[Intel-gfx] [PATCH] drm/i915: Disallow preallocation of requests
Daniel Vetter
daniel at ffwll.ch
Thu Sep 27 13:46:57 CEST 2012
On Thu, Sep 27, 2012 at 10:39:53AM +0300, Jani Nikula wrote:
> On Wed, 26 Sep 2012, Chris Wilson <chris at chris-wilson.co.uk> wrote:
> > The intention was to allow the caller to avoid a failure to queue a
> > request having already written commands to the ring. However, this is a
> > moot point as the i915_add_request() can fail for other reasons than a
> > mere allocation failure and those failure cases are more likely than
> > ENOMEM. So the overlay code already had to handle i915_add_request()
> > failures, and due to
> >
> > commit 3bb73aba1ed5198a2c1dfaac4f3c95459930d84a
> > Author: Chris Wilson <chris at chris-wilson.co.uk>
> > Date: Fri Jul 20 12:40:59 2012 +0100
> >
> > drm/i915: Allow late allocation of request for i915_add_request()
> >
> > the error handling code in intel_overlay.c was subject to causing
> > double-frees, as found by coverity.
> >
> > Rather than further complicate i915_add_request() and callers, realise
> > the battle is lost and adapt intel_overlay.c to take advantage of the
> > late allocation of requests.
> >
> > v2: Handle callers passing in a NULL seqno.
> > v3: Ditto. This time for sure.
> >
> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> > ---
> > drivers/gpu/drm/i915/i915_drv.h | 2 +-
> > drivers/gpu/drm/i915/i915_gem.c | 15 +++----
> > drivers/gpu/drm/i915/intel_overlay.c | 72 +++++++---------------------------
> > 3 files changed, 24 insertions(+), 65 deletions(-)
>
> Looks good, and I also like the diffstat.
>
> Reviewed-by: Jani Nikula <jani.nikula at intel.com>
Picked up for -fixes, thanks for the patch.
-Daniel
>
> >
> > diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> > index dddc3dc..d8d4736 100644
> > --- a/drivers/gpu/drm/i915/i915_drv.h
> > +++ b/drivers/gpu/drm/i915/i915_drv.h
> > @@ -1468,7 +1468,7 @@ int __must_check i915_gpu_idle(struct drm_device *dev);
> > int __must_check i915_gem_idle(struct drm_device *dev);
> > int i915_add_request(struct intel_ring_buffer *ring,
> > struct drm_file *file,
> > - struct drm_i915_gem_request *request);
> > + u32 *seqno);
> > int __must_check i915_wait_seqno(struct intel_ring_buffer *ring,
> > uint32_t seqno);
> > int i915_gem_fault(struct vm_area_struct *vma, struct vm_fault *vmf);
> > diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> > index b2effab..014b95e 100644
> > --- a/drivers/gpu/drm/i915/i915_gem.c
> > +++ b/drivers/gpu/drm/i915/i915_gem.c
> > @@ -2087,11 +2087,12 @@ i915_gem_next_request_seqno(struct intel_ring_buffer *ring)
> > int
> > i915_add_request(struct intel_ring_buffer *ring,
> > struct drm_file *file,
> > - struct drm_i915_gem_request *request)
> > + u32 *out_seqno)
> > {
> > drm_i915_private_t *dev_priv = ring->dev->dev_private;
> > - uint32_t seqno;
> > + struct drm_i915_gem_request *request;
> > u32 request_ring_position;
> > + u32 seqno;
> > int was_empty;
> > int ret;
> >
> > @@ -2106,11 +2107,9 @@ i915_add_request(struct intel_ring_buffer *ring,
> > if (ret)
> > return ret;
> >
> > - if (request == NULL) {
> > - request = kmalloc(sizeof(*request), GFP_KERNEL);
> > - if (request == NULL)
> > - return -ENOMEM;
> > - }
> > + request = kmalloc(sizeof(*request), GFP_KERNEL);
