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authorChristian König <christian.koenig@amd.com>2023-09-08 10:27:23 +0200
committerChristian König <christian.koenig@amd.com>2023-10-05 11:05:58 +0200
commitb83ce9cb4a465b8f9a3fa45561b721a9551f60e3 (patch)
tree3d460e3784fd649aa85f01ed710f361f9bc870aa /drivers/dma-buf
parentdrm/nouveau: exec: report max pushs through getparam (diff)
downloadwireguard-linux-b83ce9cb4a465b8f9a3fa45561b721a9551f60e3.tar.xz
wireguard-linux-b83ce9cb4a465b8f9a3fa45561b721a9551f60e3.zip
dma-buf: add dma_fence_timestamp helper
When a fence signals there is a very small race window where the timestamp isn't updated yet. sync_file solves this by busy waiting for the timestamp to appear, but on other ocassions didn't handled this correctly. Provide a dma_fence_timestamp() helper function for this and use it in all appropriate cases. Another alternative would be to grab the spinlock when that happens. v2 by teddy: add a wait parameter to wait for the timestamp to show up, in case the accurate timestamp is needed and/or the timestamp is not based on ktime (e.g. hw timestamp) v3 chk: drop the parameter again for unified handling Signed-off-by: Yunxiang Li <Yunxiang.Li@amd.com> Signed-off-by: Christian König <christian.koenig@amd.com> Fixes: 1774baa64f93 ("drm/scheduler: Change scheduled fence track v2") Reviewed-by: Alex Deucher <alexander.deucher@amd.com> CC: stable@vger.kernel.org Link: https://patchwork.freedesktop.org/patch/msgid/20230929104725.2358-1-christian.koenig@amd.com
Diffstat (limited to 'drivers/dma-buf')
-rw-r--r--drivers/dma-buf/dma-fence-unwrap.c13
-rw-r--r--drivers/dma-buf/sync_file.c9
2 files changed, 7 insertions, 15 deletions
diff --git a/drivers/dma-buf/dma-fence-unwrap.c b/drivers/dma-buf/dma-fence-unwrap.c
index c625bb2b5d56..628af51c81af 100644
--- a/drivers/dma-buf/dma-fence-unwrap.c
+++ b/drivers/dma-buf/dma-fence-unwrap.c
@@ -76,16 +76,11 @@ struct dma_fence *__dma_fence_unwrap_merge(unsigned int num_fences,
dma_fence_unwrap_for_each(tmp, &iter[i], fences[i]) {
if (!dma_fence_is_signaled(tmp)) {
++count;
- } else if (test_bit(DMA_FENCE_FLAG_TIMESTAMP_BIT,
- &tmp->flags)) {
- if (ktime_after(tmp->timestamp, timestamp))
- timestamp = tmp->timestamp;
} else {
- /*
- * Use the current time if the fence is
- * currently signaling.
- */
- timestamp = ktime_get();
+ ktime_t t = dma_fence_timestamp(tmp);
+
+ if (ktime_after(t, timestamp))
+ timestamp = t;
}
}
}
diff --git a/drivers/dma-buf/sync_file.c b/drivers/dma-buf/sync_file.c
index af57799c86ce..2e9a316c596a 100644
--- a/drivers/dma-buf/sync_file.c
+++ b/drivers/dma-buf/sync_file.c
@@ -268,13 +268,10 @@ static int sync_fill_fence_info(struct dma_fence *fence,
sizeof(info->driver_name));
info->status = dma_fence_get_status(fence);
- while (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags) &&
- !test_bit(DMA_FENCE_FLAG_TIMESTAMP_BIT, &fence->flags))
- cpu_relax();
info->timestamp_ns =
- test_bit(DMA_FENCE_FLAG_TIMESTAMP_BIT, &fence->flags) ?
- ktime_to_ns(fence->timestamp) :
- ktime_set(0, 0);
+ dma_fence_is_signaled(fence) ?
+ ktime_to_ns(dma_fence_timestamp(fence)) :
+ ktime_set(0, 0);
return info->status;
}