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Commit 64fbcd16 authored by Xiao Guangrong's avatar Xiao Guangrong Committed by Frederic Weisbecker
Browse files

tracing/function: Simplify __ftrace_replace_code() 



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: default avatarXiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Reviewed-by: default avatarLi Zefan <lizf@cn.fujitsu.com>
Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
parent da706d8b

kernel/trace/ftrace.c

+18 −54
Original line number Diff line number Diff line
@@ -1017,70 +1017,34 @@ 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 && !(rec->flags & FTRACE_FL_NOTRACE)) {

		if (!ftrace_filtered || (rec->flags & FTRACE_FL_FILTER))

			flag = FTRACE_FL_ENABLED;

	}



		if (enable) {

			/* if record is enabled, do nothing */

			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;



		} else {



			/* if record is not enabled, do nothing */

			if (!(rec->flags & FTRACE_FL_ENABLED))

				return 0;



			rec->flags &= ~FTRACE_FL_ENABLED;

		}

		return ftrace_make_call(rec, ftrace_addr);

	}



	if (rec->flags & FTRACE_FL_ENABLED)

		return ftrace_make_call(rec, ftrace_addr);

	else

	rec->flags &= ~FTRACE_FL_ENABLED;

	return ftrace_make_nop(NULL, rec, ftrace_addr);

}