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| author | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2017-05-03 11:41:44 -0400 |
|---|---|---|
| committer | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2017-05-03 22:15:13 -0400 |
| commit | 77c0eddeeeee14bf0fb0c0bb97e782981bbcf084 (patch) | |
| tree | 0e5c2135c8d4364668ede155ee0b7522537f6c24 /kernel/trace | |
| parent | 31805c90521ea75dfa3d016fc94f581da6a40fee (diff) | |
| download | linux-77c0eddeeeee14bf0fb0c0bb97e782981bbcf084.tar.gz linux-77c0eddeeeee14bf0fb0c0bb97e782981bbcf084.tar.bz2 linux-77c0eddeeeee14bf0fb0c0bb97e782981bbcf084.zip | |
ftrace: Simplify ftrace_match_record() even more
Dan Carpenter sent a patch to remove a check in ftrace_match_record()
because the logic of the code made the check redundant. I looked deeper into
the code, and made the following logic table, with the three variables and
the result of the original code.
modname mod_matches exclude_mod result
------- ----------- ----------- ------
0 0 0 return 0
0 0 1 func_match
0 1 * < cannot exist >
1 0 0 return 0
1 0 1 func_match
1 1 0 func_match
1 1 1 return 0
Notice that when mod_matches == exclude mod, the result is always to
return 0, and when mod_matches != exclude_mod, then the result is to test
the function. This means we only need test if mod_matches is equal to
exclude_mod.
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace')
| -rw-r--r-- | kernel/trace/ftrace.c | 20 |
1 files changed, 9 insertions, 11 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 84286d347cd8..39dca4e86a94 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -3631,22 +3631,20 @@ ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g, /* blank module name to match all modules */ if (!mod_g->len) { /* blank module globbing: modname xor exclude_mod */ - if ((!exclude_mod) != (!modname)) + if (!exclude_mod != !modname) goto func_match; return 0; } - /* not matching the module */ - if (!modname || !mod_matches) { - if (exclude_mod) - goto func_match; - else - return 0; - } - - if (exclude_mod) + /* + * exclude_mod is set to trace everything but the given + * module. If it is set and the module matches, then + * return 0. If it is not set, and the module doesn't match + * also return 0. Otherwise, check the function to see if + * that matches. + */ + if (!mod_matches == !exclude_mod) return 0; - func_match: /* blank search means to match all funcs in the mod */ if (!func_g->len) |