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 13:08:13
Last Modify:2020-03-12 14:18:49 Copyright©Brick
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函数名称：tracing_entries_read

函数原型：static ssize_t tracing_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
6342  inode等于file_inode(filp)
6343  tr等于s or device private pointer
6344  cpu等于Should be used after trace_array_get(), trace_types_lock* ensures that i_cdev was already initialized.
6346  r等于0
6349  mutex_lock( & race_types_lock is used to protect the trace_types list.)
6351  如果cpu恒等于RING_BUFFER_ALL_CPUS则
6355  size等于0
6356  buf_size_same等于1
6358  for_each_tracing_cpu(cpu)
6360  如果size恒等于0则size = ({
6361  ({
6361  循环
6361  const void * __vpp_verify = NULL
6361  当0循环
6361  data
6361  })
6361  })->entries
6362  if (size != ({
6362  ({
6362  循环
6362  const void * __vpp_verify = NULL
6362  当0循环
6362  data
6362  })
6362  })->entries)
6363  buf_size_same等于0
6364  退出
6368  如果buf_size_same则
6369  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r等于输出格式化串
6373  否则r等于输出格式化串
6375  否则r等于输出格式化串
6377  否则r等于输出格式化串
6380  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.
6382  ret等于simple_read_from_buffer(ubuf, cnt, ppos, buf, r)
6383  返回:ret