[PATCHv4 5/9] block: add a helper function for dio alignment

[Keith Busch <kbusch@fb.com>]

From: Keith Busch <kbusch@kernel.org>

This will make it easier to add more complex acceptable alignment
criteria in the future.

Signed-off-by: Keith Busch <kbusch@kernel.org>
---
 block/fops.c | 32 +++++++++++++++++++++-----------
 1 file changed, 21 insertions(+), 11 deletions(-)

diff --git a/block/fops.c b/block/fops.c
index b9b83030e0df..bd6c2e13a4e3 100644
--- a/block/fops.c
+++ b/block/fops.c
@@ -42,6 +42,16 @@ static unsigned int dio_bio_write_op(struct kiocb *iocb)
 	return op;
 }
 
+static int blkdev_dio_aligned(struct block_device *bdev, loff_t pos,
+			      struct iov_iter *iter)
+{
+	if ((pos | iov_iter_alignment(iter)) &
+	    (bdev_logical_block_size(bdev) - 1))
+		return -EINVAL;
+
+	return 0;
+}
+
 #define DIO_INLINE_BIO_VECS 4
 
 static ssize_t __blkdev_direct_IO_simple(struct kiocb *iocb,
@@ -54,9 +64,9 @@ static ssize_t __blkdev_direct_IO_simple(struct kiocb *iocb,
 	struct bio bio;
 	ssize_t ret;
 
-	if ((pos | iov_iter_alignment(iter)) &
-	    (bdev_logical_block_size(bdev) - 1))
-		return -EINVAL;
+	ret = blkdev_dio_aligned(bdev, pos, iter);
+	if (ret)
+		return ret;
 
 	if (nr_pages <= DIO_INLINE_BIO_VECS)
 		vecs = inline_vecs;
@@ -171,11 +181,11 @@ static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
 	bool is_read = (iov_iter_rw(iter) == READ), is_sync;
 	unsigned int opf = is_read ? REQ_OP_READ : dio_bio_write_op(iocb);
 	loff_t pos = iocb->ki_pos;
-	int ret = 0;
+	int ret;
 
-	if ((pos | iov_iter_alignment(iter)) &
-	    (bdev_logical_block_size(bdev) - 1))
-		return -EINVAL;
+	ret = blkdev_dio_aligned(bdev, pos, iter);
+	if (ret)
+		return ret;
 
 	if (iocb->ki_flags & IOCB_ALLOC_CACHE)
 		opf |= REQ_ALLOC_CACHE;
@@ -296,11 +306,11 @@ static ssize_t __blkdev_direct_IO_async(struct kiocb *iocb,
 	struct blkdev_dio *dio;
 	struct bio *bio;
 	loff_t pos = iocb->ki_pos;
-	int ret = 0;
+	int ret;
 
-	if ((pos | iov_iter_alignment(iter)) &
-	    (bdev_logical_block_size(bdev) - 1))
-		return -EINVAL;
+	ret = blkdev_dio_aligned(bdev, pos, iter);
+	if (ret)
+		return ret;
 
 	if (iocb->ki_flags & IOCB_ALLOC_CACHE)
 		opf |= REQ_ALLOC_CACHE;
-- 
2.30.2