From c488e25ceb421c6f84f110d786d9814ac4dba1b2 Mon Sep 17 00:00:00 2001
From: Thomas Hellstrom <thomas-at-tungstengraphics-dot-com>
Date: Fri, 25 Aug 2006 20:03:39 +0200
Subject: More ioctl stubs. Buffer object locking order documentation.

---
 linux-core/drm_bo.c  | 63 +++++++++++++++++++++++++++++++++++++++++++++++-----
 linux-core/drm_ttm.c |  2 +-
 linux-core/drm_ttm.h |  3 +--
 shared-core/drm.h    |  8 +++----
 4 files changed, 63 insertions(+), 13 deletions(-)

diff --git a/linux-core/drm_bo.c b/linux-core/drm_bo.c
index 6a677578..847b0406 100644
--- a/linux-core/drm_bo.c
+++ b/linux-core/drm_bo.c
@@ -31,6 +31,30 @@
 
 #include "drmP.h"
 
+/*
+ * Buffer object locking policy:
+ * Lock dev->struct_mutex;
+ * Increase usage
+ * Unlock dev->struct_mutex;
+ * Lock buffer->mutex;
+ * Do whatever you want;
+ * Unlock buffer->mutex;
+ * Decrease usage. Call destruction if zero.
+ *
+ * User object visibility ups usage just once, since it has its own 
+ * refcounting.
+ *
+ * Destruction:
+ * lock dev->struct_mutex;
+ * Verify that usage is zero. Otherwise unlock and continue.
+ * Destroy object.
+ * unlock dev->struct_mutex;
+ *
+ * Mutex and spinlock locking orders:
+ * 1.) Buffer mutex
+ * 2.) Refer to ttm locking orders.
+ */
+
 int drm_fence_buffer_objects(drm_file_t *priv)
 {
 	drm_device_t *dev = priv->head->dev;
@@ -277,11 +301,35 @@ int drm_bo_alloc_space(drm_device_t *dev, int tt, drm_buffer_object_t *buf)
 }
 #endif
 	
-static int drm_do_bo_ioctl(drm_file_t *priv, int num_requests, void __user *data)
+static int drm_do_bo_ioctl(drm_file_t *priv, int num_requests, 
+			   drm_bo_arg_data_t __user *data)
 {
-	return 0;
+	drm_bo_arg_data_t arg;
+	drm_bo_arg_request_t *req = &arg.req;
+	drm_bo_arg_reply_t rep;
+	int i, ret;
+	
+	for (i=0; i<num_requests; ++i) {
+		rep.ret = 0;
+		ret = copy_from_user(&arg, (void __user *) data, sizeof(arg));
+		if (ret) {
+			rep.ret = -EFAULT;
+			goto out_loop;
+		}
+
+		arg.rep = rep;
+		data++;
+	out_loop:
+		arg.rep = rep;
+		ret = copy_to_user((void __user *) data, &arg, sizeof(arg));
+		if (!ret)
+			++i;
+		break;
+	}
+	return i;
 }
 
+
 int drm_bo_ioctl(DRM_IOCTL_ARGS)
 {
 	DRM_DEVICE;
@@ -299,13 +347,16 @@ int drm_bo_ioctl(DRM_IOCTL_ARGS)
 
 	switch(arg.op) {
 	case drm_op_bo:
-		return drm_do_bo_ioctl(priv, arg.num_requests, 
-				       (void __user *) data_ptr);
+		arg.num_requests = drm_do_bo_ioctl(priv, arg.num_requests, 
+						   (drm_bo_arg_data_t __user *) 
+						   data_ptr);
+		break;
 	case drm_op_ttm:
-		return drm_ttm_ioctl(priv, arg.num_requests, 
-				     (drm_ttm_arg_t __user *) data_ptr);
+		return drm_ttm_ioctl(priv, (drm_ttm_arg_t __user *) 
+				     data_ptr);
 	}
 
+	DRM_COPY_TO_USER_IOCTL((void __user *) data, arg, sizeof(arg));
 	return 0;
 }
 	
diff --git a/linux-core/drm_ttm.c b/linux-core/drm_ttm.c
index 46878a7d..05bae7de 100644
--- a/linux-core/drm_ttm.c
+++ b/linux-core/drm_ttm.c
@@ -799,7 +799,7 @@ int drm_add_ttm(drm_device_t * dev, unsigned size, drm_map_list_t ** maplist)
 	return 0;
 }
 
-int drm_ttm_ioctl(drm_file_t *priv, int num_requests, drm_ttm_arg_t __user *data)
+int drm_ttm_ioctl(drm_file_t *priv, drm_ttm_arg_t __user *data)
 {
 	return 0;
 }
diff --git a/linux-core/drm_ttm.h b/linux-core/drm_ttm.h
index 81006c3c..5a7569ff 100644
--- a/linux-core/drm_ttm.h
+++ b/linux-core/drm_ttm.h
@@ -148,8 +148,7 @@ extern int drm_destroy_ttm(drm_ttm_t * ttm);
 extern void drm_user_destroy_region(drm_ttm_backend_list_t * entry);
 extern int drm_ttm_add_mm_to_list(drm_ttm_t * ttm, struct mm_struct *mm);
 extern void drm_ttm_delete_mm(drm_ttm_t * ttm, struct mm_struct *mm);
-extern int drm_ttm_ioctl(drm_file_t *priv, int num_requests, 
-			 drm_ttm_arg_t __user *data);
+extern int drm_ttm_ioctl(drm_file_t *priv, drm_ttm_arg_t __user *data);
 
 #define DRM_MASK_VAL(dest, mask, val)			\
   (dest) = ((dest) & ~(mask)) | ((val) & (mask));
diff --git a/shared-core/drm.h b/shared-core/drm.h
index fb18b5c5..feadfc67 100644
--- a/shared-core/drm.h
+++ b/shared-core/drm.h
@@ -740,10 +740,10 @@ typedef struct drm_bo_arg_reply {
 }drm_bo_arg_reply_t;
 	
 
-typedef union {
-	drm_bo_arg_request_t bo_req;
-	drm_bo_arg_reply_t bo_rep;
-}drm_bo_arg_data;
+typedef union drm_bo_arg_data {
+	drm_bo_arg_request_t req;
+	drm_bo_arg_reply_t rep;
+} drm_bo_arg_data_t;
 
 
 /**
-- 
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