> > + if (request == NULL)
> > + return -ENOMEM;
> >
> > seqno = i915_gem_next_request_seqno(ring);
> >
> > @@ -2162,6 +2161,8 @@ i915_add_request(struct intel_ring_buffer *ring,
> > }
> > }
> >
> > + if (out_seqno)
> > + *out_seqno = seqno;
> > return 0;
> > }
> >
> > diff --git a/drivers/gpu/drm/i915/intel_overlay.c b/drivers/gpu/drm/i915/intel_overlay.c
> > index 2fa20a4..ebcbf48 100644
> > --- a/drivers/gpu/drm/i915/intel_overlay.c
> > +++ b/drivers/gpu/drm/i915/intel_overlay.c
> > @@ -210,7 +210,6 @@ static void intel_overlay_unmap_regs(struct intel_overlay *overlay,
> > }
> >
> > static int intel_overlay_do_wait_request(struct intel_overlay *overlay,
> > - struct drm_i915_gem_request *request,
> > void (*tail)(struct intel_overlay *))
> > {
> > struct drm_device *dev = overlay->dev;
> > @@ -219,12 +218,10 @@ static int intel_overlay_do_wait_request(struct intel_overlay *overlay,
> > int ret;
> >
> > BUG_ON(overlay->last_flip_req);
> > - ret = i915_add_request(ring, NULL, request);
> > - if (ret) {
> > - kfree(request);
> > - return ret;
> > - }
> > - overlay->last_flip_req = request->seqno;
> > + ret = i915_add_request(ring, NULL, &overlay->last_flip_req);
> > + if (ret)
> > + return ret;
> > +
> > overlay->flip_tail = tail;
> > ret = i915_wait_seqno(ring, overlay->last_flip_req);
> > if (ret)
> > @@ -241,7 +238,6 @@ static int intel_overlay_on(struct intel_overlay *overlay)
> > struct drm_device *dev = overlay->dev;
> > struct drm_i915_private *dev_priv = dev->dev_private;
> > struct intel_ring_buffer *ring = &dev_priv->ring[RCS];
> > - struct drm_i915_gem_request *request;
> > int ret;
> >
> > BUG_ON(overlay->active);
> > @@ -249,17 +245,9 @@ static int intel_overlay_on(struct intel_overlay *overlay)
> >
> > WARN_ON(IS_I830(dev) && !(dev_priv->quirks & QUIRK_PIPEA_FORCE));
> >
> > - request = kzalloc(sizeof(*request), GFP_KERNEL);
> > - if (request == NULL) {
> > - ret = -ENOMEM;
> > - goto out;
> > - }
> > -
> > ret = intel_ring_begin(ring, 4);
> > - if (ret) {
> > - kfree(request);
> > - goto out;
> > - }
> > + if (ret)
> > + return ret;
> >
> > intel_ring_emit(ring, MI_OVERLAY_FLIP | MI_OVERLAY_ON);
> > intel_ring_emit(ring, overlay->flip_addr | OFC_UPDATE);
> > @@ -267,9 +255,7 @@ static int intel_overlay_on(struct intel_overlay *overlay)
> > intel_ring_emit(ring, MI_NOOP);
> > intel_ring_advance(ring);
> >
> > - ret = intel_overlay_do_wait_request(overlay, request, NULL);
> > -out:
> > - return ret;
> > + return intel_overlay_do_wait_request(overlay, NULL);
> > }
> >
> > /* overlay needs to be enabled in OCMD reg */
> > @@ -279,17 +265,12 @@ static int intel_overlay_continue(struct intel_overlay *overlay,
> > struct drm_device *dev = overlay->dev;
> > drm_i915_private_t *dev_priv = dev->dev_private;
> > struct intel_ring_buffer *ring = &dev_priv->ring[RCS];
> > - struct drm_i915_gem_request *request;
> > u32 flip_addr = overlay->flip_addr;
> > u32 tmp;
> > int ret;
> >
> > BUG_ON(!overlay->active);
> >
> > - request = kzalloc(sizeof(*request), GFP_KERNEL);
> > - if (request == NULL)
> > - return -ENOMEM;
> > -
> > if (load_polyphase_filter)
> > flip_addr |= OFC_UPDATE;
> >
> > @@ -299,22 +280,14 @@ static int intel_overlay_continue(struct intel_overlay *overlay,
