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authorSteven Rostedt <srostedt@redhat.com>2008-11-15 16:31:41 -0500
committerIngo Molnar <mingo@elte.hu>2008-11-16 07:37:17 +0100
commit982c350b9ec4b3564d67f3627a274ae61bbc7e95 (patch)
treec7ccd83698552997bcfe58ab7f61b8761d37957e /kernel
parent20e5227e9f55ae1969934821ccbf581563785bbe (diff)
ftrace: fix dyn ftrace filter
Impact: correct implementation of dyn ftrace filter The old decisions made by the filter algorithm was complex and incorrect. This lead to inconsistent enabling or disabling of functions when the filter was used. This patch simplifies that code and in doing so, corrects the usage of the filters. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/ftrace.c83
1 files changed, 36 insertions, 47 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index cc4219135dc..b9f2e22faf2 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -394,72 +394,62 @@ __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
ip = rec->ip;
- if (ftrace_filtered && enable) {
+ /*
+ * If this record is not to be traced and
+ * it is not enabled then do nothing.
+ *
+ * If this record is not to be traced and
+ * it is enabled then disabled it.
+ *
+ */
+ 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) {
/*
- * If filtering is on:
- *
- * If this record is set to be filtered and
- * is enabled then do nothing.
- *
- * If this record is set to be filtered and
- * it is not enabled, enable it.
- *
- * If this record is not set to be filtered
- * and it is not enabled do nothing.
- *
- * If this record is set not to trace then
- * do nothing.
- *
- * If this record is set not to trace and
- * it is enabled then disable it.
- *
- * If this record is not set to be filtered and
- * it is enabled, disable it.
+ * Filtering is on:
*/
- fl = rec->flags & (FTRACE_FL_FILTER | FTRACE_FL_NOTRACE |
- FTRACE_FL_ENABLED);
+ fl = rec->flags & (FTRACE_FL_FILTER | FTRACE_FL_ENABLED);
- if ((fl == (FTRACE_FL_FILTER | FTRACE_FL_ENABLED)) ||
- (fl == (FTRACE_FL_FILTER | FTRACE_FL_NOTRACE)) ||
- !fl || (fl == FTRACE_FL_NOTRACE))
+ /* Record is filtered and enabled, do nothing */
+ if (fl == (FTRACE_FL_FILTER | FTRACE_FL_ENABLED))
return 0;
- /*
- * If it is enabled disable it,
- * otherwise enable it!
- */
- if (fl & FTRACE_FL_ENABLED) {
- enable = 0;
+ /* Record is not filtered and is not 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 {
- enable = 1;
+ else
+ /* Otherwise record is filtered but not enabled, enable it */
rec->flags |= FTRACE_FL_ENABLED;
- }
} else {
+ /* Disable or not filtered */
if (enable) {
- /*
- * If this record is set not to trace and is
- * not enabled, do nothing.
- */
- fl = rec->flags & (FTRACE_FL_NOTRACE | FTRACE_FL_ENABLED);
- if (fl == FTRACE_FL_NOTRACE)
- return 0;
- }
-
- 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)
+ if (rec->flags & FTRACE_FL_ENABLED)
return ftrace_make_call(rec, FTRACE_ADDR);
else
return ftrace_make_nop(NULL, rec, FTRACE_ADDR);
@@ -554,8 +544,7 @@ static void ftrace_startup(void)
mutex_lock(&ftrace_start_lock);
ftrace_start_up++;
- if (ftrace_start_up == 1)
- command |= FTRACE_ENABLE_CALLS;
+ command |= FTRACE_ENABLE_CALLS;
if (saved_ftrace_func != ftrace_trace_function) {
saved_ftrace_func = ftrace_trace_function;