函数逻辑报告

Linux Kernel

v5.5.9

Brick Technologies Co., Ltd

Source Code:kernel\trace\trace_mmiotrace.c Create Date:2022-07-27 13:18:58
Last Modify:2020-03-12 14:18:49 Copyright©Brick
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函数名称：mmio_read

函数原型：static ssize_t mmio_read(struct trace_iterator *iter, 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 trace_iterator *iter
struct file *filp
char __user *ubuf
size_tcnt
loff_t *ppos
137  hiter等于private
138  s等于 The below is zeroed out in pipe_read
141  n等于count_overruns(iter)
142  如果n则
144  race_seq_printf - sequence printing of trace information*@s: trace sequence descriptor*@fmt: printf format string* The tracer may use either sequence operations or its own* copy to user routines
145  如果非overrun_detected则打印警告信息("mmiotrace has lost events\n")
147  overrun_detected = true
148  转到:print_out
151  如果非hiter则返回:0
154  mmio_print_pcidev(s, dev)
155  dev等于pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev)
157  如果非dev则
158  destroy_header_iter(hiter)
159  private = NULL
162  print_out :
163  ret等于race_seq_to_user - copy the squence buffer to user space*@s: trace sequence descriptor*@ubuf: The userspace memory location to copy to*@cnt: The amount to copy* Copies the sequence buffer into the userspace memory pointed to* by @ubuf
164  返回:如果ret恒等于负EBUSY则0否则ret