> > DRM_DEBUG("overlay underrun, DOVSTA: %x\n", tmp);
> >
> > ret = intel_ring_begin(ring, 2);
> > - if (ret) {
> > - kfree(request);
> > + if (ret)
> > return ret;
> > - }
> > +
> > intel_ring_emit(ring, MI_OVERLAY_FLIP | MI_OVERLAY_CONTINUE);
> > intel_ring_emit(ring, flip_addr);
> > intel_ring_advance(ring);
> >
> > - ret = i915_add_request(ring, NULL, request);
> > - if (ret) {
> > - kfree(request);
> > - return ret;
> > - }
> > -
> > - overlay->last_flip_req = request->seqno;
> > - return 0;
> > + return i915_add_request(ring, NULL, &overlay->last_flip_req);
> > }
> >
> > static void intel_overlay_release_old_vid_tail(struct intel_overlay *overlay)
> > @@ -350,15 +323,10 @@ static int intel_overlay_off(struct intel_overlay *overlay)
> > struct drm_i915_private *dev_priv = dev->dev_private;
> > struct intel_ring_buffer *ring = &dev_priv->ring[RCS];
> > u32 flip_addr = overlay->flip_addr;
> > - struct drm_i915_gem_request *request;
> > int ret;
> >
> > BUG_ON(!overlay->active);
> >
> > - request = kzalloc(sizeof(*request), GFP_KERNEL);
> > - if (request == NULL)
> > - return -ENOMEM;
> > -
> > /* According to intel docs the overlay hw may hang (when switching
> > * off) without loading the filter coeffs. It is however unclear whether
> > * this applies to the disabling of the overlay or to the switching off
> > @@ -366,10 +334,9 @@ static int intel_overlay_off(struct intel_overlay *overlay)
> > flip_addr |= OFC_UPDATE;
> >
> > ret = intel_ring_begin(ring, 6);
> > - if (ret) {
> > - kfree(request);
> > + if (ret)
> > return ret;
> > - }
> > +
> > /* wait for overlay to go idle */
> > intel_ring_emit(ring, MI_OVERLAY_FLIP | MI_OVERLAY_CONTINUE);
> > intel_ring_emit(ring, flip_addr);
> > @@ -380,8 +347,7 @@ static int intel_overlay_off(struct intel_overlay *overlay)
> > intel_ring_emit(ring, MI_WAIT_FOR_EVENT | MI_WAIT_FOR_OVERLAY_FLIP);
> > intel_ring_advance(ring);
> >
> > - return intel_overlay_do_wait_request(overlay, request,
> > - intel_overlay_off_tail);
> > + return intel_overlay_do_wait_request(overlay, intel_overlay_off_tail);
> > }
> >
> > /* recover from an interruption due to a signal
> > @@ -426,24 +392,16 @@ static int intel_overlay_release_old_vid(struct intel_overlay *overlay)
> > return 0;
> >
> > if (I915_READ(ISR) & I915_OVERLAY_PLANE_FLIP_PENDING_INTERRUPT) {
> > - struct drm_i915_gem_request *request;
> > -
> > /* synchronous slowpath */
> > - request = kzalloc(sizeof(*request), GFP_KERNEL);
> > - if (request == NULL)
> > - return -ENOMEM;
> > -
> > ret = intel_ring_begin(ring, 2);
> > - if (ret) {
> > - kfree(request);
> > + if (ret)
> > return ret;
> > - }
> >
> > intel_ring_emit(ring, MI_WAIT_FOR_EVENT | MI_WAIT_FOR_OVERLAY_FLIP);
> > intel_ring_emit(ring, MI_NOOP);
> > intel_ring_advance(ring);
> >
> > - ret = intel_overlay_do_wait_request(overlay, request,
> > + ret = intel_overlay_do_wait_request(overlay,
> > intel_overlay_release_old_vid_tail);
> > if (ret)
> > return ret;
> > --
> > 1.7.10.4
> >
> > _______________________________________________
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> > Intel-gfx at lists.freedesktop.org
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--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
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