[PATCH v11 22/26] block/rnbd: server: functionality for IO submission to file or block dev

[Jack Wang <jinpu.wang@cloud.ionos.com>]

This provides helper functions for IO submission to file or block dev.

Signed-off-by: Danil Kipnis <danil.kipnis@cloud.ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@cloud.ionos.com>
---
 drivers/block/rnbd/rnbd-srv-dev.c | 94 +++++++++++++++++++++++++++++++
 drivers/block/rnbd/rnbd-srv-dev.h | 88 +++++++++++++++++++++++++++++
 2 files changed, 182 insertions(+)
 create mode 100644 drivers/block/rnbd/rnbd-srv-dev.c
 create mode 100644 drivers/block/rnbd/rnbd-srv-dev.h

diff --git a/drivers/block/rnbd/rnbd-srv-dev.c b/drivers/block/rnbd/rnbd-srv-dev.c
new file mode 100644
index 000000000000..370f4a43e10c
--- /dev/null
+++ b/drivers/block/rnbd/rnbd-srv-dev.c
@@ -0,0 +1,94 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * RDMA Network Block Driver
+ *
+ * Copyright (c) 2014 - 2018 ProfitBricks GmbH. All rights reserved.
+ * Copyright (c) 2018 - 2019 1&1 IONOS Cloud GmbH. All rights reserved.
+ * Copyright (c) 2019 - 2020 1&1 IONOS SE. All rights reserved.
+ */
+#undef pr_fmt
+#define pr_fmt(fmt) KBUILD_MODNAME " L" __stringify(__LINE__) ": " fmt
+
+#include "rnbd-srv-dev.h"
+#include "rnbd-log.h"
+
+struct rnbd_dev *rnbd_dev_open(const char *path, fmode_t flags,
+			       void (*io_cb)(void *priv, int error))
+{
+	struct rnbd_dev *dev;
+	int ret;
+
+	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+	if (!dev)
+		return ERR_PTR(-ENOMEM);
+
+	dev->blk_open_flags = flags;
+	dev->bdev = blkdev_get_by_path(path, flags, THIS_MODULE);
+	ret = PTR_ERR_OR_ZERO(dev->bdev);
+	if (ret)
+		goto err;
+
+	dev->blk_open_flags	= flags;
+	dev->io_cb		= io_cb;
+	bdevname(dev->bdev, dev->name);
+
+	return dev;
+
+err:
+	kfree(dev);
+	return ERR_PTR(ret);
+}
+
+void rnbd_dev_close(struct rnbd_dev *dev)
+{
+	blkdev_put(dev->bdev, dev->blk_open_flags);
+	kfree(dev);
+}
+
+static void rnbd_dev_bi_end_io(struct bio *bio)
+{
+	struct rnbd_dev_blk_io *io = bio->bi_private;
+
+	io->dev->io_cb(io->priv, blk_status_to_errno(bio->bi_status));
+	bio_put(bio);
+	kfree(io);
+}
+
+int rnbd_dev_submit_io(struct rnbd_dev *dev, sector_t sector, void *data,
+			size_t len, u32 bi_size, enum rnbd_io_flags flags,
+			short prio, void *priv)
+{
+	struct request_queue *q = bdev_get_queue(dev->bdev);
+	struct rnbd_dev_blk_io *io;
+	struct bio *bio;
+
+	/* check if the buffer is suitable for bdev */
+	if (WARN_ON(!blk_rq_aligned(q, (unsigned long)data, len)))
+		return -EINVAL;
+
+	/* Generate bio with pages pointing to the rdma buffer */
+	bio = bio_map_kern(q, data, len, GFP_KERNEL);
+	if (IS_ERR(bio))
+		return PTR_ERR(bio);
+
+	io = kmalloc(sizeof(*io), GFP_KERNEL);
+	if (unlikely(!io)) {
+		bio_put(bio);
+		return -ENOMEM;
+	}
+
+	io->dev		= dev;
+	io->priv	= priv;
+
+	bio->bi_end_io		= rnbd_dev_bi_end_io;
+	bio->bi_private		= io;
