213 lines
7.1 KiB
C
213 lines
7.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_RING_BUFFER_H
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#define _LINUX_RING_BUFFER_H
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#include <linux/mm.h>
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#include <linux/seq_file.h>
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#include <linux/poll.h>
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struct ring_buffer;
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struct ring_buffer_iter;
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/*
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* Don't refer to this struct directly, use functions below.
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*/
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struct ring_buffer_event {
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u32 type_len:5, time_delta:27;
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u32 array[];
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};
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/**
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* enum ring_buffer_type - internal ring buffer types
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*
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* @RINGBUF_TYPE_PADDING: Left over page padding or discarded event
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* If time_delta is 0:
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* array is ignored
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* size is variable depending on how much
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* padding is needed
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* If time_delta is non zero:
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* array[0] holds the actual length
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* size = 4 + length (bytes)
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*
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* @RINGBUF_TYPE_TIME_EXTEND: Extend the time delta
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* array[0] = time delta (28 .. 59)
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* size = 8 bytes
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*
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* @RINGBUF_TYPE_TIME_STAMP: Absolute timestamp
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* Same format as TIME_EXTEND except that the
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* value is an absolute timestamp, not a delta
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* event.time_delta contains bottom 27 bits
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* array[0] = top (28 .. 59) bits
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* size = 8 bytes
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*
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* <= @RINGBUF_TYPE_DATA_TYPE_LEN_MAX:
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* Data record
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* If type_len is zero:
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* array[0] holds the actual length
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* array[1..(length+3)/4] holds data
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* size = 4 + length (bytes)
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* else
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* length = type_len << 2
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* array[0..(length+3)/4-1] holds data
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* size = 4 + length (bytes)
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*/
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enum ring_buffer_type {
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RINGBUF_TYPE_DATA_TYPE_LEN_MAX = 28,
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RINGBUF_TYPE_PADDING,
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RINGBUF_TYPE_TIME_EXTEND,
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RINGBUF_TYPE_TIME_STAMP,
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};
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unsigned ring_buffer_event_length(struct ring_buffer_event *event);
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void *ring_buffer_event_data(struct ring_buffer_event *event);
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u64 ring_buffer_event_time_stamp(struct ring_buffer_event *event);
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/*
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* ring_buffer_discard_commit will remove an event that has not
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* been committed yet. If this is used, then ring_buffer_unlock_commit
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* must not be called on the discarded event. This function
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* will try to remove the event from the ring buffer completely
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* if another event has not been written after it.
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*
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* Example use:
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*
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* if (some_condition)
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* ring_buffer_discard_commit(buffer, event);
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* else
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* ring_buffer_unlock_commit(buffer, event);
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*/
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void ring_buffer_discard_commit(struct ring_buffer *buffer,
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struct ring_buffer_event *event);
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/*
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* size is in bytes for each per CPU buffer.
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*/
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struct ring_buffer *
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__ring_buffer_alloc(unsigned long size, unsigned flags, struct lock_class_key *key);
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/*
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* Because the ring buffer is generic, if other users of the ring buffer get
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* traced by ftrace, it can produce lockdep warnings. We need to keep each
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* ring buffer's lock class separate.
