[Intel-gfx] [PATCH] drm/i915: Disallow preallocation of requests
Chris Wilson
chris at chris-wilson.co.uk
Wed Sep 26 14:44:10 CEST 2012
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
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 | 14 +++----
drivers/gpu/drm/i915/intel_overlay.c | 72 +++++++---------------------------
3 files changed, 23 insertions(+), 65 deletions(-)
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..489d32d 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 +2161,7 @@ i915_add_request(struct intel_ring_buffer *ring,
}
}
+ *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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