drm/radeon: fix AGP userptr handling

AGP mappings are not cache coherent, so userptr support
won't work. Additional to that the AGP implementation uses
a different ttm_tt container structure so we run into
problems if we cast the pointer without checking if it's
the right type.

Signed-off-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/radeon/radeon_ttm.c b/drivers/gpu/drm/radeon/radeon_ttm.c
index eca2ce6..d73ea9c 100644 (file)
--- a/drivers/gpu/drm/radeon/radeon_ttm.c
+++ b/drivers/gpu/drm/radeon/radeon_ttm.c
@@ -675,10 +675,17 @@ static struct ttm_tt *radeon_ttm_tt_create(struct ttm_bo_device *bdev,
        return &gtt->ttm.ttm;
 }
 
+static struct radeon_ttm_tt *radeon_ttm_tt_to_gtt(struct ttm_tt *ttm)
+{
+       if (!ttm || ttm->func != &radeon_backend_func)
+               return NULL;
+       return (struct radeon_ttm_tt *)ttm;
+}
+
 static int radeon_ttm_tt_populate(struct ttm_tt *ttm)
 {
+       struct radeon_ttm_tt *gtt = radeon_ttm_tt_to_gtt(ttm);
        struct radeon_device *rdev;
-       struct radeon_ttm_tt *gtt = (void *)ttm;
        unsigned i;
        int r;
        bool slave = !!(ttm->page_flags & TTM_PAGE_FLAG_SG);
@@ -686,7 +693,7 @@ static int radeon_ttm_tt_populate(struct ttm_tt *ttm)
        if (ttm->state != tt_unpopulated)
                return 0;
 
-       if (gtt->userptr) {
+       if (gtt && gtt->userptr) {
                ttm->sg = kcalloc(1, sizeof(struct sg_table), GFP_KERNEL);
                if (!ttm->sg)
                        return -ENOMEM;
@@ -741,11 +748,11 @@ static int radeon_ttm_tt_populate(struct ttm_tt *ttm)
 static void radeon_ttm_tt_unpopulate(struct ttm_tt *ttm)
 {
        struct radeon_device *rdev;
-       struct radeon_ttm_tt *gtt = (void *)ttm;
+       struct radeon_ttm_tt *gtt = radeon_ttm_tt_to_gtt(ttm);
        unsigned i;
        bool slave = !!(ttm->page_flags & TTM_PAGE_FLAG_SG);
 
-       if (gtt->userptr) {
+       if (gtt && gtt->userptr) {
                kfree(ttm->sg);
                ttm->page_flags &= ~TTM_PAGE_FLAG_SG;
                return;
@@ -782,7 +789,7 @@ static void radeon_ttm_tt_unpopulate(struct ttm_tt *ttm)
 int radeon_ttm_tt_set_userptr(struct ttm_tt *ttm, uint64_t addr,
                              uint32_t flags)
 {
-       struct radeon_ttm_tt *gtt = (void *)ttm;
+       struct radeon_ttm_tt *gtt = radeon_ttm_tt_to_gtt(ttm);
 
        if (gtt == NULL)
                return -EINVAL;
@@ -795,7 +802,7 @@ int radeon_ttm_tt_set_userptr(struct ttm_tt *ttm, uint64_t addr,
 
 bool radeon_ttm_tt_has_userptr(struct ttm_tt *ttm)
 {
-       struct radeon_ttm_tt *gtt = (void *)ttm;
+       struct radeon_ttm_tt *gtt = radeon_ttm_tt_to_gtt(ttm);
 
        if (gtt == NULL)
                return false;
@@ -805,7 +812,7 @@ bool radeon_ttm_tt_has_userptr(struct ttm_tt *ttm)
 
 bool radeon_ttm_tt_is_readonly(struct ttm_tt *ttm)
 {
-       struct radeon_ttm_tt *gtt = (void *)ttm;
+       struct radeon_ttm_tt *gtt = radeon_ttm_tt_to_gtt(ttm);
 
        if (gtt == NULL)
                return false;