1 files changed, 18 insertions, 13 deletions

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 6ecfd108effa..6a89449f31d1 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -176,7 +176,8 @@ i915_gem_gtt_pwrite(struct drm_device *dev, struct drm_gem_object *obj,
         ssize_t remain;
         loff_t offset;
         char __user *user_data;
-        char *vaddr;
+        char __iomem *vaddr;
+        char *vaddr_atomic;
         int i, o, l;
         int ret = 0;
         unsigned long pfn;
@@ -219,16 +220,20 @@ i915_gem_gtt_pwrite(struct drm_device *dev, struct drm_gem_object *obj,
                 pfn = (dev->agp->base >> PAGE_SHIFT) + i;
 
 #ifdef CONFIG_HIGHMEM
-                /* kmap_atomic can't map IO pages on non-HIGHMEM kernels
+                /* This is a workaround for the low performance of iounmap
+                 * (approximate 10% cpu cost on normal 3D workloads).
+                 * kmap_atomic on HIGHMEM kernels happens to let us map card
+                 * memory without taking IPIs.  When the vmap rework lands
+                 * we should be able to dump this hack.
                  */
-                vaddr = kmap_atomic_pfn(pfn, KM_USER0);
+                vaddr_atomic = kmap_atomic_pfn(pfn, KM_USER0);
 #if WATCH_PWRITE
                 DRM_INFO("pwrite i %d o %d l %d pfn %ld vaddr %p\n",
-                         i, o, l, pfn, vaddr);
+                         i, o, l, pfn, vaddr_atomic);
 #endif
-                unwritten = __copy_from_user_inatomic_nocache(vaddr + o,
+                unwritten = __copy_from_user_inatomic_nocache(vaddr_atomic + o,
                                                               user_data, l);
-                kunmap_atomic(vaddr, KM_USER0);
+                kunmap_atomic(vaddr_atomic, KM_USER0);
 
                 if (unwritten)
 #endif /* CONFIG_HIGHMEM */
@@ -271,7 +276,7 @@ fail:
         return ret;
 }
 
-int
+static int
 i915_gem_shmem_pwrite(struct drm_device *dev, struct drm_gem_object *obj,
                       struct drm_i915_gem_pwrite *args,
                       struct drm_file *file_priv)
@@ -587,7 +592,7 @@ i915_add_request(struct drm_device *dev, uint32_t flush_domains)
  * Ensures that all commands in the ring are finished
  * before signalling the CPU
  */
-uint32_t
+static uint32_t
 i915_retire_commands(struct drm_device *dev)
 {
         drm_i915_private_t *dev_priv = dev->dev_private;
@@ -734,7 +739,7 @@ i915_gem_retire_work_handler(struct work_struct *work)
  * Waits for a sequence number to be signaled, and cleans up the
  * request and object lists appropriately for that event.
  */
-int
+static int
 i915_wait_request(struct drm_device *dev, uint32_t seqno)
 {
         drm_i915_private_t *dev_priv = dev->dev_private;
@@ -1483,7 +1488,7 @@ i915_gem_object_pin_and_relocate(struct drm_gem_object *obj,
         struct drm_i915_gem_object *obj_priv = obj->driver_private;
         int i, ret;
         uint32_t last_reloc_offset = -1;
-        void *reloc_page = NULL;
+        void __iomem *reloc_page = NULL;
 
         /* Choose the GTT offset for our buffer and put it there. */
         ret = i915_gem_object_pin(obj, (uint32_t) entry->alignment);
@@ -1500,8 +1505,8 @@ i915_gem_object_pin_and_relocate(struct drm_gem_object *obj,
         for (i = 0; i < entry->relocation_count; i++) {
                 struct drm_gem_object *target_obj;
                 struct drm_i915_gem_object *target_obj_priv;
-                uint32_t reloc_val, reloc_offset, *reloc_entry;
-                int ret;
+                uint32_t reloc_val, reloc_offset;
+                uint32_t __iomem *reloc_entry;
 
                 ret = copy_from_user(&reloc, relocs + i, sizeof(reloc));
                 if (ret != 0) {
@@ -1624,7 +1629,7 @@ i915_gem_object_pin_and_relocate(struct drm_gem_object *obj,
                         }
                 }
 
-                reloc_entry = (uint32_t *)((char *)reloc_page +
+                reloc_entry = (uint32_t __iomem *)(reloc_page +
                                            (reloc_offset & (PAGE_SIZE - 1)));
                 reloc_val = target_obj_priv->gtt_offset + reloc.delta;