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 <djwong@kernel.org>
Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Carlos Maiolino <cem@kernel.org>

9 files changed, 48 insertions, 84 deletions

diff --git a/fs/xfs/libxfs/xfs_alloc_btree.c b/fs/xfs/libxfs/xfs_alloc_btree.c
index d01807e0c4d4f..f371f1b32cfbe 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
diff --git a/fs/xfs/libxfs/xfs_bmap_btree.c b/fs/xfs/libxfs/xfs_bmap_btree.c
index 0c5dba21d94a1..bfe67e5d4d112 100644
--- a/fs/xfs/libxfs/xfs_bmap_btree.c
+++ b/fs/xfs/libxfs/xfs_bmap_btree.c
@@ -378,29 +378,17 @@ xfs_bmbt_cmp_key_with_cur(
 				      cur->bc_rec.b.br_startoff;
 }
 
-STATIC int64_t
+STATIC int
 xfs_bmbt_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)
 {
-	uint64_t			a = be64_to_cpu(k1->bmbt.br_startoff);
-	uint64_t			b = be64_to_cpu(k2->bmbt.br_startoff);
-
 	ASSERT(!mask || mask->bmbt.br_startoff);
 
-	/*
-	 * Note: This routine previously casted a and b to int64 and subtracted
-	 * them to generate a result.  This lead to problems if b was the
-	 * "maximum" key value (all ones) being signed incorrectly, hence this
-	 * somewhat less efficient version.
-	 */
-	if (a > b)
-		return 1;
-	if (b > a)
-		return -1;
-	return 0;
+	return cmp_int(be64_to_cpu(k1->bmbt.br_startoff),
+		       be64_to_cpu(k2->bmbt.br_startoff));
 }
 
 static xfs_failaddr_t
diff --git a/fs/xfs/libxfs/xfs_btree.h b/fs/xfs/libxfs/xfs_btree.h
index e72a10ba7ee6d..fecd9f0b93984 100644
--- a/fs/xfs/libxfs/xfs_btree.h
+++ b/fs/xfs/libxfs/xfs_btree.h
@@ -184,7 +184,7 @@ struct xfs_btree_ops {
 	 * each key field to be used in the comparison must contain a nonzero
 	 * value.
 	 */
-	int64_t (*cmp_two_keys)(struct xfs_btree_cur *cur,
+	int	(*cmp_two_keys)(struct xfs_btree_cur *cur,
 				const union xfs_btree_key *key1,
 				const union xfs_btree_key *key2,
 				const union xfs_btree_key *mask);
diff --git a/fs/xfs/libxfs/xfs_ialloc_btree.c b/fs/xfs/libxfs/xfs_ialloc_btree.c
index 0d0c6534259ac..ab9fce20b0838 100644
--- a/fs/xfs/libxfs/xfs_ialloc_btree.c
+++ b/fs/xfs/libxfs/xfs_ialloc_btree.c
@@ -274,7 +274,7 @@ xfs_inobt_cmp_key_with_cur(
 			  cur->bc_rec.i.ir_startino;
 }
 
-STATIC int64_t
+STATIC int
 xfs_inobt_cmp_two_keys(
 	struct xfs_btree_cur		*cur,
 	const union xfs_btree_key	*k1,
@@ -283,8 +283,8 @@ xfs_inobt_cmp_two_keys(
 {
 	ASSERT(!mask || mask->inobt.ir_startino);
 
-	return (int64_t)be32_to_cpu(k1->inobt.ir_startino) -
-			be32_to_cpu(k2->inobt.ir_startino);
+	return cmp_int(be32_to_cpu(k1->inobt.ir_startino),
+		       be32_to_cpu(k2->inobt.ir_startino));
 }
 
 static xfs_failaddr_t
diff --git a/fs/xfs/libxfs/xfs_refcount_btree.c b/fs/xfs/libxfs/xfs_refcount_btree.c
index 885fc3a0a304e..1c3996b11563d 100644
--- a/fs/xfs/libxfs/xfs_refcount_btree.c
+++ b/fs/xfs/libxfs/xfs_refcount_btree.c
@@ -188,7 +188,7 @@ xfs_refcountbt_cmp_key_with_cur(
 	return (int64_t)be32_to_cpu(kp->rc_startblock) - start;
 }
 
