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Commit ee000b7f authored by Lai Jiangshan's avatar Lai Jiangshan Committed by Ingo Molnar
Browse files

tracing: use union for multi-usages field 



Impact: cleanup

struct dyn_ftrace::ip has different usages in his lifecycle,
we use union for it. And also for struct dyn_ftrace::flags.

Signed-off-by: default avatarLai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <49C871BE.3080405@cn.fujitsu.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent cc59c9e8

include/linux/ftrace.h

+9 −3
Original line number Diff line number Diff line
@@ -145,8 +145,14 @@ enum { 
};



struct dyn_ftrace {

	union {

		unsigned long		ip; /* address of mcount call-site */

		struct dyn_ftrace	*freelist;

	};

	union {

		unsigned long		flags;

		struct dyn_ftrace	*newlist;

	};

	struct dyn_arch_ftrace		arch;

};

kernel/trace/ftrace.c

+4 −4
Original line number Diff line number Diff line
@@ -341,7 +341,7 @@ static inline int record_frozen(struct dyn_ftrace *rec) 


static void ftrace_free_rec(struct dyn_ftrace *rec)

{

	rec->ip = (unsigned long)ftrace_free_records;

	rec->freelist = ftrace_free_records;

	ftrace_free_records = rec;

	rec->flags |= FTRACE_FL_FREE;

}
@@ -379,7 +379,7 @@ static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip) 
			return NULL;

		}



		ftrace_free_records = (void *)rec->ip;

		ftrace_free_records = rec->freelist;

		memset(rec, 0, sizeof(*rec));

		return rec;

	}
@@ -411,7 +411,7 @@ ftrace_record_ip(unsigned long ip) 
		return NULL;



	rec->ip = ip;

	rec->flags = (unsigned long)ftrace_new_addrs;

	rec->newlist = ftrace_new_addrs;

	ftrace_new_addrs = rec;



	return rec;
@@ -731,7 +731,7 @@ static int ftrace_update_code(struct module *mod) 
			return -1;



		p = ftrace_new_addrs;

		ftrace_new_addrs = (struct dyn_ftrace *)p->flags;

		ftrace_new_addrs = p->newlist;

		p->flags = 0L;



		/* convert record (i.e, patch mcount-call with NOP) */