Orange Pi5 kernel

// SPDX-License-Identifier: GPL-2.0
#include "comm.h"
#include <errno.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <linux/refcount.h>
#include <linux/rbtree.h>
#include <linux/zalloc.h>
#include "rwsem.h"
 
struct comm_str {
<------>char *str;
<------>struct rb_node rb_node;
<------>refcount_t refcnt;
};
 
/* Should perhaps be moved to struct machine */
static struct rb_root comm_str_root;
static struct rw_semaphore comm_str_lock = {.lock = PTHREAD_RWLOCK_INITIALIZER,};
 
static struct comm_str *comm_str__get(struct comm_str *cs)
{
<------>if (cs && refcount_inc_not_zero(&cs->refcnt))
<------><------>return cs;
 
<------>return NULL;
}
 
static void comm_str__put(struct comm_str *cs)
{
<------>if (cs && refcount_dec_and_test(&cs->refcnt)) {
<------><------>down_write(&comm_str_lock);
<------><------>rb_erase(&cs->rb_node, &comm_str_root);
<------><------>up_write(&comm_str_lock);
<------><------>zfree(&cs->str);
<------><------>free(cs);
<------>}
}
 
static struct comm_str *comm_str__alloc(const char *str)
{
<------>struct comm_str *cs;
 
<------>cs = zalloc(sizeof(*cs));
<------>if (!cs)
<------><------>return NULL;
 
<------>cs->str = strdup(str);
<------>if (!cs->str) {
<------><------>free(cs);
<------><------>return NULL;
<------>}
 
<------>refcount_set(&cs->refcnt, 1);
 
<------>return cs;
}
 
static
struct comm_str *__comm_str__findnew(const char *str, struct rb_root *root)
{
<------>struct rb_node **p = &root->rb_node;
<------>struct rb_node *parent = NULL;
<------>struct comm_str *iter, *new;
<------>int cmp;
 
<------>while (*p != NULL) {
<------><------>parent = *p;
<------><------>iter = rb_entry(parent, struct comm_str, rb_node);
 
<------><------>/*
<------><------> * If we race with comm_str__put, iter->refcnt is 0
<------><------> * and it will be removed within comm_str__put call
<------><------> * shortly, ignore it in this search.
<------><------> */
<------><------>cmp = strcmp(str, iter->str);
<------><------>if (!cmp && comm_str__get(iter))
<------><------><------>return iter;
 
<------><------>if (cmp < 0)
<------><------><------>p = &(*p)->rb_left;
<------><------>else
<------><------><------>p = &(*p)->rb_right;
<------>}
 
<------>new = comm_str__alloc(str);
<------>if (!new)
<------><------>return NULL;
 
<------>rb_link_node(&new->rb_node, parent, p);
<------>rb_insert_color(&new->rb_node, root);
 
<------>return new;
}
 
static struct comm_str *comm_str__findnew(const char *str, struct rb_root *root)
{
<------>struct comm_str *cs;
 
<------>down_write(&comm_str_lock);
<------>cs = __comm_str__findnew(str, root);
<------>up_write(&comm_str_lock);
 
<------>return cs;
}
 
struct comm *comm__new(const char *str, u64 timestamp, bool exec)
{
<------>struct comm *comm = zalloc(sizeof(*comm));
 
<------>if (!comm)
<------><------>return NULL;
 
<------>comm->start = timestamp;
<------>comm->exec = exec;
 
<------>comm->comm_str = comm_str__findnew(str, &comm_str_root);
<------>if (!comm->comm_str) {
<------><------>free(comm);
<------><------>return NULL;
<------>}
 
<------>return comm;
}
 
int comm__override(struct comm *comm, const char *str, u64 timestamp, bool exec)
{
<------>struct comm_str *new, *old = comm->comm_str;
 
<------>new = comm_str__findnew(str, &comm_str_root);
<------>if (!new)
<------><------>return -ENOMEM;
 
<------>comm_str__put(old);
<------>comm->comm_str = new;
<------>comm->start = timestamp;
<------>if (exec)
<------><------>comm->exec = true;
 
<------>return 0;
}
 
void comm__free(struct comm *comm)
{
<------>comm_str__put(comm->comm_str);
<------>free(comm);
}
 
const char *comm__str(const struct comm *comm)
{
<------>return comm->comm_str->str;
}