-STATIC int64_t
+STATIC int
 xfs_refcountbt_cmp_two_keys(
 	struct xfs_btree_cur		*cur,
 	const union xfs_btree_key	*k1,
@@ -197,8 +197,8 @@ xfs_refcountbt_cmp_two_keys(
 {
 	ASSERT(!mask || mask->refc.rc_startblock);
 
-	return (int64_t)be32_to_cpu(k1->refc.rc_startblock) -
-			be32_to_cpu(k2->refc.rc_startblock);
+	return cmp_int(be32_to_cpu(k1->refc.rc_startblock),
+		       be32_to_cpu(k2->refc.rc_startblock));
 }
 
 STATIC xfs_failaddr_t
diff --git a/fs/xfs/libxfs/xfs_rmap_btree.c b/fs/xfs/libxfs/xfs_rmap_btree.c
index 74288d311b680..3cccdb0d04182 100644
--- a/fs/xfs/libxfs/xfs_rmap_btree.c
+++ b/fs/xfs/libxfs/xfs_rmap_btree.c
@@ -273,7 +273,7 @@ xfs_rmapbt_cmp_key_with_cur(
 	return 0;
 }
 
-STATIC int64_t
+STATIC int
 xfs_rmapbt_cmp_two_keys(
 	struct xfs_btree_cur		*cur,
 	const union xfs_btree_key	*k1,
@@ -282,36 +282,31 @@ xfs_rmapbt_cmp_two_keys(
 {
 	const struct xfs_rmap_key	*kp1 = &k1->rmap;
 	const struct xfs_rmap_key	*kp2 = &k2->rmap;
-	int64_t				d;
-	__u64				x, y;
+	int				d;
 
 	/* Doesn't make sense to mask off the physical space part */
 	ASSERT(!mask || mask->rmap.rm_startblock);
 
-	d = (int64_t)be32_to_cpu(kp1->rm_startblock) -
-		     be32_to_cpu(kp2->rm_startblock);
+	d = cmp_int(be32_to_cpu(kp1->rm_startblock),
+		    be32_to_cpu(kp2->rm_startblock));
 	if (d)
 		return d;
 
 	if (!mask || mask->rmap.rm_owner) {
-		x = be64_to_cpu(kp1->rm_owner);
-		y = be64_to_cpu(kp2->rm_owner);
-		if (x > y)
-			return 1;
-		else if (y > x)
-			return -1;
+		d = cmp_int(be64_to_cpu(kp1->rm_owner),
+			    be64_to_cpu(kp2->rm_owner));
+		if (d)
+			return d;
 	}
 
 	if (!mask || mask->rmap.rm_offset) {
 		/* Doesn't make sense to allow offset but not owner */
 		ASSERT(!mask || mask->rmap.rm_owner);
 
-		x = offset_keymask(be64_to_cpu(kp1->rm_offset));
-		y = offset_keymask(be64_to_cpu(kp2->rm_offset));
-		if (x > y)
-			return 1;
-		else if (y > x)
-			return -1;
+		d = cmp_int(offset_keymask(be64_to_cpu(kp1->rm_offset)),
+			    offset_keymask(be64_to_cpu(kp2->rm_offset)));
+		if (d)
+			return d;
 	}
 
 	return 0;
diff --git a/fs/xfs/libxfs/xfs_rtrefcount_btree.c b/fs/xfs/libxfs/xfs_rtrefcount_btree.c
index 864c3aa664d76..d9f79ae579c69 100644
--- a/fs/xfs/libxfs/xfs_rtrefcount_btree.c
+++ b/fs/xfs/libxfs/xfs_rtrefcount_btree.c
@@ -170,7 +170,7 @@ xfs_rtrefcountbt_cmp_key_with_cur(
 	return (int64_t)be32_to_cpu(kp->rc_startblock) - start;
 }
 
-STATIC int64_t
+STATIC int
 xfs_rtrefcountbt_cmp_two_keys(
 	struct xfs_btree_cur		*cur,
 	const union xfs_btree_key	*k1,
@@ -179,8 +179,8 @@ xfs_rtrefcountbt_cmp_two_keys(
 {
 	ASSERT(!mask || mask->refc.rc_startblock);
 
