6.1-stable review patch. If anyone has any objections, please let me know.
------------------
From: Christian König <christian.koenig@xxxxxxx>
commit 95ba893c9f4feb836ddce627efd0bb6af6667031 upstream.
It's valid to add the same fence multiple times to a dma-resv object and
we shouldn't need one extra slot for each.
Signed-off-by: Christian König <christian.koenig@xxxxxxx>
Reviewed-by: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx>
Fixes: a3f7c10a269d5 ("dma-buf/dma-resv: check if the new fence is really later")
Cc: stable@xxxxxxxxxxxxxxx # v5.19+
Link: https://patchwork.freedesktop.org/patch/msgid/20231115093035.1889-1-christian.koenig@xxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/dma-buf/dma-resv.c | 2 +-
include/linux/dma-fence.h | 15 +++++++++++++++
2 files changed, 16 insertions(+), 1 deletion(-)
--- a/drivers/dma-buf/dma-resv.c
+++ b/drivers/dma-buf/dma-resv.c
@@ -296,7 +296,7 @@ void dma_resv_add_fence(struct dma_resv
dma_resv_list_entry(fobj, i, obj, &old, &old_usage);
if ((old->context == fence->context && old_usage >= usage &&
- dma_fence_is_later(fence, old)) ||
+ dma_fence_is_later_or_same(fence, old)) ||
dma_fence_is_signaled(old)) {
dma_resv_list_set(fobj, i, fence, usage);
dma_fence_put(old);
--- a/include/linux/dma-fence.h
+++ b/include/linux/dma-fence.h
@@ -479,6 +479,21 @@ static inline bool dma_fence_is_later(st
}
/**
+ * dma_fence_is_later_or_same - return true if f1 is later or same as f2
+ * @f1: the first fence from the same context
+ * @f2: the second fence from the same context
+ *
+ * Returns true if f1 is chronologically later than f2 or the same fence. Both
+ * fences must be from the same context, since a seqno is not re-used across
+ * contexts.
+ */
+static inline bool dma_fence_is_later_or_same(struct dma_fence *f1,
+ struct dma_fence *f2)
+{
+ return f1 == f2 || dma_fence_is_later(f1, f2);
+}
+
+/**
* dma_fence_later - return the chronologically later fence
* @f1: the first fence from the same context
* @f2: the second fence from the same context
