Since

commit 96667f8a4382db9ed042332ca6ee165ae9b91307
Author: Daniel Vetter <daniel.vet...@ffwll.ch>
Date:   Fri Nov 27 17:41:21 2020 +0100

    mm: Close race in generic_access_phys

it is race-free and can therefore be safely used for dynamic mappings
like we have too.

Cc: Jon Bloomfield <jon.bloomfi...@intel.com>
Signed-off-by: Daniel Vetter <daniel.vet...@intel.com>
Cc: Daniel Vetter <daniel.vet...@ffwll.ch>
Cc: "Thomas Hellström" <thomas.hellst...@linux.intel.com>
Cc: Chris Wilson <ch...@chris-wilson.co.uk>
Cc: Maarten Lankhorst <maarten.lankho...@linux.intel.com>
Cc: Andrew Morton <a...@linux-foundation.org>
Cc: "Christian König" <christian.koe...@amd.com>
Cc: "Ville Syrjälä" <ville.syrj...@linux.intel.com>
Cc: Michel Lespinasse <wal...@google.com>
---
 drivers/gpu/drm/i915/gem/i915_gem_mman.c | 60 +++---------------------
 1 file changed, 6 insertions(+), 54 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_mman.c 
b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
index f6fe5cb01438..717798293044 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_mman.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
@@ -414,58 +414,6 @@ static vm_fault_t vm_fault_gtt(struct vm_fault *vmf)
        return i915_error_to_vmf_fault(ret);
 }
 
-static int
-vm_access(struct vm_area_struct *area, unsigned long addr,
-         void *buf, int len, int write)
-{
-       struct i915_mmap_offset *mmo = area->vm_private_data;
-       struct drm_i915_gem_object *obj = mmo->obj;
-       struct i915_gem_ww_ctx ww;
-       void *vaddr;
-       int err = 0;
-
-       if (i915_gem_object_is_readonly(obj) && write)
-               return -EACCES;
-
-       addr -= area->vm_start;
-       if (addr >= obj->base.size)
-               return -EINVAL;
-
-       i915_gem_ww_ctx_init(&ww, true);
-retry:
-       err = i915_gem_object_lock(obj, &ww);
-       if (err)
-               goto out;
-
-       /* As this is primarily for debugging, let's focus on simplicity */
-       vaddr = i915_gem_object_pin_map(obj, I915_MAP_FORCE_WC);
-       if (IS_ERR(vaddr)) {
-               err = PTR_ERR(vaddr);
-               goto out;
-       }
-
-       if (write) {
-               memcpy(vaddr + addr, buf, len);
-               __i915_gem_object_flush_map(obj, addr, len);
-       } else {
-               memcpy(buf, vaddr + addr, len);
-       }
-
-       i915_gem_object_unpin_map(obj);
-out:
-       if (err == -EDEADLK) {
-               err = i915_gem_ww_ctx_backoff(&ww);
-               if (!err)
-                       goto retry;
-       }
-       i915_gem_ww_ctx_fini(&ww);
-
-       if (err)
-               return err;
-
-       return len;
-}
-
 void __i915_gem_object_release_mmap_gtt(struct drm_i915_gem_object *obj)
 {
        struct i915_vma *vma;
@@ -801,14 +749,18 @@ static void vm_close(struct vm_area_struct *vma)
 
 static const struct vm_operations_struct vm_ops_gtt = {
        .fault = vm_fault_gtt,
-       .access = vm_access,
+#ifdef CONFIG_HAVE_IOREMAP_PROT
+       .access = generic_access_phys
+#endif
        .open = vm_open,
        .close = vm_close,
 };
 
 static const struct vm_operations_struct vm_ops_cpu = {
        .fault = vm_fault_cpu,
-       .access = vm_access,
+#ifdef CONFIG_HAVE_IOREMAP_PROT
+       .access = generic_access_phys
+#endif
        .open = vm_open,
        .close = vm_close,
 };
-- 
2.31.0

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