f2fs: simplify f2fs_force_buffered_io()

f2fs only allows direct I/O that is aligned to the filesystem block
size.  Given that fact, simplify f2fs_force_buffered_io() by removing
the redundant call to block_unaligned_IO().

This makes it easier to reuse this code for STATX_DIOALIGN.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Acked-by: Jaegeuk Kim <jaegeuk@kernel.org>
Link: https://lore.kernel.org/r/20220827065851.135710-7-ebiggers@kernel.org

fs/f2fs/file.c

@@ -808,22 +808,9 @@ int f2fs_truncate(struct inode *inode)
 	return 0;
 }
 
-static int block_unaligned_IO(struct inode *inode, struct kiocb *iocb,
-			      struct iov_iter *iter)
-{
-	unsigned int i_blkbits = READ_ONCE(inode->i_blkbits);
-	unsigned int blocksize_mask = (1 << i_blkbits) - 1;
-	loff_t offset = iocb->ki_pos;
-	unsigned long align = offset | iov_iter_alignment(iter);
-
-	return align & blocksize_mask;
-}
-
-static bool f2fs_force_buffered_io(struct inode *inode,
-				   struct kiocb *iocb, struct iov_iter *iter)
+static bool f2fs_force_buffered_io(struct inode *inode, int rw)
 {
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
-	int rw = iov_iter_rw(iter);
 
 	if (!fscrypt_dio_supported(inode))
 		return true;
@@ -836,13 +823,9 @@ static bool f2fs_force_buffered_io(struct inode *inode,
 	if (f2fs_is_multi_device(sbi) && !sbi->aligned_blksize)
 		return true;
 
-	if (f2fs_lfs_mode(sbi) && (rw == WRITE)) {
-		if (block_unaligned_IO(inode, iocb, iter))
-			return true;
-		if (F2FS_IO_ALIGNED(sbi))
-			return true;
-	}
-	if (is_sbi_flag_set(F2FS_I_SB(inode), SBI_CP_DISABLED))
+	if (f2fs_lfs_mode(sbi) && rw == WRITE && F2FS_IO_ALIGNED(sbi))
+		return true;
+	if (is_sbi_flag_set(sbi, SBI_CP_DISABLED))
 		return true;
 
 	return false;
@@ -4222,7 +4205,7 @@ static bool f2fs_should_use_dio(struct inode *inode, struct kiocb *iocb,
 	if (!(iocb->ki_flags & IOCB_DIRECT))
 		return false;
 
-	if (f2fs_force_buffered_io(inode, iocb, iter))
+	if (f2fs_force_buffered_io(inode, iov_iter_rw(iter)))
 		return false;
 
 	/*