drm/i915: introduce i915_error_state_buf_init

Make function for struct i915_error_state_buf initialization
and export it, for sysfs and debugfs.
Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_debugfs.c

@@ -1028,38 +1028,48 @@ static int i915_error_state_release(struct inode *inode, struct file *file)
 	return 0;
 }
 
-static ssize_t i915_error_state_read(struct file *file, char __user *userbuf,
-				     size_t count, loff_t *pos)
+int i915_error_state_buf_init(struct drm_i915_error_state_buf *ebuf,
+			      size_t count, loff_t pos)
 {
-	struct i915_error_state_file_priv *error_priv = file->private_data;
-	struct drm_i915_error_state_buf error_str;
-	loff_t tmp_pos = 0;
-	ssize_t ret_count = 0;
-	int ret = 0;
-
-	memset(&error_str, 0, sizeof(error_str));
+	memset(ebuf, 0, sizeof(*ebuf));
 
 	/* We need to have enough room to store any i915_error_state printf
 	 * so that we can move it to start position.
 	 */
-	error_str.size = count + 1 > PAGE_SIZE ? count + 1 : PAGE_SIZE;
-	error_str.buf = kmalloc(error_str.size,
+	ebuf->size = count + 1 > PAGE_SIZE ? count + 1 : PAGE_SIZE;
+	ebuf->buf = kmalloc(ebuf->size,
 				GFP_TEMPORARY | __GFP_NORETRY | __GFP_NOWARN);
 
-	if (error_str.buf == NULL) {
-		error_str.size = PAGE_SIZE;
-		error_str.buf = kmalloc(error_str.size, GFP_TEMPORARY);
+	if (ebuf->buf == NULL) {
+		ebuf->size = PAGE_SIZE;
+		ebuf->buf = kmalloc(ebuf->size, GFP_TEMPORARY);
 	}
 
-	if (error_str.buf == NULL) {
-		error_str.size = 128;
-		error_str.buf = kmalloc(error_str.size, GFP_TEMPORARY);
+	if (ebuf->buf == NULL) {
+		ebuf->size = 128;
+		ebuf->buf = kmalloc(ebuf->size, GFP_TEMPORARY);
 	}
 
-	if (error_str.buf == NULL)
+	if (ebuf->buf == NULL)
 		return -ENOMEM;
 
-	error_str.start = *pos;
+	ebuf->start = pos;
+
+	return 0;
+}
+
+static ssize_t i915_error_state_read(struct file *file, char __user *userbuf,
+				     size_t count, loff_t *pos)
+{
+	struct i915_error_state_file_priv *error_priv = file->private_data;
+	struct drm_i915_error_state_buf error_str;
+	loff_t tmp_pos = 0;
+	ssize_t ret_count = 0;
+	int ret;
+
+	ret = i915_error_state_buf_init(&error_str, count, *pos);
+	if (ret)
+		return ret;
 
 	ret = i915_error_state_to_str(&error_str, error_priv);
 	if (ret)
@@ -1074,7 +1084,7 @@ static ssize_t i915_error_state_read(struct file *file, char __user *userbuf,
 	else
 		*pos = error_str.start + ret_count;
 out:
-	kfree(error_str.buf);
+	i915_error_state_buf_release(&error_str);
 	return ret ?: ret_count;
 }
 

drivers/gpu/drm/i915/i915_drv.h

@@ -1931,6 +1931,13 @@ int i915_error_state_to_str(struct drm_i915_error_state_buf *estr,
 void i915_error_state_get(struct drm_device *dev,
 			  struct i915_error_state_file_priv *error_priv);
 void i915_error_state_put(struct i915_error_state_file_priv *error_priv);
+int i915_error_state_buf_init(struct drm_i915_error_state_buf *eb,
+			      size_t count, loff_t pos);
+static inline void i915_error_state_buf_release(
+	struct drm_i915_error_state_buf *eb)
+{
+	kfree(eb->buf);
+}
 
 /* i915_suspend.c */
 extern int i915_save_state(struct drm_device *dev);