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*/
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#define ring_buffer_alloc(size, flags) \
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({ \
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static struct lock_class_key __key; \
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__ring_buffer_alloc((size), (flags), &__key); \
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})
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int ring_buffer_wait(struct ring_buffer *buffer, int cpu, bool full);
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__poll_t ring_buffer_poll_wait(struct ring_buffer *buffer, int cpu,
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struct file *filp, poll_table *poll_table);
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#define RING_BUFFER_ALL_CPUS -1
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void ring_buffer_free(struct ring_buffer *buffer);
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int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size, int cpu);
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void ring_buffer_change_overwrite(struct ring_buffer *buffer, int val);
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struct ring_buffer_event *ring_buffer_lock_reserve(struct ring_buffer *buffer,
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unsigned long length);
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int ring_buffer_unlock_commit(struct ring_buffer *buffer,
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struct ring_buffer_event *event);
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int ring_buffer_write(struct ring_buffer *buffer,
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unsigned long length, void *data);
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void ring_buffer_nest_start(struct ring_buffer *buffer);
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void ring_buffer_nest_end(struct ring_buffer *buffer);
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struct ring_buffer_event *
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ring_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts,
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unsigned long *lost_events);
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struct ring_buffer_event *
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ring_buffer_consume(struct ring_buffer *buffer, int cpu, u64 *ts,
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unsigned long *lost_events);
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struct ring_buffer_iter *
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ring_buffer_read_prepare(struct ring_buffer *buffer, int cpu);
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void ring_buffer_read_prepare_sync(void);
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void ring_buffer_read_start(struct ring_buffer_iter *iter);
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void ring_buffer_read_finish(struct ring_buffer_iter *iter);
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struct ring_buffer_event *
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ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts);
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struct ring_buffer_event *
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ring_buffer_read(struct ring_buffer_iter *iter, u64 *ts);
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void ring_buffer_iter_reset(struct ring_buffer_iter *iter);
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int ring_buffer_iter_empty(struct ring_buffer_iter *iter);
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unsigned long ring_buffer_size(struct ring_buffer *buffer, int cpu);
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void ring_buffer_reset_cpu(struct ring_buffer *buffer, int cpu);
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void ring_buffer_reset(struct ring_buffer *buffer);
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#ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
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int ring_buffer_swap_cpu(struct ring_buffer *buffer_a,
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struct ring_buffer *buffer_b, int cpu);
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#else
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static inline int
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ring_buffer_swap_cpu(struct ring_buffer *buffer_a,
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struct ring_buffer *buffer_b, int cpu)
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{
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return -ENODEV;
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}
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#endif
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bool ring_buffer_empty(struct ring_buffer *buffer);
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bool ring_buffer_empty_cpu(struct ring_buffer *buffer, int cpu);
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void ring_buffer_record_disable(struct ring_buffer *buffer);
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void ring_buffer_record_enable(struct ring_buffer *buffer);
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void ring_buffer_record_off(struct ring_buffer *buffer);
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void ring_buffer_record_on(struct ring_buffer *buffer);
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int ring_buffer_record_is_on(struct ring_buffer *buffer);
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void ring_buffer_record_disable_cpu(struct ring_buffer *buffer, int cpu);
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void ring_buffer_record_enable_cpu(struct ring_buffer *buffer, int cpu);
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u64 ring_buffer_oldest_event_ts(struct ring_buffer *buffer, int cpu);
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unsigned long ring_buffer_bytes_cpu(struct ring_buffer *buffer, int cpu);
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unsigned long ring_buffer_entries(struct ring_buffer *buffer);
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unsigned long ring_buffer_overruns(struct ring_buffer *buffer);
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unsigned long ring_buffer_entries_cpu(struct ring_buffer *buffer, int cpu);
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unsigned long ring_buffer_overrun_cpu(struct ring_buffer *buffer, int cpu);
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unsigned long ring_buffer_commit_overrun_cpu(struct ring_buffer *buffer, int cpu);
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unsigned long ring_buffer_dropped_events_cpu(struct ring_buffer *buffer, int cpu);
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unsigned long ring_buffer_read_events_cpu(struct ring_buffer *buffer, int cpu);
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u64 ring_buffer_time_stamp(struct ring_buffer *buffer, int cpu);
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void ring_buffer_normalize_time_stamp(struct ring_buffer *buffer,
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int cpu, u64 *ts);
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void ring_buffer_set_clock(struct ring_buffer *buffer,
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u64 (*clock)(void));
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void ring_buffer_set_time_stamp_abs(struct ring_buffer *buffer, bool abs);
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bool ring_buffer_time_stamp_abs(struct ring_buffer *buffer);
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size_t ring_buffer_page_len(void *page);
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void *ring_buffer_alloc_read_page(struct ring_buffer *buffer, int cpu);
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void ring_buffer_free_read_page(struct ring_buffer *buffer, int cpu, void *data);
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int ring_buffer_read_page(struct ring_buffer *buffer, void **data_page,
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size_t len, int cpu, int full);
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struct trace_seq;
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int ring_buffer_print_entry_header(struct trace_seq *s);
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int ring_buffer_print_page_header(struct trace_seq *s);
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enum ring_buffer_flags {
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RB_FL_OVERWRITE = 1 << 0,
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};
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#ifdef CONFIG_RING_BUFFER
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int trace_rb_cpu_prepare(unsigned int cpu, struct hlist_node *node);
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#else
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#define trace_rb_cpu_prepare NULL
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#endif
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#endif /* _LINUX_RING_BUFFER_H */
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