diff mbox series

[1/1] xfs: Use abs_diff instead of XFS_ABSDIFF

Message ID 174257453362.474546.12679550361506145616.stgit@frogsfrogsfrogs (mailing list archive)
State New
Headers show
Series [1/1] xfs: Use abs_diff instead of XFS_ABSDIFF | expand

Commit Message

Darrick J. Wong March 21, 2025, 4:31 p.m. UTC 
From: Matthew Wilcox (Oracle) <willy@infradead.org>

Source kernel commit: ca3ac4bf4dc307cea5781dccccf41c1d14c2f82f

We have a central definition for this function since 2023, used by
a number of different parts of the kernel.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
---
 include/platform_defs.h |   19 +++++++++++++++++++
 libxfs/xfs_alloc.c      |    8 +++-----
 2 files changed, 22 insertions(+), 5 deletions(-)
diff mbox series

Patch

diff --git a/include/platform_defs.h b/include/platform_defs.h
index 051ee25a5b4fea..9af7b4318f8917 100644
--- a/include/platform_defs.h
+++ b/include/platform_defs.h
@@ -261,4 +261,23 @@  static inline bool __must_check __must_check_overflow(bool overflow)
 	__builtin_add_overflow(__a, __b, __d);	\
 }))
 
+/**
+ * abs_diff - return absolute value of the difference between the arguments
+ * @a: the first argument
+ * @b: the second argument
+ *
+ * @a and @b have to be of the same type. With this restriction we compare
+ * signed to signed and unsigned to unsigned. The result is the subtraction
+ * the smaller of the two from the bigger, hence result is always a positive
+ * value.
+ *
+ * Return: an absolute value of the difference between the @a and @b.
+ */
+#define abs_diff(a, b) ({			\
+	typeof(a) __a = (a);			\
+	typeof(b) __b = (b);			\
+	(void)(&__a == &__b);			\
+	__a > __b ? (__a - __b) : (__b - __a);	\
+})
+
 #endif	/* __XFS_PLATFORM_DEFS_H__ */
diff --git a/libxfs/xfs_alloc.c b/libxfs/xfs_alloc.c
index 9aebe7227a6148..6675be78a7dae8 100644
--- a/libxfs/xfs_alloc.c
+++ b/libxfs/xfs_alloc.c
@@ -29,8 +29,6 @@  struct kmem_cache	*xfs_extfree_item_cache;
 
 struct workqueue_struct *xfs_alloc_wq;
 
-#define XFS_ABSDIFF(a,b)	(((a) <= (b)) ? ((b) - (a)) : ((a) - (b)))
-
 #define	XFSA_FIXUP_BNO_OK	1
 #define	XFSA_FIXUP_CNT_OK	2
 
@@ -406,8 +404,8 @@  xfs_alloc_compute_diff(
 		if (newbno1 != NULLAGBLOCK && newbno2 != NULLAGBLOCK) {
 			if (newlen1 < newlen2 ||
 			    (newlen1 == newlen2 &&
-			     XFS_ABSDIFF(newbno1, wantbno) >
-			     XFS_ABSDIFF(newbno2, wantbno)))
+			     abs_diff(newbno1, wantbno) >
+			     abs_diff(newbno2, wantbno)))
 				newbno1 = newbno2;
 		} else if (newbno2 != NULLAGBLOCK)
 			newbno1 = newbno2;
@@ -423,7 +421,7 @@  xfs_alloc_compute_diff(
 	} else
 		newbno1 = freeend - wantlen;
 	*newbnop = newbno1;
-	return newbno1 == NULLAGBLOCK ? 0 : XFS_ABSDIFF(newbno1, wantbno);
+	return newbno1 == NULLAGBLOCK ? 0 : abs_diff(newbno1, wantbno);
 }
 
 /*