34     struct pipe_t *pipe_ptr = NULL;  in pipe_read()  local
37     pipe_ptr = (struct pipe_t *)file_ptr->private_data;  in pipe_read()
38     spin_lock(&pipe_ptr->data.lock);  in pipe_read()
39     while (pipe_ptr->data.valid_cnt == 0)  in pipe_read()
43         wait_queue_wakeup(&pipe_ptr->data.write_wait_queue, PROC_UNINTERRUPTIBLE);  in pipe_read()
44         wait_queue_sleep_on_unlock(&pipe_ptr->data.read_wait_queue, (void *)&pipe_ptr->data.lock);  in pipe_read()
45         spin_lock(&pipe_ptr->data.lock);  in pipe_read()
47     for (i = 0; i < pipe_ptr->data.valid_cnt; i++)  in pipe_read()
53         copy_to_user(buf + i, &pipe_ptr->buf[pipe_ptr->data.read_pos], sizeof(char));  in pipe_read()
54         pipe_ptr->data.read_pos = (pipe_ptr->data.read_pos + 1) % PIPE_BUFF_SIZE;  in pipe_read()
56     pipe_ptr->data.valid_cnt = pipe_ptr->data.valid_cnt - i;  in pipe_read()
57     spin_unlock(&pipe_ptr->data.lock);  in pipe_read()
58     wait_queue_wakeup(&pipe_ptr->data.write_wait_queue, PROC_UNINTERRUPTIBLE);  in pipe_read()
67     struct pipe_t *pipe_ptr = NULL;  in pipe_write()  local
70     pipe_ptr = (struct pipe_t *)file_ptr->private_data;  in pipe_write()
71     spin_lock(&pipe_ptr->data.lock);  in pipe_write()
72     while (pipe_ptr->data.valid_cnt + count >= PIPE_BUFF_SIZE)  in pipe_write()
76         wait_queue_wakeup(&pipe_ptr->data.read_wait_queue, PROC_UNINTERRUPTIBLE);  in pipe_write()
77         wait_queue_sleep_on_unlock(&pipe_ptr->data.write_wait_queue, (void *)&pipe_ptr->data.lock);  in pipe_write()
78         spin_lock(&pipe_ptr->data.lock);  in pipe_write()
80     for (i = pipe_ptr->data.valid_cnt; i < PIPE_BUFF_SIZE; i++)  in pipe_write()
82         if (i - pipe_ptr->data.valid_cnt == count)  in pipe_write()
86         copy_from_user(&pipe_ptr->buf[pipe_ptr->data.write_pos], buf + i, sizeof(char));  in pipe_write()
87         pipe_ptr->data.write_pos = (pipe_ptr->data.write_pos + 1) % PIPE_BUFF_SIZE;  in pipe_write()
89     pipe_ptr->data.valid_cnt += count;  in pipe_write()
90     spin_unlock(&pipe_ptr->data.lock);  in pipe_write()
91     wait_queue_wakeup(&pipe_ptr->data.read_wait_queue, PROC_UNINTERRUPTIBLE);  in pipe_write()
114     struct pipe_t *pipe_ptr = NULL;  in pipe_alloc()  local
116     pipe_ptr = (struct pipe_t *)kzalloc(sizeof(struct pipe_t), 0);  in pipe_alloc()
117     spin_init(&pipe_ptr->data.lock);  in pipe_alloc()
118     pipe_ptr->data.read_pos = 0;  in pipe_alloc()
119     pipe_ptr->data.write_pos = 0;  in pipe_alloc()
120     pipe_ptr->data.valid_cnt = 0;  in pipe_alloc()
121     memset(pipe_ptr->buf, 0, PIPE_BUFF_SIZE);  in pipe_alloc()
122     wait_queue_init(&pipe_ptr->data.read_wait_queue, NULL);  in pipe_alloc()
123     wait_queue_init(&pipe_ptr->data.write_wait_queue, NULL);  in pipe_alloc()
125     return pipe_ptr;  in pipe_alloc()
138     struct pipe_t *pipe_ptr = NULL;  in sys_pipe()  local
145     pipe_ptr = pipe_alloc();  in sys_pipe()
152         kfree(pipe_ptr);  in sys_pipe()
161         kfree(pipe_ptr);  in sys_pipe()
167     read_file->private_data = (void *)pipe_ptr;  in sys_pipe()
170     write_file->private_data = (void *)pipe_ptr;  in sys_pipe()