xfs: refactor cmp_two_keys routines to take advantage of cmp_int()

The net value of these functions is to determine the result of a
three-way-comparison between operands of the same type.

Simplify the code using cmp_int() to eliminate potential errors with
opencoded casts and subtractions. This also means we can change the return
value type of cmp_two_keys routines from int64_t to int and make the
interface a bit clearer.

Found by Linux Verification Center (linuxtesting.org).

Suggested-by: Darrick J. Wong <[email protected]>
Signed-off-by: Fedor Pchelkin <[email protected]>
Reviewed-by: Darrick J. Wong <[email protected]>
Signed-off-by: Carlos Maiolino <[email protected]>

1 files changed, 8 insertions, 13 deletions

diff --git a/fs/xfs/libxfs/xfs_alloc_btree.c b/fs/xfs/libxfs/xfs_alloc_btree.c
index d01807e0c4d4..f371f1b32cfb 100644
--- a/fs/xfs/libxfs/xfs_alloc_btree.c
+++ b/fs/xfs/libxfs/xfs_alloc_btree.c
@@ -213,7 +213,7 @@ xfs_cntbt_cmp_key_with_cur(
 	return (int64_t)be32_to_cpu(kp->ar_startblock) - rec->ar_startblock;
 }
 
-STATIC int64_t
+STATIC int
 xfs_bnobt_cmp_two_keys(
 	struct xfs_btree_cur		*cur,
 	const union xfs_btree_key	*k1,
@@ -222,29 +222,24 @@ xfs_bnobt_cmp_two_keys(
 {
 	ASSERT(!mask || mask->alloc.ar_startblock);
 
-	return (int64_t)be32_to_cpu(k1->alloc.ar_startblock) -
-			be32_to_cpu(k2->alloc.ar_startblock);
+	return cmp_int(be32_to_cpu(k1->alloc.ar_startblock),
+		       be32_to_cpu(k2->alloc.ar_startblock));
 }
 
-STATIC int64_t
+STATIC int
 xfs_cntbt_cmp_two_keys(
 	struct xfs_btree_cur		*cur,
 	const union xfs_btree_key	*k1,
 	const union xfs_btree_key	*k2,
 	const union xfs_btree_key	*mask)
 {
-	int64_t				diff;
-
 	ASSERT(!mask || (mask->alloc.ar_blockcount &&
 			 mask->alloc.ar_startblock));
 
-	diff =  be32_to_cpu(k1->alloc.ar_blockcount) -
-		be32_to_cpu(k2->alloc.ar_blockcount);
-	if (diff)
-		return diff;
-
-	return  be32_to_cpu(k1->alloc.ar_startblock) -
-		be32_to_cpu(k2->alloc.ar_startblock);
+	return cmp_int(be32_to_cpu(k1->alloc.ar_blockcount),
+		       be32_to_cpu(k2->alloc.ar_blockcount)) ?:
+	       cmp_int(be32_to_cpu(k1->alloc.ar_startblock),
+		       be32_to_cpu(k2->alloc.ar_startblock));
 }
 
 static xfs_failaddr_t