Revert "drm/vgem: Implement mmap as GEM object function"

Commit 375cca1cfeb5 ("drm/vgem: Implement mmap as GEM object function")
broke several IGT tests in vgem_basic. [1] Attempts to fix the issue
have not worked out so far. [2][3] Revert the change for now.

Note that there is a patch that converts vgem to shmem helpers. [4]
Merging this change would be preferable to modifying vgem's mmap code.

v2:
	* fix spelling error in commit message (Daniel)

[1] https://intel-gfx-ci.01.org/tree/drm-tip/igt@vgem_basic@unload.html
[2] https://lore.kernel.org/intel-gfx/20210709154256.12005-1-tzimmermann@suse.de/
[3] https://lore.kernel.org/intel-gfx/20210712123321.3658-1-tzimmermann@suse.de/
[4] https://patchwork.freedesktop.org/series/90671/

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Fixes: 375cca1cfeb5 ("drm/vgem: Implement mmap as GEM object function")
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Christian König <christian.koenig@amd.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Melissa Wen <melissa.srw@gmail.com>
Cc: Qinglang Miao <miaoqinglang@huawei.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210713090235.26372-1-tzimmermann@suse.de

diff --git a/drivers/gpu/drm/vgem/vgem_drv.c b/drivers/gpu/drm/vgem/vgem_drv.c
index df634aa526387134ad34b855cbc2d38bd3547787..bf38a7e319d14d4c638e8204792013c6b2da6d80 100644 (file)
--- a/drivers/gpu/drm/vgem/vgem_drv.c
+++ b/drivers/gpu/drm/vgem/vgem_drv.c
@@ -239,7 +239,32 @@ static struct drm_ioctl_desc vgem_ioctls[] = {
        DRM_IOCTL_DEF_DRV(VGEM_FENCE_SIGNAL, vgem_fence_signal_ioctl, DRM_RENDER_ALLOW),
 };
 
-DEFINE_DRM_GEM_FOPS(vgem_driver_fops);
+static int vgem_mmap(struct file *filp, struct vm_area_struct *vma)
+{
+       unsigned long flags = vma->vm_flags;
+       int ret;
+
+       ret = drm_gem_mmap(filp, vma);
+       if (ret)
+               return ret;
+
+       /* Keep the WC mmaping set by drm_gem_mmap() but our pages
+        * are ordinary and not special.
+        */
+       vma->vm_flags = flags | VM_DONTEXPAND | VM_DONTDUMP;
+       return 0;
+}
+
+static const struct file_operations vgem_driver_fops = {
+       .owner          = THIS_MODULE,
+       .open           = drm_open,
+       .mmap           = vgem_mmap,
+       .poll           = drm_poll,
+       .read           = drm_read,
+       .unlocked_ioctl = drm_ioctl,
+       .compat_ioctl   = drm_compat_ioctl,
+       .release        = drm_release,
+};
 
 static struct page **vgem_pin_pages(struct drm_vgem_gem_object *bo)
 {
@@ -362,12 +387,24 @@ static void vgem_prime_vunmap(struct drm_gem_object *obj, struct dma_buf_map *ma
        vgem_unpin_pages(bo);
 }
 
-static int vgem_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
+static int vgem_prime_mmap(struct drm_gem_object *obj,
+                          struct vm_area_struct *vma)
 {
+       int ret;
+
+       if (obj->size < vma->vm_end - vma->vm_start)
+               return -EINVAL;
+
+       if (!obj->filp)
+               return -ENODEV;
+
+       ret = call_mmap(obj->filp, vma);
+       if (ret)
+               return ret;
+
        vma_set_file(vma, obj->filp);
        vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
        vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
-       vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);
 
        return 0;
 }
@@ -379,7 +416,6 @@ static const struct drm_gem_object_funcs vgem_gem_object_funcs = {
        .get_sg_table = vgem_prime_get_sg_table,
        .vmap = vgem_prime_vmap,
        .vunmap = vgem_prime_vunmap,
-       .mmap = vgem_prime_mmap,
        .vm_ops = &vgem_gem_vm_ops,
 };
 
@@ -397,7 +433,7 @@ static const struct drm_driver vgem_driver = {
        .prime_fd_to_handle = drm_gem_prime_fd_to_handle,
        .gem_prime_import = vgem_prime_import,
        .gem_prime_import_sg_table = vgem_prime_import_sg_table,
-       .gem_prime_mmap = drm_gem_prime_mmap,
+       .gem_prime_mmap = vgem_prime_mmap,
 
        .name   = DRIVER_NAME,
        .desc   = DRIVER_DESC,