[PATCH buf-fix] kernel, range: fix broken mtrr_cleanup

[Shan Wei <shanwei88@gmail.com>]

From: Samuel Liao <samuelliao@tencent.com>


commit fbe06b7bae7c9cf6ab05168fce5ee93b2f4bae7c broken the mtrr_cleanup
due to return incorrect merged range. this patch remove the empty range
by swapping with the last.

Error messages:
Jun  9 14:06:18 kernel: [    0.000000] *BAD*gran_size: 64K   chunk_size: 64K         num_reg: 4      lose cover RAM: -0G
Jun  9 14:06:18 kernel: [    0.000000] *BAD*gran_size: 64K   chunk_size: 128K        num_reg: 4      lose cover RAM: -0G
Jun  9 14:06:18 kernel: [    0.000000] *BAD*gran_size: 64K   chunk_size: 256K        num_reg: 4      lose cover RAM: -0G
Jun  9 14:06:18 kernel: [    0.000000] *BAD*gran_size: 64K   chunk_size: 512K        num_reg: 4      lose cover RAM: -0G


Signed-off-by: Samuel Liao <samuelliao@tencent.com>
---
 kernel/range.c | 15 ++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/kernel/range.c b/kernel/range.c
index eb911db..b723697 100644
--- a/kernel/range.c
+++ b/kernel/range.c
@@ -48,11 +48,18 @@ int add_range_with_merge(struct range *range, int az, int nr_range,
 		final_start = min(range[i].start, start);
 		final_end = max(range[i].end, end);
 
+		if (final_start == range[i].start && final_end == range[i].end)
+			return nr_range;
+
 		/* clear it and add it back for further merge */
-		range[i].start = 0;
-		range[i].end =  0;
-		return add_range_with_merge(range, az, nr_range,
-			final_start, final_end);
+		nr_range -= 1;
+		if (i != nr_range) {
+			range[i].start = range[nr_range].start;
+			range[i].end = range[nr_range].end;
+		}
+		range[nr_range].start = 0;
+		range[nr_range].end =  0;
+		i = -1;
 	}
 
 	/* Need to add it: */
-- 
1.8.2.1