[Intel-gfx] [PATCH 7/7] drm/i915: Trim unused workaround list entries

[Tvrtko Ursulin]

From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>

The new workaround list allocator grows the list in chunks so will end up
with some unused space. Trim it when the initialization phase is done to
free up a tiny bit of slab.

v2:
 * Simplify with kmemdup. (Chris Wilson)

v3:
 * Refactor for __size removal.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk> # v2
---
 drivers/gpu/drm/i915/intel_workarounds.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_workarounds.c b/drivers/gpu/drm/i915/intel_workarounds.c
index 53a6d6327020..5917b760a3ae 100644
--- a/drivers/gpu/drm/i915/intel_workarounds.c
+++ b/drivers/gpu/drm/i915/intel_workarounds.c
@@ -53,8 +53,22 @@ static void wa_init_start(struct i915_wa_list *wal, const char *name)
 	wal->name = name;
 }
 
+#define WA_LIST_CHUNK (1 << 4)
+
 static void wa_init_finish(struct i915_wa_list *wal)
 {
+	/* Trim unused entries. */
+	if (!IS_ALIGNED(wal->count, WA_LIST_CHUNK)) {
+		struct i915_wa *list = kmemdup(wal->list,
+					       wal->count * sizeof(*list),
+					       GFP_KERNEL);
+
+		if (list) {
+			kfree(wal->list);
+			wal->list = list;
+		}
+	}
+
 	if (!wal->count)
 		return;
 
@@ -66,7 +80,7 @@ static void _wa_add(struct i915_wa_list *wal, const struct i915_wa *wa)
 {
 	unsigned int addr = i915_mmio_reg_offset(wa->reg);
 	unsigned int start = 0, end = wal->count;
-	const unsigned int grow = 1 << 4;
+	const unsigned int grow = WA_LIST_CHUNK;
 	struct i915_wa *wa_;
 
 	GEM_BUG_ON(!is_power_of_2(grow));
-- 
2.19.1