drm/i915: Take reservation lock around i915_vma_pin.

We previously complained when ww == NULL.

This function is now only used in selftests to pin an object,
and ww locking is now fixed.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
[danvet: Resolve conflict because we don't have a set-domain refactor,
see
https://lore.kernel.org/intel-gfx/20210203090205.25818-8-chris@chris-wilson.co.uk/

The really worrying thing here is that the above patch had a change in
arguments for i915_gem_object_set_to_gtt_domain(), without any
explanation. I decided to just faithfully apply Maarten's change but
not the argument change which was in Maarten's context diff.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210323155059.628690-26-maarten.lankhorst@linux.intel.com

diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_coherency.c b/drivers/gpu/drm/i915/gem/selftests/i915_gem_coherency.c
index 1117d2a..6fe08e7 100644 (file)
--- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_coherency.c
+++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_coherency.c
@@ -200,17 +200,15 @@ static int gpu_set(struct context *ctx, unsigned long offset, u32 v)
        u32 *cs;
        int err;
 
+       vma = i915_gem_object_ggtt_pin(ctx->obj, NULL, 0, 0, 0);
+       if (IS_ERR(vma))
+               return PTR_ERR(vma);
+
        i915_gem_object_lock(ctx->obj, NULL);
        err = i915_gem_object_set_to_gtt_domain(ctx->obj, true);
        if (err)
                goto out_unlock;
 
-       vma = i915_gem_object_ggtt_pin(ctx->obj, NULL, 0, 0, 0);
-       if (IS_ERR(vma)) {
-               err = PTR_ERR(vma);
-               goto out_unlock;
-       }
-
        rq = intel_engine_create_kernel_request(ctx->engine);
        if (IS_ERR(rq)) {
                err = PTR_ERR(rq);

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 1e266c3..caa7bed 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -928,7 +928,11 @@ new_vma:
                        return ERR_PTR(ret);
        }
 
-       ret = i915_vma_pin_ww(vma, ww, size, alignment, flags | PIN_GLOBAL);
+       if (ww)
+               ret = i915_vma_pin_ww(vma, ww, size, alignment, flags | PIN_GLOBAL);
+       else
+               ret = i915_vma_pin(vma, size, alignment, flags | PIN_GLOBAL);
+
        if (ret)
                return ERR_PTR(ret);
 

diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c
index 4215714..6401299 100644 (file)
--- a/drivers/gpu/drm/i915/i915_vma.c
+++ b/drivers/gpu/drm/i915/i915_vma.c
@@ -863,9 +863,7 @@ int i915_vma_pin_ww(struct i915_vma *vma, struct i915_gem_ww_ctx *ww,
        int err;
 
 #ifdef CONFIG_PROVE_LOCKING
-       if (debug_locks && lockdep_is_held(&vma->vm->i915->drm.struct_mutex))
-               WARN_ON(!ww);
-       if (debug_locks && ww && vma->resv)
+       if (debug_locks && !WARN_ON(!ww) && vma->resv)
                assert_vma_held(vma);
 #endif
 

diff --git a/drivers/gpu/drm/i915/i915_vma.h b/drivers/gpu/drm/i915/i915_vma.h
index 6b48f5c..8df784a 100644 (file)
--- a/drivers/gpu/drm/i915/i915_vma.h
+++ b/drivers/gpu/drm/i915/i915_vma.h
@@ -246,10 +246,22 @@ i915_vma_pin_ww(struct i915_vma *vma, struct i915_gem_ww_ctx *ww,
 static inline int __must_check
 i915_vma_pin(struct i915_vma *vma, u64 size, u64 alignment, u64 flags)
 {
-#ifdef CONFIG_LOCKDEP
-       WARN_ON_ONCE(vma->resv && dma_resv_held(vma->resv));
-#endif
-       return i915_vma_pin_ww(vma, NULL, size, alignment, flags);
+       struct i915_gem_ww_ctx ww;
+       int err;
+
+       i915_gem_ww_ctx_init(&ww, true);
+retry:
+       err = i915_gem_object_lock(vma->obj, &ww);
+       if (!err)
+               err = i915_vma_pin_ww(vma, &ww, size, alignment, flags);
+       if (err == -EDEADLK) {
+               err = i915_gem_ww_ctx_backoff(&ww);
+               if (!err)
+                       goto retry;
+       }
+       i915_gem_ww_ctx_fini(&ww);
+
+       return err;
 }
 
 int i915_ggtt_pin(struct i915_vma *vma, struct i915_gem_ww_ctx *ww,