-	return (int64_t)be32_to_cpu(k1->refc.rc_startblock) -
-			be32_to_cpu(k2->refc.rc_startblock);
+	return cmp_int(be32_to_cpu(k1->refc.rc_startblock),
+		       be32_to_cpu(k2->refc.rc_startblock));
 }
 
 static xfs_failaddr_t
diff --git a/fs/xfs/libxfs/xfs_rtrmap_btree.c b/fs/xfs/libxfs/xfs_rtrmap_btree.c
index b48336086ca7e..231a189ea2fe6 100644
--- a/fs/xfs/libxfs/xfs_rtrmap_btree.c
+++ b/fs/xfs/libxfs/xfs_rtrmap_btree.c
@@ -215,7 +215,7 @@ xfs_rtrmapbt_cmp_key_with_cur(
 	return 0;
 }
 
-STATIC int64_t
+STATIC int
 xfs_rtrmapbt_cmp_two_keys(
 	struct xfs_btree_cur		*cur,
 	const union xfs_btree_key	*k1,
@@ -224,36 +224,31 @@ xfs_rtrmapbt_cmp_two_keys(
 {
 	const struct xfs_rmap_key	*kp1 = &k1->rmap;
 	const struct xfs_rmap_key	*kp2 = &k2->rmap;
-	int64_t				d;
-	__u64				x, y;
+	int				d;
 
 	/* Doesn't make sense to mask off the physical space part */
 	ASSERT(!mask || mask->rmap.rm_startblock);
 
-	d = (int64_t)be32_to_cpu(kp1->rm_startblock) -
-		     be32_to_cpu(kp2->rm_startblock);
+	d = cmp_int(be32_to_cpu(kp1->rm_startblock),
+		    be32_to_cpu(kp2->rm_startblock));
 	if (d)
 		return d;
 
 	if (!mask || mask->rmap.rm_owner) {
-		x = be64_to_cpu(kp1->rm_owner);
-		y = be64_to_cpu(kp2->rm_owner);
-		if (x > y)
-			return 1;
-		else if (y > x)
-			return -1;
+		d = cmp_int(be64_to_cpu(kp1->rm_owner),
+			    be64_to_cpu(kp2->rm_owner));
+		if (d)
+			return d;
 	}
 
 	if (!mask || mask->rmap.rm_offset) {
 		/* Doesn't make sense to allow offset but not owner */
 		ASSERT(!mask || mask->rmap.rm_owner);
 
-		x = offset_keymask(be64_to_cpu(kp1->rm_offset));
-		y = offset_keymask(be64_to_cpu(kp2->rm_offset));
-		if (x > y)
-			return 1;
-		else if (y > x)
-			return -1;
+		d = cmp_int(offset_keymask(be64_to_cpu(kp1->rm_offset)),
+			    offset_keymask(be64_to_cpu(kp2->rm_offset)));
+		if (d)
+			return d;
 	}
 
 	return 0;
diff --git a/fs/xfs/scrub/rcbag_btree.c b/fs/xfs/scrub/rcbag_btree.c
index 523ffd0da77a3..46598817b2391 100644
--- a/fs/xfs/scrub/rcbag_btree.c
+++ b/fs/xfs/scrub/rcbag_btree.c
@@ -68,7 +68,7 @@ rcbagbt_cmp_key_with_cur(
 	return 0;
 }
 
-STATIC int64_t
+STATIC int
 rcbagbt_cmp_two_keys(
 	struct xfs_btree_cur		*cur,
 	const union xfs_btree_key	*k1,
@@ -80,17 +80,8 @@ rcbagbt_cmp_two_keys(
 
 	ASSERT(mask == NULL);
 
-	if (kp1->rbg_startblock > kp2->rbg_startblock)
-		return 1;
-	if (kp1->rbg_startblock < kp2->rbg_startblock)
-		return -1;
-
-	if (kp1->rbg_blockcount > kp2->rbg_blockcount)
-		return 1;
-	if (kp1->rbg_blockcount < kp2->rbg_blockcount)
-		return -1;
-
-	return 0;
+	return cmp_int(kp1->rbg_startblock, kp2->rbg_startblock) ?:
+	       cmp_int(kp1->rbg_blockcount, kp2->rbg_blockcount);
 }
 
 STATIC int