ftrace: Introduce struct ftrace_graph_data

The struct ftrace_graph_data is for generalizing the access to
set_graph_function file.  This is a preparation for adding support to
set_graph_notrace.

Link: http://lkml.kernel.org/r/1381739066-7531-3-git-send-email-namhyung@kernel.org

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 62 insertions, 19 deletions

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index a77e4a0142ee..0ff3449b4272 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -3641,7 +3641,7 @@ __setup("ftrace_filter=", set_ftrace_filter);
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
-static int ftrace_set_func(unsigned long *array, int *idx, char *buffer);
+static int ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer);
 
 static int __init set_graph_function(char *str)
 {
@@ -3659,7 +3659,7 @@ static void __init set_ftrace_early_graph(char *buf)
                 func = strsep(&buf, ",");
                 /* we allow only one expression at a time */
                 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
-                                      func);
+                                      FTRACE_GRAPH_MAX_FUNCS, func);
                 if (ret)
                         printk(KERN_DEBUG "ftrace: function %s not "
                                           "traceable\n", func);
@@ -3778,12 +3778,21 @@ static DEFINE_MUTEX(graph_lock);
 int ftrace_graph_count;
 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
 
+struct ftrace_graph_data {
+        unsigned long *table;
+        size_t size;
+        int *count;
+        const struct seq_operations *seq_ops;
+};
+
 static void *
 __g_next(struct seq_file *m, loff_t *pos)
 {
-        if (*pos >= ftrace_graph_count)
+        struct ftrace_graph_data *fgd = m->private;
+
+        if (*pos >= *fgd->count)
                 return NULL;
-        return &ftrace_graph_funcs[*pos];
+        return &fgd->table[*pos];
 }
 
 static void *
@@ -3795,10 +3804,12 @@ g_next(struct seq_file *m, void *v, loff_t *pos)
 
 static void *g_start(struct seq_file *m, loff_t *pos)
 {
+        struct ftrace_graph_data *fgd = m->private;
+
         mutex_lock(&graph_lock);
 
         /* Nothing, tell g_show to print all functions are enabled */
-        if (!ftrace_graph_count && !*pos)
+        if (!*fgd->count && !*pos)
                 return (void *)1;
 
         return __g_next(m, pos);
@@ -3834,37 +3845,68 @@ static const struct seq_operations ftrace_graph_seq_ops = {
 };
 
 static int
-ftrace_graph_open(struct inode *inode, struct file *file)
+__ftrace_graph_open(struct inode *inode, struct file *file,
+                    struct ftrace_graph_data *fgd)
 {
         int ret = 0;
 
-        if (unlikely(ftrace_disabled))
-                return -ENODEV;
-
         mutex_lock(&graph_lock);
         if ((file->f_mode & FMODE_WRITE) &&
             (file->f_flags & O_TRUNC)) {
-                ftrace_graph_count = 0;
-                memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
+                *fgd->count = 0;
+                memset(fgd->table, 0, fgd->size * sizeof(*fgd->table));
         }
         mutex_unlock(&graph_lock);
 
-        if (file->f_mode & FMODE_READ)
-                ret = seq_open(file, &ftrace_graph_seq_ops);
+        if (file->f_mode & FMODE_READ) {
+                ret = seq_open(file, fgd->seq_ops);
+                if (!ret) {
+                        struct seq_file *m = file->private_data;
+                        m->private = fgd;
+                }
+        } else
+                file->private_data = fgd;
 
         return ret;
 }
 
 static int
+ftrace_graph_open(struct inode *inode, struct file *file)
+{
+        struct ftrace_graph_data *fgd;
+
+        if (unlikely(ftrace_disabled))
+                return -ENODEV;
+
+        fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
+        if (fgd == NULL)
+                return -ENOMEM;
+
+        fgd->table = ftrace_graph_funcs;
+        fgd->size = FTRACE_GRAPH_MAX_FUNCS;
+        fgd->count = &ftrace_graph_count;
+        fgd->seq_ops = &ftrace_graph_seq_ops;
+
+        return __ftrace_graph_open(inode, file, fgd);
+}
+
+static int
 ftrace_graph_release(struct inode *inode, struct file *file)
 {
-        if (file->f_mode & FMODE_READ)
+        if (file->f_mode & FMODE_READ) {
+                struct seq_file *m = file->private_data;
+
+                kfree(m->private);
                 seq_release(inode, file);
+        } else {
+                kfree(file->private_data);
+        }
+
         return 0;
 }
 
 static int
-ftrace_set_func(unsigned long *array, int *idx, char *buffer)
+ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer)
 {
         struct dyn_ftrace *rec;
         struct ftrace_page *pg;
@@ -3877,7 +3919,7 @@ ftrace_set_func(unsigned long *array, int *idx, char *buffer)
 
         /* decode regex */
         type = filter_parse_regex(buffer, strlen(buffer), &search, &not);
-        if (!not && *idx >= FTRACE_GRAPH_MAX_FUNCS)
+        if (!not && *idx >= size)
                 return -EBUSY;
 
         search_len = strlen(search);
@@ -3905,7 +3947,7 @@ ftrace_set_func(unsigned long *array, int *idx, char *buffer)
                                 fail = 0;
                                 if (!exists) {
                                         array[(*idx)++] = rec->ip;
-                                        if (*idx >= FTRACE_GRAPH_MAX_FUNCS)
+                                        if (*idx >= size)
                                                 goto out;
                                 }
                         } else {
@@ -3932,6 +3974,7 @@ ftrace_graph_write(struct file *file, const char __user *ubuf,
 {
         struct trace_parser parser;
         ssize_t read, ret;
+        struct ftrace_graph_data *fgd = file->private_data;
 
         if (!cnt)
                 return 0;
@@ -3949,8 +3992,8 @@ ftrace_graph_write(struct file *file, const char __user *ubuf,
                 parser.buffer[parser.idx] = 0;
 
                 /* we allow only one expression at a time */
-                ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
-                                        parser.buffer);
+                ret = ftrace_set_func(fgd->table, fgd->count, fgd->size,
+                                      parser.buffer);
                 if (ret)
                         goto out_free;
         }