[PATCH] drm/i915: Move fd_install after last use of fence

Rob Clark
2023-02-03T16:50:02Z

From: Rob Clark <robdclark@chromium.org>

Because eb_composite_fence_create() drops the fence_array reference
after creation of the sync_file, only the sync_file holds a ref to the
fence. But fd_install() makes that reference visable to userspace, so
it must be the last thing we do with the fence.

Signed-off-by: Rob Clark <robdclark@chromium.org>
---
drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
index f266b68cf012..0f2e056c02dd 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
@@ -3476,38 +3476,38 @@ i915_gem_do_execbuffer(struct drm_device *dev,

err_request:
eb_requests_get(&eb);
err = eb_requests_add(&eb, err);

if (eb.fences)
signal_fence_array(&eb, eb.composite_fence ?
eb.composite_fence :
&eb.requests[0]->fence);

+ if (unlikely(eb.gem_context->syncobj)) {
+ drm_syncobj_replace_fence(eb.gem_context->syncobj,
+ eb.composite_fence ?
+ eb.composite_fence :
+ &eb.requests[0]->fence);
+ }
+
if (out_fence) {
if (err == 0) {
fd_install(out_fence_fd, out_fence->file);
args->rsvd2 &= GENMASK_ULL(31, 0); /* keep in-fence */
args->rsvd2 |= (u64)out_fence_fd << 32;
out_fence_fd = -1;
} else {
fput(out_fence->file);
}
}

- if (unlikely(eb.gem_context->syncobj)) {
- drm_syncobj_replace_fence(eb.gem_context->syncobj,
- eb.composite_fence ?
- eb.composite_fence :
- &eb.requests[0]->fence);
- }
-
if (!out_fence && eb.composite_fence)
dma_fence_put(eb.composite_fence);

eb_requests_put(&eb);

err_vma:
eb_release_vmas(&eb, true);
WARN_ON(err == -EDEADLK);
i915_gem_ww_ctx_fini(&eb.ww);

--
2.38.1