"ring->space" is unsigned so it's never less than zero.
Signed-off-by: Dan Carpenter <error27@xxxxxxxxx>
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 51e9c9e..a331898 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -208,9 +208,10 @@ static int init_ring_common(struct drm_device *dev,
else {
ring->head = ring->get_head(dev, ring);
ring->tail = ring->get_tail(dev, ring);
- ring->space = ring->head - (ring->tail + 8);
- if (ring->space < 0)
- ring->space += ring->size;
+ if (ring->head >= ring->tail + 8)
+ ring->space = ring->head - (ring->tail + 8);
+ else
+ ring->space = ring->head - (ring->tail + 8) + ring->size;
}
return 0;
}
@@ -666,9 +667,10 @@ int intel_init_ring_buffer(struct drm_device *dev,
else {
ring->head = ring->get_head(dev, ring);
ring->tail = ring->get_tail(dev, ring);
- ring->space = ring->head - (ring->tail + 8);
- if (ring->space < 0)
- ring->space += ring->size;
+ if (ring->head >= ring->tail + 8)
+ ring->space = ring->head - (ring->tail + 8);
+ else
+ ring->space = ring->head - (ring->tail + 8) + ring->size;
}
INIT_LIST_HEAD(&ring->active_list);
INIT_LIST_HEAD(&ring->request_list);
@@ -735,9 +737,10 @@ int intel_wait_ring_buffer(struct drm_device *dev,
end = jiffies + 3 * HZ;
do {
ring->head = ring->get_head(dev, ring);
- ring->space = ring->head - (ring->tail + 8);
- if (ring->space < 0)
- ring->space += ring->size;
+ if (ring->head >= ring->tail + 8)
+ ring->space = ring->head - (ring->tail + 8);
+ else
+ ring->space = ring->head - (ring->tail + 8) + ring->size;
if (ring->space >= n) {
trace_i915_ring_wait_end (dev);
return 0;
diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index 44af317..707f32f 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -109,9 +109,10 @@ void i915_kernel_lost_context(struct drm_device * dev)
ring->head = I915_READ(PRB0_HEAD) & HEAD_ADDR;
ring->tail = I915_READ(PRB0_TAIL) & TAIL_ADDR;
- ring->space = ring->head - (ring->tail + 8);
- if (ring->space < 0)
- ring->space += ring->size;
+ if (ring->head >= ring->tail + 8)
+ ring->space = ring->head - (ring->tail + 8);
+ else
+ ring->space = ring->head - (ring->tail + 8) + ring->size;
if (!dev->primary->master)
return;
--
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