tracing: Use seq_*_private interface for some seq files

It's appropriate to use __seq_open_private interface to open
some of trace seq files, because it covers all steps we are
duplicating in tracing code - zallocating the iterator and
setting it as seq_file's private.

Using this for following files:
  trace
  available_filter_functions
  enabled_functions

Link: http://lkml.kernel.org/r/1335342219-2782-5-git-send-email-jolsa@redhat.com

Signed-off-by: Jiri Olsa <jolsa@redhat.com>

[
 Fixed warnings for:
   kernel/trace/trace.c: In function '__tracing_open':
   kernel/trace/trace.c:2418:11: warning: unused variable 'ret' [-Wunused-variable]
   kernel/trace/trace.c:2417:19: warning: unused variable 'm' [-Wunused-variable]
]

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

2 files changed, 16 insertions, 58 deletions

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 0fa92f677c92..cf81f27ce6c6 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -2469,57 +2469,35 @@ static int
 ftrace_avail_open(struct inode *inode, struct file *file)
 {
         struct ftrace_iterator *iter;
-        int ret;
 
         if (unlikely(ftrace_disabled))
                 return -ENODEV;
 
-        iter = kzalloc(sizeof(*iter), GFP_KERNEL);
-        if (!iter)
-                return -ENOMEM;
-
-        iter->pg = ftrace_pages_start;
-        iter->ops = &global_ops;
-
-        ret = seq_open(file, &show_ftrace_seq_ops);
-        if (!ret) {
-                struct seq_file *m = file->private_data;
-
-                m->private = iter;
-        } else {
-                kfree(iter);
+        iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
+        if (iter) {
+                iter->pg = ftrace_pages_start;
+                iter->ops = &global_ops;
         }
 
-        return ret;
+        return iter ? 0 : -ENOMEM;
 }
 
 static int
 ftrace_enabled_open(struct inode *inode, struct file *file)
 {
         struct ftrace_iterator *iter;
-        int ret;
 
         if (unlikely(ftrace_disabled))
                 return -ENODEV;
 
-        iter = kzalloc(sizeof(*iter), GFP_KERNEL);
-        if (!iter)
-                return -ENOMEM;
-
-        iter->pg = ftrace_pages_start;
-        iter->flags = FTRACE_ITER_ENABLED;
-        iter->ops = &global_ops;
-
-        ret = seq_open(file, &show_ftrace_seq_ops);
-        if (!ret) {
-                struct seq_file *m = file->private_data;
-
-                m->private = iter;
-        } else {
-                kfree(iter);
+        iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
+        if (iter) {
+                iter->pg = ftrace_pages_start;
+                iter->flags = FTRACE_ITER_ENABLED;
+                iter->ops = &global_ops;
         }
 
-        return ret;
+        return iter ? 0 : -ENOMEM;
 }
 
 static void ftrace_filter_reset(struct ftrace_hash *hash)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index f11a285ee5bb..4fb10ef727d3 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2413,15 +2413,13 @@ static struct trace_iterator *
 __tracing_open(struct inode *inode, struct file *file)
 {
         long cpu_file = (long) inode->i_private;
-        void *fail_ret = ERR_PTR(-ENOMEM);
         struct trace_iterator *iter;
-        struct seq_file *m;
-        int cpu, ret;
+        int cpu;
 
         if (tracing_disabled)
                 return ERR_PTR(-ENODEV);
 
-        iter = kzalloc(sizeof(*iter), GFP_KERNEL);
+        iter = __seq_open_private(file, &tracer_seq_ops, sizeof(*iter));
         if (!iter)
                 return ERR_PTR(-ENOMEM);
 
@@ -2478,32 +2476,15 @@ __tracing_open(struct inode *inode, struct file *file)
                 tracing_iter_reset(iter, cpu);
         }
 
-        ret = seq_open(file, &tracer_seq_ops);
-        if (ret < 0) {
-                fail_ret = ERR_PTR(ret);
-                goto fail_buffer;
-        }
-
-        m = file->private_data;
-        m->private = iter;
-
         mutex_unlock(&trace_types_lock);
 
         return iter;
 
- fail_buffer:
-        for_each_tracing_cpu(cpu) {
-                if (iter->buffer_iter[cpu])
-                        ring_buffer_read_finish(iter->buffer_iter[cpu]);
-        }
-        free_cpumask_var(iter->started);
-        tracing_start();
  fail:
         mutex_unlock(&trace_types_lock);
         kfree(iter->trace);
-        kfree(iter);
-
-        return fail_ret;
+        seq_release_private(inode, file);
+        return ERR_PTR(-ENOMEM);
 }
 
 int tracing_open_generic(struct inode *inode, struct file *filp)
@@ -2539,11 +2520,10 @@ static int tracing_release(struct inode *inode, struct file *file)
         tracing_start();
         mutex_unlock(&trace_types_lock);
 
-        seq_release(inode, file);
         mutex_destroy(&iter->mutex);
         free_cpumask_var(iter->started);
         kfree(iter->trace);
-        kfree(iter);
+        seq_release_private(inode, file);
         return 0;
 }