+	bio->bi_opf		= rnbd_to_bio_flags(flags);
+	bio->bi_iter.bi_sector	= sector;
+	bio->bi_iter.bi_size	= bi_size;
+	bio_set_prio(bio, prio);
+	bio_set_dev(bio, dev->bdev);
+
+	submit_bio(bio);
+
+	return 0;
+}
diff --git a/drivers/block/rnbd/rnbd-srv-dev.h b/drivers/block/rnbd/rnbd-srv-dev.h
new file mode 100644
index 000000000000..6d07b9323f84
--- /dev/null
+++ b/drivers/block/rnbd/rnbd-srv-dev.h
@@ -0,0 +1,88 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * RDMA Network Block Driver
+ *
+ * Copyright (c) 2014 - 2018 ProfitBricks GmbH. All rights reserved.
+ * Copyright (c) 2018 - 2019 1&1 IONOS Cloud GmbH. All rights reserved.
+ * Copyright (c) 2019 - 2020 1&1 IONOS SE. All rights reserved.
+ */
+#ifndef RNBD_SRV_DEV_H
+#define RNBD_SRV_DEV_H
+
+#include <linux/fs.h>
+#include "rnbd-proto.h"
+
+struct rnbd_dev {
+	struct block_device	*bdev;
+	fmode_t			blk_open_flags;
+	char			name[BDEVNAME_SIZE];
+	void			(*io_cb)(void *priv, int error);
+};
+
+struct rnbd_dev_blk_io {
+	struct rnbd_dev *dev;
+	void		 *priv;
+};
+
+/**
+ * rnbd_dev_open() - Open a device
+ * @flags:	open flags
+ * @io_cb:	is called when I/O finished
+ */
+struct rnbd_dev *rnbd_dev_open(const char *path, fmode_t flags,
+			       void (*io_cb)(void *priv, int error));
+
+/**
+ * rnbd_dev_close() - Close a device
+ */
+void rnbd_dev_close(struct rnbd_dev *dev);
+
+static inline int rnbd_dev_get_max_segs(const struct rnbd_dev *dev)
+{
+	return queue_max_segments(bdev_get_queue(dev->bdev));
+}
+
+static inline int rnbd_dev_get_max_hw_sects(const struct rnbd_dev *dev)
+{
+	return queue_max_hw_sectors(bdev_get_queue(dev->bdev));
+}
+
+static inline int rnbd_dev_get_secure_discard(const struct rnbd_dev *dev)
+{
+	return blk_queue_secure_erase(bdev_get_queue(dev->bdev));
+}
+
+static inline int rnbd_dev_get_max_discard_sects(const struct rnbd_dev *dev)
+{
+	if (!blk_queue_discard(bdev_get_queue(dev->bdev)))
+		return 0;
+
+	return blk_queue_get_max_sectors(bdev_get_queue(dev->bdev),
+					 REQ_OP_DISCARD);
+}
+
+static inline int rnbd_dev_get_discard_granularity(const struct rnbd_dev *dev)
+{
+	return bdev_get_queue(dev->bdev)->limits.discard_granularity;
+}
+
+static inline int rnbd_dev_get_discard_alignment(const struct rnbd_dev *dev)
+{
+	return bdev_get_queue(dev->bdev)->limits.discard_alignment;
+}
+
+/**
+ * rnbd_dev_submit_io() - Submit an I/O to the disk
+ * @dev:	device to that the I/O is submitted
+ * @sector:	address to read/write data to
+ * @data:	I/O data to write or buffer to read I/O date into
+ * @len:	length of @data
+ * @bi_size:	Amount of data that will be read/written
+ * @prio:       IO priority
+ * @priv:	private data passed to @io_fn
+ */
+int rnbd_dev_submit_io(struct rnbd_dev *dev, sector_t sector, void *data,
+			size_t len, u32 bi_size, enum rnbd_io_flags flags,
+			short prio, void *priv);
+
+#endif /* RNBD_SRV_DEV_H */
-- 
2.17.1