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tracing/function: Simplify __ftrace_replace_code()

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Rewrite the __ftrace_replace_code() function, simplify it, but don't
change the code's logic.

First, we get the state we want to set, if the record has the same
state, then do nothing, otherwise enable/disable it.

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
This commit is contained in:
Xiao Guangrong 2009-07-15 12:32:15 +08:00 committed by Frederic Weisbecker
parent da706d8bc8
commit 64fbcd1628
1 changed files with 19 additions and 55 deletions
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74
kernel/trace/ftrace.c
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@ -1017,71 +1017,35 @@ static int
__ftrace_replace_code(struct dyn_ftrace *rec, int enable)
{
unsigned long ftrace_addr;
unsigned long ip, fl;
unsigned long flag = 0UL;
ftrace_addr = (unsigned long)FTRACE_ADDR;
ip = rec->ip;
/*
* If this record is not to be traced and
* it is not enabled then do nothing.
* If this record is not to be traced or we want to disable it,
* then disable it.
*
* If this record is not to be traced and
* it is enabled then disable it.
* If we want to enable it and filtering is off, then enable it.
*
* If we want to enable it and filtering is on, enable it only if
* it's filtered
*/
if (rec->flags & FTRACE_FL_NOTRACE) {
if (rec->flags & FTRACE_FL_ENABLED)
rec->flags &= ~FTRACE_FL_ENABLED;
else
return 0;
} else if (ftrace_filtered && enable) {
/*
* Filtering is on:
*/
fl = rec->flags & (FTRACE_FL_FILTER | FTRACE_FL_ENABLED);
/* Record is filtered and enabled, do nothing */
if (fl == (FTRACE_FL_FILTER | FTRACE_FL_ENABLED))
return 0;
/* Record is not filtered or enabled, do nothing */
if (!fl)
return 0;
/* Record is not filtered but enabled, disable it */
if (fl == FTRACE_FL_ENABLED)
rec->flags &= ~FTRACE_FL_ENABLED;
else
/* Otherwise record is filtered but not enabled, enable it */
rec->flags |= FTRACE_FL_ENABLED;
} else {
/* Disable or not filtered */
if (enable) {
/* if record is enabled, do nothing */
if (rec->flags & FTRACE_FL_ENABLED)
return 0;
rec->flags |= FTRACE_FL_ENABLED;
} else {
/* if record is not enabled, do nothing */
if (!(rec->flags & FTRACE_FL_ENABLED))
return 0;
rec->flags &= ~FTRACE_FL_ENABLED;
}
if (enable && !(rec->flags & FTRACE_FL_NOTRACE)) {
if (!ftrace_filtered || (rec->flags & FTRACE_FL_FILTER))
flag = FTRACE_FL_ENABLED;
}
if (rec->flags & FTRACE_FL_ENABLED)
/* If the state of this record hasn't changed, then do nothing */
if ((rec->flags & FTRACE_FL_ENABLED) == flag)
return 0;
if (flag) {
rec->flags |= FTRACE_FL_ENABLED;
return ftrace_make_call(rec, ftrace_addr);
else
return ftrace_make_nop(NULL, rec, ftrace_addr);
}
rec->flags &= ~FTRACE_FL_ENABLED;
return ftrace_make_nop(NULL, rec, ftrace_addr);
}
static void ftrace_replace_code(int enable)