函数逻辑报告

Linux Kernel

v5.5.9

Brick Technologies Co., Ltd

Source Code:kernel\trace\trace.c Create Date:2022-07-27 13:08:18
Last Modify:2020-03-12 14:18:49 Copyright©Brick
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函数名称：tracing_total_entries_read

函数原型：static ssize_t tracing_total_entries_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)

返回类型：ssize_t

参数：

类型参数名称
struct file *filp
char __user *ubuf
size_tcnt
loff_t *ppos
6418  tr等于 needed for tty driver, and maybe others
6421  size等于0, expanded_size等于0
6423  mutex_lock( & race_types_lock is used to protect the trace_types list.)
6424  for_each_tracing_cpu(cpu)
6425  size += ({
6425  ({
6425  循环
6425  const void * __vpp_verify = NULL
6425  当0循环
6425  data
6425  })
6425  })->entries >> 10
6426  如果非On boot up, the ring buffer is set to the minimum size, so that* we do not waste memory on systems that are not using tracing.则expanded_size加等于trace_buf_size右移10位
6429  如果On boot up, the ring buffer is set to the minimum size, so that* we do not waste memory on systems that are not using tracing.则r等于输出格式化串
6431  否则r等于输出格式化串
6433  mutex_unlock - release the mutex*@lock: the mutex to be released* Unlock a mutex that has been locked by this task previously.* This function must not be used in interrupt context. Unlocking* of a not locked mutex is not allowed.
6435  返回:simple_read_from_buffer(ubuf, cnt, ppos, buf, r)