benchmarks/gem_wsim: Tidy manual sizeof VLA calculations

We can use offsetof for the same effect, much tidier with no dummy
locals.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

1 files changed, 6 insertions, 9 deletions

diff --git a/benchmarks/gem_wsim.c b/benchmarks/gem_wsim.c
index db19925b..a76fdbfe 100644
--- a/benchmarks/gem_wsim.c
+++ b/benchmarks/gem_wsim.c
@@ -1443,23 +1443,20 @@ set_ctx_sseu(struct ctx *ctx, uint64_t slice_mask)
 
 static size_t sizeof_load_balance(int count)
 {
-	struct i915_context_engines_load_balance *ptr;
-
-	return sizeof(*ptr) + count * sizeof(ptr->engines[0]);
+	return offsetof(struct i915_context_engines_load_balance,
+			engines[count]);
 }
 
 static size_t sizeof_param_engines(int count)
 {
-	struct i915_context_param_engines *ptr;
-
-	return sizeof(*ptr) + count * sizeof(ptr->engines[0]);
+	return offsetof(struct i915_context_param_engines,
+			engines[count]);
 }
 
 static size_t sizeof_engines_bond(int count)
 {
-	struct i915_context_engines_bond *ptr;
-
-	return sizeof(*ptr) + count * sizeof(ptr->engines[0]);
+	return offsetof(struct i915_context_engines_bond,
+			engines[count]);
 }
 
 #define alloca0(sz) ({ size_t sz__ = (sz); memset(alloca(sz__), 0, sz__); })