On Tue, Feb 28, 2017 at 04:22:33PM +0000, Chris Wilson wrote: > Reintroduce a lock around tiling vs framebuffer creation to prevent > modification of the obj->tiling_and_stride whilst the framebuffer is > being created. Rather than use struct_mutex once again, use the > per-object lock - this will also be required in future to prevent > changing the tiling whilst submitting rendering. > > Fixes: 24dbf51a5517 ("drm/i915: struct_mutex is not required for allocating > the framebuffer") > Signed-off-by: Chris Wilson <ch...@chris-wilson.co.uk> > Cc: Ville Syrjälä <ville.syrj...@linux.intel.com> > --- > drivers/gpu/drm/i915/i915_gem_object.h | 18 +++++++++++++++++- > drivers/gpu/drm/i915/i915_gem_shrinker.c | 2 +- > drivers/gpu/drm/i915/i915_gem_tiling.c | 9 ++++++++- > drivers/gpu/drm/i915/intel_display.c | 25 ++++++++++++++++--------- > 4 files changed, 42 insertions(+), 12 deletions(-) > > diff --git a/drivers/gpu/drm/i915/i915_gem_object.h > b/drivers/gpu/drm/i915/i915_gem_object.h > index ad1bc0b1a0c2..8c02c8ec2a3b 100644 > --- a/drivers/gpu/drm/i915/i915_gem_object.h > +++ b/drivers/gpu/drm/i915/i915_gem_object.h > @@ -169,7 +169,7 @@ struct drm_i915_gem_object { > struct reservation_object *resv; > > /** References from framebuffers, locks out tiling changes. */ > - atomic_t framebuffer_references; > + unsigned int framebuffer_references; > > /** Record of address bit 17 of each page at last unbind. */ > unsigned long *bit_17; > @@ -263,6 +263,16 @@ extern void drm_gem_object_unreference(struct > drm_gem_object *); > __deprecated > extern void drm_gem_object_unreference_unlocked(struct drm_gem_object *); > > +static inline void i915_gem_object_lock(struct drm_i915_gem_object *obj) > +{ > + reservation_object_lock(obj->resv, NULL); > +} > + > +static inline void i915_gem_object_unlock(struct drm_i915_gem_object *obj) > +{ > + reservation_object_unlock(obj->resv); > +} > + > static inline bool > i915_gem_object_has_struct_page(const struct drm_i915_gem_object *obj) > { > @@ -303,6 +313,12 @@ i915_gem_object_clear_active_reference(struct > drm_i915_gem_object *obj) > > void __i915_gem_object_release_unless_active(struct drm_i915_gem_object > *obj); > > +static inline bool > +i915_gem_object_is_framebuffer(const struct drm_i915_gem_object *obj) > +{ > + return READ_ONCE(obj->framebuffer_references); > +} > + > static inline unsigned int > i915_gem_object_get_tiling(struct drm_i915_gem_object *obj) > { > diff --git a/drivers/gpu/drm/i915/i915_gem_shrinker.c > b/drivers/gpu/drm/i915/i915_gem_shrinker.c > index 7e3bb48e043e..630697001b38 100644 > --- a/drivers/gpu/drm/i915/i915_gem_shrinker.c > +++ b/drivers/gpu/drm/i915/i915_gem_shrinker.c > @@ -210,7 +210,7 @@ i915_gem_shrink(struct drm_i915_private *dev_priv, > > if (!(flags & I915_SHRINK_ACTIVE) && > (i915_gem_object_is_active(obj) || > - atomic_read(&obj->framebuffer_references))) > + i915_gem_object_is_framebuffer(obj))) > continue; > > if (!can_release_pages(obj)) > diff --git a/drivers/gpu/drm/i915/i915_gem_tiling.c > b/drivers/gpu/drm/i915/i915_gem_tiling.c > index c1d669e32f41..ad5e05f6b836 100644 > --- a/drivers/gpu/drm/i915/i915_gem_tiling.c > +++ b/drivers/gpu/drm/i915/i915_gem_tiling.c > @@ -238,7 +238,7 @@ i915_gem_object_set_tiling(struct drm_i915_gem_object > *obj, > if ((tiling | stride) == obj->tiling_and_stride) > return 