[07/25] xfs: refactor non-power-of-two alignment checks

Commit Message

Darrick J. Wong May 26, 2023, 1:16 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(-)

Patch

diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 31eca20c854a..3f23dc4e07ae 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 (XFS_IS_REALTIME_INODE(ip) && !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 (XFS_IS_REALTIME_INODE(ip) && !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 09f727f712fe..b8c61b48cb51 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;
+}
+
 int xfs_rw_bdev(struct block_device *bdev, sector_t sector, unsigned int count,
 		char *data, enum req_op op);