linux/kernel/trace/pid_list.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2021 VMware Inc, Steven Rostedt <[email protected]>
 */
#include <linux/spinlock.h>
#include <linux/irq_work.h>
#include <linux/slab.h>
#include "trace.h"

/* See pid_list.h for details */

static inline union lower_chunk *get_lower_chunk(struct trace_pid_list *pid_list)
{ … }

static inline union upper_chunk *get_upper_chunk(struct trace_pid_list *pid_list)
{ … }

static inline void put_lower_chunk(struct trace_pid_list *pid_list,
				   union lower_chunk *chunk)
{ … }

static inline void put_upper_chunk(struct trace_pid_list *pid_list,
				   union upper_chunk *chunk)
{ … }

static inline bool upper_empty(union upper_chunk *chunk)
{ … }

static inline int pid_split(unsigned int pid, unsigned int *upper1,
			     unsigned int *upper2, unsigned int *lower)
{ … }

static inline unsigned int pid_join(unsigned int upper1,
				    unsigned int upper2, unsigned int lower)
{ … }

/**
 * trace_pid_list_is_set - test if the pid is set in the list
 * @pid_list: The pid list to test
 * @pid: The pid to see if set in the list.
 *
 * Tests if @pid is set in the @pid_list. This is usually called
 * from the scheduler when a task is scheduled. Its pid is checked
 * if it should be traced or not.
 *
 * Return true if the pid is in the list, false otherwise.
 */
bool trace_pid_list_is_set(struct trace_pid_list *pid_list, unsigned int pid)
{ … }

/**
 * trace_pid_list_set - add a pid to the list
 * @pid_list: The pid list to add the @pid to.
 * @pid: The pid to add.
 *
 * Adds @pid to @pid_list. This is usually done explicitly by a user
 * adding a task to be traced, or indirectly by the fork function
 * when children should be traced and a task's pid is in the list.
 *
 * Return 0 on success, negative otherwise.
 */
int trace_pid_list_set(struct trace_pid_list *pid_list, unsigned int pid)
{ … }

/**
 * trace_pid_list_clear - remove a pid from the list
 * @pid_list: The pid list to remove the @pid from.
 * @pid: The pid to remove.
 *
 * Removes @pid from @pid_list. This is usually done explicitly by a user
 * removing tasks from tracing, or indirectly by the exit function
 * when a task that is set to be traced exits.
 *
 * Return 0 on success, negative otherwise.
 */
int trace_pid_list_clear(struct trace_pid_list *pid_list, unsigned int pid)
{ … }

/**
 * trace_pid_list_next - return the next pid in the list
 * @pid_list: The pid list to examine.
 * @pid: The pid to start from
 * @next: The pointer to place the pid that is set starting from @pid.
 *
 * Looks for the next consecutive pid that is in @pid_list starting
 * at the pid specified by @pid. If one is set (including @pid), then
 * that pid is placed into @next.
 *
 * Return 0 when a pid is found, -1 if there are no more pids included.
 */
int trace_pid_list_next(struct trace_pid_list *pid_list, unsigned int pid,
			unsigned int *next)
{ … }

/**
 * trace_pid_list_first - return the first pid in the list
 * @pid_list: The pid list to examine.
 * @pid: The pointer to place the pid first found pid that is set.
 *
 * Looks for the first pid that is set in @pid_list, and places it
 * into @pid if found.
 *
 * Return 0 when a pid is found, -1 if there are no pids set.
 */
int trace_pid_list_first(struct trace_pid_list *pid_list, unsigned int *pid)
{ … }

static void pid_list_refill_irq(struct irq_work *iwork)
{ … }

/**
 * trace_pid_list_alloc - create a new pid_list
 *
 * Allocates a new pid_list to store pids into.
 *
 * Returns the pid_list on success, NULL otherwise.
 */
struct trace_pid_list *trace_pid_list_alloc(void)
{ … }

/**
 * trace_pid_list_free - Frees an allocated pid_list.
 * @pid_list: The pid list to free.
 *
 * Frees the memory for a pid_list that was allocated.
 */
void trace_pid_list_free(struct trace_pid_list *pid_list)
{ … }