drm/i915: Implement for_each_sgt_daddr_next

Implement a way to iterate over sgt with pre-initialized
sgt_iter state.

Signed-off-by: Nirmoy Das <nirmoy.das@intel.com>
Reviewed-by: Oak Zeng <oak.zeng@intel.com>
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230926083742.14740-4-nirmoy.das@intel.com

Author: nirmoy

drivers/gpu/drm/i915/gt/intel_gtt.h

@@ -171,6 +171,9 @@ struct intel_gt;
 #define for_each_sgt_daddr(__dp, __iter, __sgt) \
 	__for_each_sgt_daddr(__dp, __iter, __sgt, I915_GTT_PAGE_SIZE)
 
+#define for_each_sgt_daddr_next(__dp, __iter) \
+	__for_each_daddr_next(__dp, __iter, I915_GTT_PAGE_SIZE)
+
 struct i915_page_table {
 	struct drm_i915_gem_object *base;
 	union {

drivers/gpu/drm/i915/i915_scatterlist.h

@@ -91,6 +91,16 @@ static inline struct scatterlist *__sg_next(struct scatterlist *sg)
 	     ((__dp) = (__iter).dma + (__iter).curr), (__iter).sgp;	\
 	     (((__iter).curr += (__step)) >= (__iter).max) ?		\
 	     (__iter) = __sgt_iter(__sg_next((__iter).sgp), true), 0 : 0)
+/**
+ * __for_each_daddr_next - iterates over the device addresses with pre-initialized iterator.
+ * @__dp:	Device address (output)
+ * @__iter:	'struct sgt_iter' (iterator state, external)
+ * @__step:	step size
+ */
+#define __for_each_daddr_next(__dp, __iter, __step)                  \
+	for (; ((__dp) = (__iter).dma + (__iter).curr), (__iter).sgp;   \
+	     (((__iter).curr += (__step)) >= (__iter).max) ?            \
+	     (__iter) = __sgt_iter(__sg_next((__iter).sgp), true), 0 : 0)
 
 /**
  * for_each_sgt_page - iterate over the pages of the given sg_table