drm/i915: Fix phys pwrite for struct_mutex-less operation

Since commit fe115628d567 ("drm/i915: Implement pwrite without
struct-mutex") the lowlevel pwrite calls are now called without the
protection of struct_mutex, but pwrite_phys was still asserting that it
held the struct_mutex and later tried to drop and relock it.

Fixes: fe115628d567 ("drm/i915: Implement pwrite without struct-mutex")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: <drm-intel-fixes@lists.freedesktop.org>
Link: http://patchwork.freedesktop.org/patch/msgid/20170106152240.5793-1-chris@chris-wilson.co.uk
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
(cherry picked from commit 10466d2a59b23aa6d5ecd5310296c8cdb6458dac)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

1 files changed, 4 insertions, 30 deletions

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 3dd7fc662859..4b23a7814713 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -595,47 +595,21 @@ i915_gem_phys_pwrite(struct drm_i915_gem_object *obj,
                      struct drm_i915_gem_pwrite *args,
                      struct drm_file *file)
 {
-        struct drm_device *dev = obj->base.dev;
         void *vaddr = obj->phys_handle->vaddr + args->offset;
         char __user *user_data = u64_to_user_ptr(args->data_ptr);
-        int ret;
 
         /* We manually control the domain here and pretend that it
          * remains coherent i.e. in the GTT domain, like shmem_pwrite.
          */
-        lockdep_assert_held(&obj->base.dev->struct_mutex);
-        ret = i915_gem_object_wait(obj,
-                                   I915_WAIT_INTERRUPTIBLE |
-                                   I915_WAIT_LOCKED |
-                                   I915_WAIT_ALL,
-                                   MAX_SCHEDULE_TIMEOUT,
-                                   to_rps_client(file));
-        if (ret)
-                return ret;
-
         intel_fb_obj_invalidate(obj, ORIGIN_CPU);
-        if (__copy_from_user_inatomic_nocache(vaddr, user_data, args->size)) {
-                unsigned long unwritten;
-
-                /* The physical object once assigned is fixed for the lifetime
-                 * of the obj, so we can safely drop the lock and continue
-                 * to access vaddr.
-                 */
-                mutex_unlock(&dev->struct_mutex);
-                unwritten = copy_from_user(vaddr, user_data, args->size);
-                mutex_lock(&dev->struct_mutex);
-                if (unwritten) {
-                        ret = -EFAULT;
-                        goto out;
-                }
-        }
+        if (copy_from_user(vaddr, user_data, args->size))
+                return -EFAULT;
 
         drm_clflush_virt_range(vaddr, args->size);
-        i915_gem_chipset_flush(to_i915(dev));
+        i915_gem_chipset_flush(to_i915(obj->base.dev));
 
-out:
         intel_fb_obj_flush(obj, false, ORIGIN_CPU);
-        return ret;
+        return 0;
 }
 
 void *i915_gem_object_alloc(struct drm_device *dev)