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authorChristian König <ckoenig.leichtzumerken@gmail.com>2024-05-29 10:43:22 +0200
committerChristian König <christian.koenig@amd.com>2024-05-31 10:12:52 +0200
commitc9402efe492bb46ccbf94fedc4783eb8f8747567 (patch)
tree9e13353300e31e6340b00c6a11cdae66ab57f762
parentdrm/ci: validate drm/msm XML register files against schema (diff)
downloadlinux-c9402efe492bb46ccbf94fedc4783eb8f8747567.tar.xz
linux-c9402efe492bb46ccbf94fedc4783eb8f8747567.zip
dma-buf: add a warning when drv try to reserve 0 fence slots
When dma_resv_reserve_fences() is called with num_fences=0 it usually means that a driver or other component messed up its calculation how many fences are needed. Warn in that situation. When no fence are needed the function shouldn't be called in the first place. Signed-off-by: Christian König <christian.koenig@amd.com> Link: https://patchwork.freedesktop.org/patch/msgid/20240529084322.2284-1-christian.koenig@amd.com Reviewed-by: Matthew Auld <matthew.auld@intel.com>
-rw-r--r--drivers/dma-buf/dma-resv.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/drivers/dma-buf/dma-resv.c b/drivers/dma-buf/dma-resv.c
index e2869fb31140..5f8d010516f0 100644
--- a/drivers/dma-buf/dma-resv.c
+++ b/drivers/dma-buf/dma-resv.c
@@ -186,6 +186,13 @@ int dma_resv_reserve_fences(struct dma_resv *obj, unsigned int num_fences)
dma_resv_assert_held(obj);
+ /* Driver and component code should never call this function with
+ * num_fences=0. If they do it usually points to bugs when calculating
+ * the number of needed fences dynamically.
+ */
+ if (WARN_ON(!num_fences))
+ return -EINVAL;
+
old = dma_resv_fences_list(obj);
if (old && old->max_fences) {
if ((old->num_fences + num_fences) <= old->max_fences)