drm: Split out the mm declarations in a separate header. Add atomic operations.

this is a TTM preparation patch, it rearranges the mm and
add operations needed to do mm operations in atomic context.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

3 files changed, 228 insertions, 64 deletions

diff --git a/drivers/gpu/drm/drm_mm.c b/drivers/gpu/drm/drm_mm.c
index 367c590ffbba..7819fd930a51 100644
--- a/drivers/gpu/drm/drm_mm.c
+++ b/drivers/gpu/drm/drm_mm.c
@@ -42,8 +42,11 @@
  */
 
 #include "drmP.h"
+#include "drm_mm.h"
 #include <linux/slab.h>
 
+#define MM_UNUSED_TARGET 4
+
 unsigned long drm_mm_tail_space(struct drm_mm *mm)
 {
         struct list_head *tail_node;
@@ -74,16 +77,62 @@ int drm_mm_remove_space_from_tail(struct drm_mm *mm, unsigned long size)
         return 0;
 }
 
+static struct drm_mm_node *drm_mm_kmalloc(struct drm_mm *mm, int atomic)
+{
+        struct drm_mm_node *child;
+
+        if (atomic)
+                child = kmalloc(sizeof(*child), GFP_ATOMIC);
+        else
+                child = kmalloc(sizeof(*child), GFP_KERNEL);
+
+        if (unlikely(child == NULL)) {
+                spin_lock(&mm->unused_lock);
+                if (list_empty(&mm->unused_nodes))
+                        child = NULL;
+                else {
+                        child =
+                            list_entry(mm->unused_nodes.next,
+                                       struct drm_mm_node, fl_entry);
+                        list_del(&child->fl_entry);
+                        --mm->num_unused;
+                }
+                spin_unlock(&mm->unused_lock);
+        }
+        return child;
+}
+
+int drm_mm_pre_get(struct drm_mm *mm)
+{
+        struct drm_mm_node *node;
+
+        spin_lock(&mm->unused_lock);
+        while (mm->num_unused < MM_UNUSED_TARGET) {
+                spin_unlock(&mm->unused_lock);
+                node = kmalloc(sizeof(*node), GFP_KERNEL);
+                spin_lock(&mm->unused_lock);
+
+                if (unlikely(node == NULL)) {
+                        int ret = (mm->num_unused < 2) ? -ENOMEM : 0;
+                        spin_unlock(&mm->unused_lock);
+                        return ret;
+                }
+                ++mm->num_unused;
+                list_add_tail(&node->fl_entry, &mm->unused_nodes);
+        }
+        spin_unlock(&mm->unused_lock);
+        return 0;
+}
+EXPORT_SYMBOL(drm_mm_pre_get);
 
 static int drm_mm_create_tail_node(struct drm_mm *mm,
-                            unsigned long start,
-                            unsigned long size)
+                                   unsigned long start,
+                                   unsigned long size, int atomic)
 {
         struct drm_mm_node *child;
 
-        child = (struct drm_mm_node *)
-                drm_alloc(sizeof(*child), DRM_MEM_MM);
-        if (!child)
+        child = drm_mm_kmalloc(mm, atomic);
+        if (unlikely(child == NULL))
                 return -ENOMEM;
 
         child->free = 1;
@@ -97,8 +146,7 @@ static int drm_mm_create_tail_node(struct drm_mm *mm,
         return 0;
 }
 
-
-int drm_mm_add_space_to_tail(struct drm_mm *mm, unsigned long size)
+int drm_mm_add_space_to_tail(struct drm_mm *mm, unsigned long size, int atomic)
 {
         struct list_head *tail_node;
         struct drm_mm_node *entry;
@@ -106,20 +154,21 @@ int drm_mm_add_space_to_tail(struct drm_mm *mm, unsigned long size)
         tail_node = mm->ml_entry.prev;
         entry = list_entry(tail_node, struct drm_mm_node, ml_entry);
         if (!entry->free) {
-                return drm_mm_create_tail_node(mm, entry->start + entry->size, size);
+                return drm_mm_create_tail_node(mm, entry->start + entry->size,
+                                               size, atomic);
         }
         entry->size += size;
         return 0;
 }
 
 static struct drm_mm_node *drm_mm_split_at_start(struct drm_mm_node *parent,
-                                            unsigned long size)
+                                                 unsigned long size,
+                                                 int atomic)
 {
         struct drm_mm_node *child;
 
-        child = (struct drm_mm_node *)
-                drm_alloc(sizeof(*child), DRM_MEM_MM);
-        if (!child)
+        child = drm_mm_kmalloc(parent->mm, atomic);
+        if (unlikely(child == NULL))
                 return NULL;
 
         INIT_LIST_HEAD(&child->fl_entry);
@@ -151,8 +200,9 @@ struct drm_mm_node *drm_mm_get_block(struct drm_mm_node * parent,
                 tmp = parent->start % alignment;
 
         if (tmp) {
-                align_splitoff = drm_mm_split_at_start(parent, alignment - tmp);
-                if (!align_splitoff)
+                align_splitoff =
+                    drm_mm_split_at_start(parent, alignment - tmp, 0);
+                if (unlikely(align_splitoff == NULL))
                         return NULL;
         }
 
@@ -161,7 +211,7 @@ struct drm_mm_node *drm_mm_get_block(struct drm_mm_node * parent,
                 parent->free = 0;
                 return parent;
         } else {
-                child = drm_mm_split_at_start(parent, size);
+                child = drm_mm_split_at_start(parent, size, 0);
         }
 
         if (align_splitoff)
@@ -169,14 +219,49 @@ struct drm_mm_node *drm_mm_get_block(struct drm_mm_node * parent,
 
         return child;
 }
+
 EXPORT_SYMBOL(drm_mm_get_block);
 
+struct drm_mm_node *drm_mm_get_block_atomic(struct drm_mm_node *parent,
+                                            unsigned long size,
+                                            unsigned alignment)
+{
+
+        struct drm_mm_node *align_splitoff = NULL;
+        struct drm_mm_node *child;
+        unsigned tmp = 0;
+
+        if (alignment)
+                tmp = parent->start % alignment;
+
+        if (tmp) {
+                align_splitoff =
+                    drm_mm_split_at_start(parent, alignment - tmp, 1);
+                if (unlikely(align_splitoff == NULL))
+                        return NULL;
+        }
+
+        if (parent->size == size) {
+                list_del_init(&parent->fl_entry);
+                parent->free = 0;
+                return parent;
+        } else {
+                child = drm_mm_split_at_start(parent, size, 1);
+        }
+
+        if (align_splitoff)
+                drm_mm_put_block(align_splitoff);
+