block: Call blkdev_dio_unaligned() from blkdev_direct_IO()

blkdev_dio_unaligned() is called from __blkdev_direct_IO(),
__blkdev_direct_IO_simple(), and __blkdev_direct_IO_async(), and all these
are only called from blkdev_direct_IO().

Move the blkdev_dio_unaligned() call to the common callsite,
blkdev_direct_IO().

Pass those functions the bdev pointer from blkdev_direct_IO(), as it is
non-trivial to look up.

Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: John Garry <john.g.garry@oracle.com>
Link: https://lore.kernel.org/r/20240415122020.1541594-1-john.g.garry@oracle.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/fops.c

@@ -44,18 +44,15 @@ static bool blkdev_dio_unaligned(struct block_device *bdev, loff_t pos,
 #define DIO_INLINE_BIO_VECS 4
 
 static ssize_t __blkdev_direct_IO_simple(struct kiocb *iocb,
-		struct iov_iter *iter, unsigned int nr_pages)
+		struct iov_iter *iter, struct block_device *bdev,
+		unsigned int nr_pages)
 {
-	struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host);
 	struct bio_vec inline_vecs[DIO_INLINE_BIO_VECS], *vecs;
 	loff_t pos = iocb->ki_pos;
 	bool should_dirty = false;
 	struct bio bio;
 	ssize_t ret;
 
-	if (blkdev_dio_unaligned(bdev, pos, iter))
-		return -EINVAL;
-
 	if (nr_pages <= DIO_INLINE_BIO_VECS)
 		vecs = inline_vecs;
 	else {
@@ -161,9 +158,8 @@ static void blkdev_bio_end_io(struct bio *bio)
 }
 
 static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
-		unsigned int nr_pages)
+		struct block_device *bdev, unsigned int nr_pages)
 {
-	struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host);
 	struct blk_plug plug;
 	struct blkdev_dio *dio;
 	struct bio *bio;
@@ -172,9 +168,6 @@ static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
 	loff_t pos = iocb->ki_pos;
 	int ret = 0;
 
-	if (blkdev_dio_unaligned(bdev, pos, iter))
-		return -EINVAL;
-
 	if (iocb->ki_flags & IOCB_ALLOC_CACHE)
 		opf |= REQ_ALLOC_CACHE;
 	bio = bio_alloc_bioset(bdev, nr_pages, opf, GFP_KERNEL,
@@ -302,19 +295,16 @@ static void blkdev_bio_end_io_async(struct bio *bio)
 
 static ssize_t __blkdev_direct_IO_async(struct kiocb *iocb,
 					struct iov_iter *iter,
+					struct block_device *bdev,
 					unsigned int nr_pages)
 {
-	struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host);
 	bool is_read = iov_iter_rw(iter) == READ;
 	blk_opf_t opf = is_read ? REQ_OP_READ : dio_bio_write_op(iocb);
 	struct blkdev_dio *dio;
 	struct bio *bio;
 	loff_t pos = iocb->ki_pos;
 	int ret = 0;
 
-	if (blkdev_dio_unaligned(bdev, pos, iter))
-		return -EINVAL;
-
 	if (iocb->ki_flags & IOCB_ALLOC_CACHE)
 		opf |= REQ_ALLOC_CACHE;
 	bio = bio_alloc_bioset(bdev, nr_pages, opf, GFP_KERNEL,
@@ -368,18 +358,23 @@ static ssize_t __blkdev_direct_IO_async(struct kiocb *iocb,
 
 static ssize_t blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 {
+	struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host);
 	unsigned int nr_pages;
 
 	if (!iov_iter_count(iter))
 		return 0;
 
+	if (blkdev_dio_unaligned(bdev, iocb->ki_pos, iter))
+		return -EINVAL;
+
 	nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS + 1);
 	if (likely(nr_pages <= BIO_MAX_VECS)) {
 		if (is_sync_kiocb(iocb))
-			return __blkdev_direct_IO_simple(iocb, iter, nr_pages);
-		return __blkdev_direct_IO_async(iocb, iter, nr_pages);
+			return __blkdev_direct_IO_simple(iocb, iter, bdev,
+							nr_pages);
+		return __blkdev_direct_IO_async(iocb, iter, bdev, nr_pages);
 	}
-	return __blkdev_direct_IO(iocb, iter, bio_max_segs(nr_pages));
+	return __blkdev_direct_IO(iocb, iter, bdev, bio_max_segs(nr_pages));
 }
 
 static int blkdev_iomap_begin(struct inode *inode, loff_t offset, loff_t length,