0; > > - if (atomic_read(&obj->framebuffer_references)) > + if (i915_gem_object_is_framebuffer(obj)) > return -EBUSY; > > /* We need to rebind the object if its current allocation > @@ -258,6 +258,12 @@ i915_gem_object_set_tiling(struct drm_i915_gem_object > *obj, > if (err) > return err; > > + i915_gem_object_lock(obj); > + if (i915_gem_object_is_framebuffer(obj)) { > + i915_gem_object_unlock(obj); > + return -EBUSY; > + } > + > /* If the memory has unknown (i.e. varying) swizzling, we pin the > * pages to prevent them being swapped out and causing corruption > * due to the change in swizzling. > @@ -294,6 +300,7 @@ i915_gem_object_set_tiling(struct drm_i915_gem_object > *obj, > } > > obj->tiling_and_stride = tiling | stride; > + i915_gem_object_unlock(obj); > > /* Force the fence to be reacquired for GTT access */ > i915_gem_release_mmap(obj); > diff --git a/drivers/gpu/drm/i915/intel_display.c > b/drivers/gpu/drm/i915/intel_display.c > index 77936ddd860a..62a1e628e399 100644 > --- a/drivers/gpu/drm/i915/intel_display.c > +++ b/drivers/gpu/drm/i915/intel_display.c > @@ -14255,7 +14255,10 @@ static void intel_user_framebuffer_destroy(struct > drm_framebuffer *fb) > > drm_framebuffer_cleanup(fb); > > - WARN_ON(atomic_dec_return(&intel_fb->obj->framebuffer_references) < 0); > + i915_gem_object_lock(intel_fb->obj); > + WARN_ON(!intel_fb->obj->framebuffer_references--); > + i915_gem_object_unlock(intel_fb->obj); > + > i915_gem_object_put(intel_fb->obj); > > kfree(intel_fb); > @@ -14332,12 +14335,16 @@ static int intel_framebuffer_init(struct > intel_framebuffer *intel_fb, > struct drm_mode_fb_cmd2 *mode_cmd) > { > struct drm_i915_private *dev_priv = to_i915(obj->base.dev); > - unsigned int tiling = i915_gem_object_get_tiling(obj); > - u32 pitch_limit, stride_alignment; > struct drm_format_name_buf format_name; > + u32 pitch_limit, stride_alignment; > + unsigned int tiling, stride; > int ret = -EINVAL; > > - atomic_inc(&obj->framebuffer_references); > + i915_gem_object_lock(obj); > + obj->framebuffer_references++; > + tiling = i915_gem_object_get_tiling(obj); > + stride = i915_gem_object_get_stride(obj); > + i915_gem_object_unlock(obj);
I can't say I'm really up to date on the object locking stuff, but from the display POV this looks all right to me. So good enough for me :) Reviewed-by: Ville Syrjälä <ville.syrj...@linux.intel.com> > > if (mode_cmd->flags & DRM_MODE_FB_MODIFIERS) { > /* > @@ -14409,11 +14416,9 @@ static int intel_framebuffer_init(struct > intel_framebuffer *intel_fb, > * If there's a fence, enforce that > * the fb pitch and fence stride match. > */ > - if (tiling != I915_TILING_NONE && > - mode_cmd->pitches[0] != i915_gem_object_get_stride(obj)) { > + if (tiling != I915_TILING_NONE && mode_cmd->pitches[0] != stride) { > DRM_DEBUG("pitch (%d) must match tiling stride (%d)\n", > - mode_cmd->pitches[0], > - i915_gem_object_get_stride(obj)); > + mode_cmd->pitches[0], stride); > goto err; > } > > @@ -14494,7 +14499,9 @@ static int intel_framebuffer_init(struct > intel_framebuffer *intel_fb, > return 0; > > err: > - atomic_dec(&obj->framebuffer_references); > + i915_gem_object_lock(obj); > + obj->framebuffer_references--; > + i915_gem_object_unlock(obj); > return ret; > } > > -- > 2.11.0 -- Ville Syrjälä Intel OTC _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx