
;
1007 sb_bindex
= subbuffer_id_get_index(config
, id
);
1008 rpages
= bufb
->array
[sb_bindex
];
1009 CHAN_WARN_ON(chanb
, config
->mode
== RING_BUFFER_OVERWRITE
1010 && subbuffer_id_is_noref(config
, id
));
1011 return rpages
->p
[index
].virt
+ (offset
& ~PAGE_MASK
);
1013 EXPORT_SYMBOL_GPL(lib_ring_buffer_offset_address
);