[6/6] xfs: refactor non-power-of-two alignment checks

Commit Message

Darrick J. Wong Feb. 27, 2024, 2:20 a.m. UTC

From: Darrick J. Wong <[e-mail]>

Create a helper function that can compute if a 64-bit number is an
integer multiple of a 32-bit number, where the 32-bit number is not
required to be an even power of two.  This is needed for some new code
for the realtime device, where we can set 37k allocation units and then
have to remap them.

Signed-off-by: Darrick J. Wong <[e-mail]>
---
 fs/xfs/xfs_file.c  |   12 +++---------
 fs/xfs/xfs_linux.h |    5 +++++
 2 files changed, 8 insertions(+), 9 deletions(-)

Comments

Christoph Hellwig Feb. 27, 2024, 3:51 p.m. UTC | #1

Looks good:

Reviewed-by: Christoph Hellwig <[e-mail]>

Patch

diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 64278f8acaeee..d1d4158441bd9 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -47,15 +47,9 @@  xfs_is_falloc_aligned(
 {
 	unsigned int		alloc_unit = xfs_inode_alloc_unitsize(ip);
 
-	if (!is_power_of_2(alloc_unit)) {
-		u32	mod;
-
-		div_u64_rem(pos, alloc_unit, &mod);
-		if (mod)
-			return false;
-		div_u64_rem(len, alloc_unit, &mod);
-		return mod == 0;
-	}
+	if (!is_power_of_2(alloc_unit))
+		return isaligned_64(pos, alloc_unit) &&
+		       isaligned_64(len, alloc_unit);
 
 	return !((pos | len) & (alloc_unit - 1));
 }
diff --git a/fs/xfs/xfs_linux.h b/fs/xfs/xfs_linux.h
index 73854ad981eb5..439f10b4a77a5 100644
--- a/fs/xfs/xfs_linux.h
+++ b/fs/xfs/xfs_linux.h
@@ -199,6 +199,11 @@  static inline uint64_t howmany_64(uint64_t x, uint32_t y)
 	return x;
 }
 
+static inline bool isaligned_64(uint64_t x, uint32_t y)
+{
+	return do_div(x, y) == 0;
+}
+
 /* If @b is a power of 2, return log2(b).  Else return -1. */
 static inline int8_t log2_if_power2(unsigned long b)
 {