1 files changed, 127 insertions, 0 deletions
diff --git a/drivers/md/dm-pcache/backing_dev.h b/drivers/md/dm-pcache/backing_dev.h
new file mode 100644
index 000000000000..b371cba483b9
--- /dev/null
+++ b/drivers/md/dm-pcache/backing_dev.h
@@ -0,0 +1,127 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef _BACKING_DEV_H
+#define _BACKING_DEV_H
+
+#include <linux/device-mapper.h>
+
+#include "pcache_internal.h"
+
+struct pcache_backing_dev_req;
+typedef void (*backing_req_end_fn_t)(struct pcache_backing_dev_req *backing_req, int ret);
+
+#define BACKING_DEV_REQ_TYPE_REQ		1
+#define BACKING_DEV_REQ_TYPE_KMEM		2
+
+#define BACKING_DEV_REQ_INLINE_BVECS		4
+
+struct pcache_request;
+struct pcache_backing_dev_req {
+	u8				type;
+	struct bio			bio;
+	struct pcache_backing_dev	*backing_dev;
+
+	void				*priv_data;
+	backing_req_end_fn_t		end_req;
+
+	struct list_head		node;
+	int				ret;
+
+	union {
+		struct {
+			struct pcache_request		*upper_req;
+			u32				bio_off;
+		} req;
+		struct {
+			struct bio_vec	inline_bvecs[BACKING_DEV_REQ_INLINE_BVECS];
+			struct bio_vec	*bvecs;
+			u32		n_vecs;
+		} kmem;
+	};
+};
+
+struct pcache_backing_dev {
+	struct pcache_cache		*cache;
+
+	struct dm_dev			*dm_dev;
+	mempool_t			req_pool;
+	mempool_t			bvec_pool;
+
+	struct list_head		submit_list;
+	spinlock_t			submit_lock;
+	struct work_struct		req_submit_work;
+
+	struct list_head		complete_list;
+	spinlock_t			complete_lock;
+	struct work_struct		req_complete_work;
+
+	atomic_t			inflight_reqs;
+	wait_queue_head_t		inflight_wq;
+
+	u64				dev_size;
+};
+
+struct dm_pcache;
+int backing_dev_start(struct dm_pcache *pcache);
+void backing_dev_stop(struct dm_pcache *pcache);
+
+struct pcache_backing_dev_req_opts {
+	u32 type;
+	union {
+		struct {
+			struct pcache_request *upper_req;
+			u32 req_off;
+			u32 len;
+		} req;
+		struct {
+			void *data;
+			blk_opf_t opf;
+			u32 len;
+			u64 backing_off;
+		} kmem;
+	};
+
+	gfp_t gfp_mask;
+	backing_req_end_fn_t	end_fn;
+	void			*priv_data;
+};
+
+static inline u32 backing_dev_req_coalesced_max_len(const void *data, u32 len)
+{
+	const void *p = data;
+	u32 done = 0, in_page, to_advance;
+	struct page *first_page, *next_page;
+
+	if (!is_vmalloc_addr(data))
+		return len;
+
+	first_page = vmalloc_to_page(p);
+advance:
+	in_page = PAGE_SIZE - offset_in_page(p);
+	to_advance = min_t(u32, in_page, len - done);
+
+	done += to_advance;
+	p += to_advance;
+
+	if (done == len)
+		return done;
+
+	next_page = vmalloc_to_page(p);
+	if (zone_device_pages_have_same_pgmap(first_page, next_page))
+		goto advance;
+
+	return done;
+}
+
+void backing_dev_req_submit(struct pcache_backing_dev_req *backing_req, bool direct);
+void backing_dev_req_end(struct pcache_backing_dev_req *backing_req);
+struct pcache_backing_dev_req *backing_dev_req_create(struct pcache_backing_dev *backing_dev,
+						struct pcache_backing_dev_req_opts *opts);
+struct pcache_backing_dev_req *backing_dev_req_alloc(struct pcache_backing_dev *backing_dev,
+						struct pcache_backing_dev_req_opts *opts);
+void backing_dev_req_init(struct pcache_backing_dev_req *backing_req,
+			struct pcache_backing_dev_req_opts *opts);
+void backing_dev_flush(struct pcache_backing_dev *backing_dev);
+
+int pcache_backing_init(void);
+void pcache_backing_exit(void);
+#endif /* _BACKING_DEV_H */