Op 05-10-2021 om 13:37 schreef Christian König:
Simplifying the code a bit.
Signed-off-by: Christian König christian.koenig@amd.com
drivers/gpu/drm/i915/gem/i915_gem_wait.c | 51 +++++------------------- 1 file changed, 9 insertions(+), 42 deletions(-)
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_wait.c b/drivers/gpu/drm/i915/gem/i915_gem_wait.c index f909aaa09d9c..a13193db1dba 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_wait.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_wait.c @@ -37,55 +37,22 @@ i915_gem_object_wait_reservation(struct dma_resv *resv, unsigned int flags, long timeout) {
- struct dma_fence *excl;
- bool prune_fences = false;
- if (flags & I915_WAIT_ALL) {
struct dma_fence **shared;unsigned int count, i;int ret;
- struct dma_resv_iter cursor;
- struct dma_fence *fence;
ret = dma_resv_get_fences(resv, &excl, &count, &shared);if (ret)return ret;for (i = 0; i < count; i++) {timeout = i915_gem_object_wait_fence(shared[i],flags, timeout);if (timeout < 0)break;dma_fence_put(shared[i]);}for (; i < count; i++)dma_fence_put(shared[i]);kfree(shared);/** If both shared fences and an exclusive fence exist,* then by construction the shared fences must be later* than the exclusive fence. If we successfully wait for* all the shared fences, we know that the exclusive fence* must all be signaled. If all the shared fences are* signaled, we can prune the array and recover the* floating references on the fences/requests.*/prune_fences = count && timeout >= 0;- } else {
excl = dma_resv_get_excl_unlocked(resv);
- dma_resv_iter_begin(&cursor, resv, flags & I915_WAIT_ALL);
- dma_resv_for_each_fence_unlocked(&cursor, fence) {
timeout = i915_gem_object_wait_fence(fence, flags, timeout);if (timeout < 0)break;
- if (excl && timeout >= 0)
timeout = i915_gem_object_wait_fence(excl, flags, timeout);- dma_fence_put(excl);
- dma_resv_iter_end(&cursor);
/* * Opportunistically prune the fences iff we know they have *all* been * signaled. */
- if (prune_fences)
- if (timeout > 0) dma_resv_prune(resv);
return timeout;
When replying to tvrtko about correctness of the conversion, I just now noticed a logic bug here, the same logic bug also affects dma_resv_wait_timeout.
long dma_resv_wait_timeout(struct dma_resv *obj, bool wait_all, bool intr, unsigned long timeout) { long ret = timeout ? timeout : 1; struct dma_resv_iter cursor; struct dma_fence *fence;
dma_resv_iter_begin(&cursor, obj, wait_all); dma_resv_for_each_fence_unlocked(&cursor, fence) {
ret = dma_fence_wait_timeout(fence, intr, ret); if (ret <= 0) { dma_resv_iter_end(&cursor); return ret; } } dma_resv_iter_end(&cursor);
return ret; }
It fails to handle the case correctly when timeout = 0, I think the original code probably did. dma_fence_wait_timeout should be called with timeout = 0 explicitly.
Fixed code for inner loop: ret = dma_fence_wait_timeout(fence, intr, timeout); if (ret <= 0) break; if (timeout) timeout = ret;
This bug also affects i915_gem_object_wait_reservation, so the whole series might need to be respinned, or at least checked, if more wait conversions are affected.
~Maarten