backing_dev.h

  1/* SPDX-License-Identifier: GPL-2.0-or-later */
  2#ifndef _BACKING_DEV_H
  3#define _BACKING_DEV_H
  4
  5#include <linux/device-mapper.h>
  6
  7#include "pcache_internal.h"
  8
  9struct pcache_backing_dev_req;
 10typedef void (*backing_req_end_fn_t)(struct pcache_backing_dev_req *backing_req, int ret);
 11
 12#define BACKING_DEV_REQ_TYPE_REQ		1
 13#define BACKING_DEV_REQ_TYPE_KMEM		2
 14
 15#define BACKING_DEV_REQ_INLINE_BVECS		4
 16
 17struct pcache_request;
 18struct pcache_backing_dev_req {
 19	u8				type;
 20	struct bio			bio;
 21	struct pcache_backing_dev	*backing_dev;
 22
 23	void				*priv_data;
 24	backing_req_end_fn_t		end_req;
 25
 26	struct list_head		node;
 27	int				ret;
 28
 29	union {
 30		struct {
 31			struct pcache_request		*upper_req;
 32			u32				bio_off;
 33		} req;
 34		struct {
 35			struct bio_vec	inline_bvecs[BACKING_DEV_REQ_INLINE_BVECS];
 36			struct bio_vec	*bvecs;
 37			u32		n_vecs;
 38		} kmem;
 39	};
 40};
 41
 42struct pcache_backing_dev {
 43	struct pcache_cache		*cache;
 44
 45	struct dm_dev			*dm_dev;
 46	mempool_t			req_pool;
 47	mempool_t			bvec_pool;
 48
 49	struct list_head		submit_list;
 50	spinlock_t			submit_lock;
 51	struct work_struct		req_submit_work;
 52
 53	struct list_head		complete_list;
 54	spinlock_t			complete_lock;
 55	struct work_struct		req_complete_work;
 56
 57	atomic_t			inflight_reqs;
 58	wait_queue_head_t		inflight_wq;
 59
 60	u64				dev_size;
 61};
 62
 63struct dm_pcache;
 64int backing_dev_start(struct dm_pcache *pcache);
 65void backing_dev_stop(struct dm_pcache *pcache);
 66
 67struct pcache_backing_dev_req_opts {
 68	u32 type;
 69	union {
 70		struct {
 71			struct pcache_request *upper_req;
 72			u32 req_off;
 73			u32 len;
 74		} req;
 75		struct {
 76			void *data;
 77			blk_opf_t opf;
 78			u32 len;
 79			u64 backing_off;
 80		} kmem;
 81	};
 82
 83	gfp_t gfp_mask;
 84	backing_req_end_fn_t	end_fn;
 85	void			*priv_data;
 86};
 87
 88static inline u32 backing_dev_req_coalesced_max_len(const void *data, u32 len)
 89{
 90	const void *p = data;
 91	u32 done = 0, in_page, to_advance;
 92	struct page *first_page, *next_page;
 93
 94	if (!is_vmalloc_addr(data))
 95		return len;
 96
 97	first_page = vmalloc_to_page(p);
 98advance:
 99	in_page = PAGE_SIZE - offset_in_page(p);
100	to_advance = min_t(u32, in_page, len - done);
101
102	done += to_advance;
103	p += to_advance;
104
105	if (done == len)
106		return done;
107
108	next_page = vmalloc_to_page(p);
109	if (zone_device_pages_have_same_pgmap(first_page, next_page))
110		goto advance;
111
112	return done;
113}
114
115void backing_dev_req_submit(struct pcache_backing_dev_req *backing_req, bool direct);
116void backing_dev_req_end(struct pcache_backing_dev_req *backing_req);
117struct pcache_backing_dev_req *backing_dev_req_create(struct pcache_backing_dev *backing_dev,
118						struct pcache_backing_dev_req_opts *opts);
119struct pcache_backing_dev_req *backing_dev_req_alloc(struct pcache_backing_dev *backing_dev,
120						struct pcache_backing_dev_req_opts *opts);
121void backing_dev_req_init(struct pcache_backing_dev_req *backing_req,
122			struct pcache_backing_dev_req_opts *opts);
123void backing_dev_flush(struct pcache_backing_dev *backing_dev);
124
125int pcache_backing_init(void);
126void pcache_backing_exit(void);
127#endif /* _BACKING_DEV_H */