/* SPDX-License-Identifier: GPL-2.0 */
 * fs/nfs/nfs4session.h
 * Copyright (c) 2012 Trond Myklebust <Trond.Myklebust@netapp.com>

/* maximum number of slots to use */
#define NFS4_MAX_SLOT_TABLE (1024U)
#define NFS4_NO_SLOT ((u32)-1)


/* Sessions slot seqid */
struct nfs4_slot {
	struct nfs4_slot_table	*table;
	struct nfs4_slot	*next;
	unsigned long		generation;
	u32			slot_nr;
	u32		 	seq_nr;
	u32		 	seq_nr_last_acked;
	u32		 	seq_nr_highest_sent;
	unsigned int		privileged : 1,
				seq_done : 1;

/* Sessions */
enum nfs4_slot_tbl_state {

struct nfs4_slot_table {
	struct nfs4_session *session;		/* Parent session */
	struct nfs4_slot *slots;		/* seqid per slot */
	unsigned long   used_slots[SLOT_TABLE_SZ]; /* used/unused bitmap */
	spinlock_t	slot_tbl_lock;
	struct rpc_wait_queue	slot_tbl_waitq;	/* allocators may wait here */
	wait_queue_head_t	slot_waitq;	/* Completion wait on slot */
	u32		max_slots;		/* # slots in table */
	u32		max_slotid;		/* Max allowed slotid value */
	u32		highest_used_slotid;	/* sent to server on each SEQ.
						 * op for dynamic resizing */
	u32		target_highest_slotid;	/* Server max_slot target */
	u32		server_highest_slotid;	/* Server highest slotid */
	s32		d_target_highest_slotid; /* Derivative */
	s32		d2_target_highest_slotid; /* 2nd derivative */
	unsigned long	generation;		/* Generation counter for
						   target_highest_slotid */
	struct completion complete;
	unsigned long	slot_tbl_state;

 * Session related parameters
struct nfs4_session {
	struct nfs4_sessionid		sess_id;
	u32				flags;
	unsigned long			session_state;
	u32				hash_alg;
	u32				ssv_len;

	/* The fore and back channel */
	struct nfs4_channel_attrs	fc_attrs;
	struct nfs4_slot_table		fc_slot_table;
	struct nfs4_channel_attrs	bc_attrs;
	struct nfs4_slot_table		bc_slot_table;
	struct nfs_client		*clp;

enum nfs4_session_state {

extern int nfs4_setup_slot_table(struct nfs4_slot_table *tbl,
		unsigned int max_reqs, const char *queue);
extern void nfs4_shutdown_slot_table(struct nfs4_slot_table *tbl);
extern struct nfs4_slot *nfs4_alloc_slot(struct nfs4_slot_table *tbl);
extern struct nfs4_slot *nfs4_lookup_slot(struct nfs4_slot_table *tbl, u32 slotid);
extern int nfs4_slot_wait_on_seqid(struct nfs4_slot_table *tbl,
		u32 slotid, u32 seq_nr,
		unsigned long timeout);
extern bool nfs4_try_to_lock_slot(struct nfs4_slot_table *tbl, struct nfs4_slot *slot);
extern void nfs4_free_slot(struct nfs4_slot_table *tbl, struct nfs4_slot *slot);
extern void nfs4_slot_tbl_drain_complete(struct nfs4_slot_table *tbl);
bool nfs41_wake_and_assign_slot(struct nfs4_slot_table *tbl,
		struct nfs4_slot *slot);
void nfs41_wake_slot_table(struct nfs4_slot_table *tbl);

static inline bool nfs4_slot_tbl_draining(struct nfs4_slot_table *tbl)
	return !!test_bit(NFS4_SLOT_TBL_DRAINING, &tbl->slot_tbl_state);

static inline bool nfs4_test_locked_slot(const struct nfs4_slot_table *tbl,
		u32 slotid)
	return !!test_bit(slotid, tbl->used_slots);

static inline struct nfs4_session *nfs4_get_session(const struct nfs_client *clp)
	return clp->cl_session;

#if defined(CONFIG_NFS_V4_1)
extern void nfs41_set_target_slotid(struct nfs4_slot_table *tbl,
		u32 target_highest_slotid);
extern void nfs41_update_target_slotid(struct nfs4_slot_table *tbl,
		struct nfs4_slot *slot,
		struct nfs4_sequence_res *res);

extern int nfs4_setup_session_slot_tables(struct nfs4_session *ses);

extern struct nfs4_session *nfs4_alloc_session(struct nfs_client *clp);
extern void nfs4_destroy_session(struct nfs4_session *session);
extern int nfs4_init_session(struct nfs_client *clp);
extern int nfs4_init_ds_session(struct nfs_client *, unsigned long);

 * Determine if sessions are in use.
static inline int nfs4_has_session(const struct nfs_client *clp)
	if (clp->cl_session)
		return 1;
	return 0;

static inline int nfs4_has_persistent_session(const struct nfs_client *clp)
	if (nfs4_has_session(clp))
		return (clp->cl_session->flags & SESSION4_PERSIST);
	return 0;

static inline void nfs4_copy_sessionid(struct nfs4_sessionid *dst,
		const struct nfs4_sessionid *src)
	memcpy(dst->data, src->data, NFS4_MAX_SESSIONID_LEN);

#ifdef CONFIG_CRC32
 * nfs_session_id_hash - calculate the crc32 hash for the session id
 * @session - pointer to session
#define nfs_session_id_hash(sess_id) \
	(~crc32_le(0xFFFFFFFF, &(sess_id)->data[0], sizeof((sess_id)->data)))
#define nfs_session_id_hash(session) (0)
#else /* defined(CONFIG_NFS_V4_1) */

static inline int nfs4_init_session(struct nfs_client *clp)
	return 0;

 * Determine if sessions are in use.
static inline int nfs4_has_session(const struct nfs_client *clp)
	return 0;

static inline int nfs4_has_persistent_session(const struct nfs_client *clp)
	return 0;

#define nfs_session_id_hash(session) (0)

#endif /* defined(CONFIG_NFS_V4_1) */
#endif /* IS_ENABLED(CONFIG_NFS_V4) */