[Intel-gfx] [PATCH 3/5] drm/i915: Implement __for_each_sgt_daddr_next

[Nirmoy Das <nirmoy.das@intel.com>]

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

Signed-off-by: Nirmoy Das <nirmoy.das@intel.com>
---
 drivers/gpu/drm/i915/i915_scatterlist.h | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_scatterlist.h b/drivers/gpu/drm/i915/i915_scatterlist.h
index 5a10c1a31183..6cf8a298849f 100644
--- a/drivers/gpu/drm/i915/i915_scatterlist.h
+++ b/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
-- 
2.41.0