[PATCH V2 02/12] badblocks: factor out a helper try_adjacent_combine

[Zheng Qixing]

From: Li Nan <linan...@huawei.com>

Factor out try_adjacent_combine(), and it will be used in the later patch.

Signed-off-by: Li Nan <linan...@huawei.com>
Reviewed-by: Yu Kuai <yuku...@huawei.com>
---
 block/badblocks.c | 40 ++++++++++++++++++++++++++--------------
 1 file changed, 26 insertions(+), 14 deletions(-)

diff --git a/block/badblocks.c b/block/badblocks.c
index bcee057efc47..f069c93e986d 100644
--- a/block/badblocks.c
+++ b/block/badblocks.c
@@ -855,6 +855,31 @@ static void badblocks_update_acked(struct badblocks *bb)
                bb->unacked_exist = 0;
 }
 
+/*
+ * Return 'true' if the range indicated by 'bad' is exactly backward
+ * overlapped with the bad range (from bad table) indexed by 'behind'.
+ */
+static bool try_adjacent_combine(struct badblocks *bb, int prev)
+{
+       u64 *p = bb->page;
+
+       if (prev >= 0 && (prev + 1) < bb->count &&
+           BB_END(p[prev]) == BB_OFFSET(p[prev + 1]) &&
+           (BB_LEN(p[prev]) + BB_LEN(p[prev + 1])) <= BB_MAX_LEN &&
+           BB_ACK(p[prev]) == BB_ACK(p[prev + 1])) {
+               p[prev] = BB_MAKE(BB_OFFSET(p[prev]),
+                                 BB_LEN(p[prev]) + BB_LEN(p[prev + 1]),
+                                 BB_ACK(p[prev]));
+
+               if ((prev + 2) < bb->count)
+                       memmove(p + prev + 1, p + prev + 2,
+                               (bb->count -  (prev + 2)) * 8);
+               bb->count--;
+               return true;
+       }
+       return false;
+}
+
 /* Do exact work to set bad block range into the bad block table */
 static int _badblocks_set(struct badblocks *bb, sector_t s, int sectors,
                          int acknowledged)
@@ -1022,20 +1047,7 @@ static int _badblocks_set(struct badblocks *bb, sector_t 
s, int sectors,
         * merged. (prev < 0) condition is not handled here,
         * because it's already complicated enough.
         */
-       if (prev >= 0 &&
-           (prev + 1) < bb->count &&
-           BB_END(p[prev]) == BB_OFFSET(p[prev + 1]) &&
-           (BB_LEN(p[prev]) + BB_LEN(p[prev + 1])) <= BB_MAX_LEN &&
-           BB_ACK(p[prev]) == BB_ACK(p[prev + 1])) {
-               p[prev] = BB_MAKE(BB_OFFSET(p[prev]),
-                                 BB_LEN(p[prev]) + BB_LEN(p[prev + 1]),
-                                 BB_ACK(p[prev]));
-
-               if ((prev + 2) < bb->count)
-                       memmove(p + prev + 1, p + prev + 2,
-                               (bb->count -  (prev + 2)) * 8);
-               bb->count--;
-       }
+       try_adjacent_combine(bb, prev);
 
        if (space_desired && !badblocks_full(bb)) {
                s = orig_start;
-- 
2.39.2