tracing: Simplify trace_option_write()

- remove duplicate code inside trace_options_write()
- extract duplicate code in trace_options_write() and set_tracer_option()

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <4B1DC532.9010802@cn.fujitsu.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

1 files changed, 31 insertions, 54 deletions

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 898409d60422..05076008f371 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2343,38 +2343,39 @@ static int tracing_trace_options_show(struct seq_file *m, void *v)
         return 0;
 }
 
+static int __set_tracer_option(struct tracer *trace,
+                               struct tracer_flags *tracer_flags,
+                               struct tracer_opt *opts, int neg)
+{
+        int ret;
+
+        ret = trace->set_flag(tracer_flags->val, opts->bit, !neg);
+        if (ret)
+                return ret;
+
+        if (neg)
+                tracer_flags->val &= ~opts->bit;
+        else
+                tracer_flags->val |= opts->bit;
+        return 0;
+}
+
 /* Try to assign a tracer specific option */
 static int set_tracer_option(struct tracer *trace, char *cmp, int neg)
 {
         struct tracer_flags *tracer_flags = trace->flags;
         struct tracer_opt *opts = NULL;
-        int ret = 0, i = 0;
-        int len;
+        int i;
 
         for (i = 0; tracer_flags->opts[i].name; i++) {
                 opts = &tracer_flags->opts[i];
-                len = strlen(opts->name);
 
-                if (strncmp(cmp, opts->name, len) == 0) {
-                        ret = trace->set_flag(tracer_flags->val,
-                                opts->bit, !neg);
-                        break;
-                }
+                if (strcmp(cmp, opts->name) == 0)
+                        return __set_tracer_option(trace, trace->flags,
+                                                   opts, neg);
         }
-        /* Not found */
-        if (!tracer_flags->opts[i].name)
-                return -EINVAL;
 
-        /* Refused to handle */
-        if (ret)
-                return ret;
-
-        if (neg)
-                tracer_flags->val &= ~opts->bit;
-        else
-                tracer_flags->val |= opts->bit;
-
-        return 0;
+        return -EINVAL;
 }
 
 static void set_tracer_flags(unsigned int mask, int enabled)
@@ -2394,7 +2395,7 @@ tracing_trace_options_write(struct file *filp, const char __user *ubuf,
                         size_t cnt, loff_t *ppos)
 {
         char buf[64];
-        char *cmp = buf;
+        char *cmp;
         int neg = 0;
         int ret;
         int i;
@@ -2406,16 +2407,15 @@ tracing_trace_options_write(struct file *filp, const char __user *ubuf,
                 return -EFAULT;
 
         buf[cnt] = 0;
+        cmp = strstrip(buf);
 
-        if (strncmp(buf, "no", 2) == 0) {
+        if (strncmp(cmp, "no", 2) == 0) {
                 neg = 1;
                 cmp += 2;
         }
 
         for (i = 0; trace_options[i]; i++) {
-                int len = strlen(trace_options[i]);
-
-                if (strncmp(cmp, trace_options[i], len) == 0) {
+                if (strcmp(cmp, trace_options[i]) == 0) {
                         set_tracer_flags(1 << i, !neg);
                         break;
                 }
@@ -3927,39 +3927,16 @@ trace_options_write(struct file *filp, const char __user *ubuf, size_t cnt,
         if (ret < 0)
                 return ret;
 
-        ret = 0;
-        switch (val) {
-        case 0:
-                /* do nothing if already cleared */
-                if (!(topt->flags->val & topt->opt->bit))
-                        break;
-
-                mutex_lock(&trace_types_lock);
-                if (current_trace->set_flag)
-                        ret = current_trace->set_flag(topt->flags->val,
-                                                      topt->opt->bit, 0);
-                mutex_unlock(&trace_types_lock);
-                if (ret)
-                        return ret;
-                topt->flags->val &= ~topt->opt->bit;
-                break;
-        case 1:
-                /* do nothing if already set */
-                if (topt->flags->val & topt->opt->bit)
-                        break;
+        if (val != 0 && val != 1)
+                return -EINVAL;
 
+        if (!!(topt->flags->val & topt->opt->bit) != val) {
                 mutex_lock(&trace_types_lock);
-                if (current_trace->set_flag)
-                        ret = current_trace->set_flag(topt->flags->val,
-                                                      topt->opt->bit, 1);
+                ret = __set_tracer_option(current_trace, topt->flags,
+                                          topt->opt, val);
                 mutex_unlock(&trace_types_lock);
                 if (ret)
                         return ret;
-                topt->flags->val |= topt->opt->bit;
-                break;
-
-        default:
-                return -EINVAL;
         }
 
         *ppos += cnt;