[RFT, PATCH v1 3/3] media: ipu3-cio2: Replace custom implementation of rotate()

[Andy Shevchenko]

rotate() is more efficient than custom implementation.
Replace the latter by the former.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
---

This should be a copy'n'paste of the algorithm with a slight difference that
it should copy by 4 or 8 bytes at a time. Nonetheless it has to be tested.
Hence, RFT. (Obviously no hurry with this, we are close to release)

 drivers/media/pci/intel/ipu3/ipu3-cio2-main.c | 59 ++-----------------
 1 file changed, 5 insertions(+), 54 deletions(-)

diff --git a/drivers/media/pci/intel/ipu3/ipu3-cio2-main.c b/drivers/media/pci/intel/ipu3/ipu3-cio2-main.c
index 8bcba168cc57..0fd6040d2f2d 100644
--- a/drivers/media/pci/intel/ipu3/ipu3-cio2-main.c
+++ b/drivers/media/pci/intel/ipu3/ipu3-cio2-main.c
@@ -21,6 +21,7 @@
 #include <linux/pfn.h>
 #include <linux/pm_runtime.h>
 #include <linux/property.h>
+#include <linux/sort.h>
 #include <linux/vmalloc.h>
 #include <media/v4l2-ctrls.h>
 #include <media/v4l2-device.h>
@@ -1877,56 +1878,6 @@ static int __maybe_unused cio2_runtime_resume(struct device *dev)
 	return 0;
 }
 
-/*
- * Helper function to advance all the elements of a circular buffer by "start"
- * positions
- */
-static void arrange(void *ptr, size_t elem_size, size_t elems, size_t start)
-{
-	struct {
-		size_t begin, end;
-	} arr[2] = {
-		{ 0, start - 1 },
-		{ start, elems - 1 },
-	};
-
-#define CHUNK_SIZE(a) ((a)->end - (a)->begin + 1)
-
-	/* Loop as long as we have out-of-place entries */
-	while (CHUNK_SIZE(&arr[0]) && CHUNK_SIZE(&arr[1])) {
-		size_t size0, i;
-
-		/*
-		 * Find the number of entries that can be arranged on this
-		 * iteration.
-		 */
-		size0 = min(CHUNK_SIZE(&arr[0]), CHUNK_SIZE(&arr[1]));
-
-		/* Swap the entries in two parts of the array. */
-		for (i = 0; i < size0; i++) {
-			u8 *d = ptr + elem_size * (arr[1].begin + i);
-			u8 *s = ptr + elem_size * (arr[0].begin + i);
-			size_t j;
-
-			for (j = 0; j < elem_size; j++)
-				swap(d[j], s[j]);
-		}
-
-		if (CHUNK_SIZE(&arr[0]) > CHUNK_SIZE(&arr[1])) {
-			/* The end of the first array remains unarranged. */
-			arr[0].begin += size0;
-		} else {
-			/*
-			 * The first array is fully arranged so we proceed
-			 * handling the next one.
-			 */
-			arr[0].begin = arr[1].begin;
-			arr[0].end = arr[1].begin + size0 - 1;
-			arr[1].begin += size0;
-		}
-	}
-}
-
 static void cio2_fbpt_rearrange(struct cio2_device *cio2, struct cio2_queue *q)
 {
 	unsigned int i, j;
@@ -1940,10 +1891,10 @@ static void cio2_fbpt_rearrange(struct cio2_device *cio2, struct cio2_queue *q)
 		return;
 
 	if (j) {
-		arrange(q->fbpt, sizeof(struct cio2_fbpt_entry) * CIO2_MAX_LOPS,
-			CIO2_MAX_BUFFERS, j);
-		arrange(q->bufs, sizeof(struct cio2_buffer *),
-			CIO2_MAX_BUFFERS, j);
+		rotate(q->fbpt, sizeof(struct cio2_fbpt_entry) * CIO2_MAX_LOPS,
+		       CIO2_MAX_BUFFERS, j, NULL);
+		rotate(q->bufs, sizeof(struct cio2_buffer *),
+		       CIO2_MAX_BUFFERS, j, NULL);
 	}
 
 	/*
-- 
2.32.0