[mirror_ubuntu-bionic-kernel.git] / include / net / 9p / client.h

/*
 * include/net/9p/client.h
 *
 * 9P Client Definitions
 *
 *  Copyright (C) 2008 by Eric Van Hensbergen <ericvh@gmail.com>
 *  Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2
 *  as published by the Free Software Foundation.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to:
 *  Free Software Foundation
 *  51 Franklin Street, Fifth Floor
 *  Boston, MA  02111-1301  USA
 *
 */

#ifndef NET_9P_CLIENT_H
#define NET_9P_CLIENT_H

/* Number of requests per row */
#define P9_ROW_MAXTAG 255

/**
 * enum p9_trans_status - different states of underlying transports
 * @Connected: transport is connected and healthy
 * @Disconnected: transport has been disconnected
 * @Hung: transport is connected by wedged
 *
 * This enumeration details the various states a transport
 * instatiation can be in.
 */

enum p9_trans_status {
	Connected,
	Disconnected,
	Hung,
};

/**
 * enum p9_req_status_t - virtio request status
 * @REQ_STATUS_IDLE: request slot unused
 * @REQ_STATUS_ALLOC: request has been allocated but not sent
 * @REQ_STATUS_SENT: request sent to server
 * @REQ_STATUS_FLSH: a flush has been sent for this request
 * @REQ_STATUS_RCVD: response received from server
 * @REQ_STATUS_FLSHD: request has been flushed
 * @REQ_STATUS_ERR: request encountered an error on the client side
 *
 * The @REQ_STATUS_IDLE state is used to mark a request slot as unused
 * but use is actually tracked by the idpool structure which handles tag
 * id allocation.
 *
 */

enum p9_req_status_t {
	REQ_STATUS_IDLE,
	REQ_STATUS_ALLOC,
	REQ_STATUS_SENT,
	REQ_STATUS_FLSH,
	REQ_STATUS_RCVD,
	REQ_STATUS_FLSHD,
	REQ_STATUS_ERROR,
};

/**
 * struct p9_req_t - request slots
 * @status: status of this request slot
 * @t_err: transport error
 * @wq: wait_queue for the client to block on for this request
 * @tc: the request fcall structure
 * @rc: the response fcall structure
 * @aux: transport specific data (provided for trans_fd migration)
 *
 * Transport use an array to track outstanding requests
 * instead of a list.  While this may incurr overhead during initial
 * allocation or expansion, it makes request lookup much easier as the
 * tag id is a index into an array.  (We use tag+1 so that we can accomodate
 * the -1 tag for the T_VERSION request).
 * This also has the nice effect of only having to allocate wait_queues
 * once, instead of constantly allocating and freeing them.  Its possible
 * other resources could benefit from this scheme as well.
 *
 */

struct p9_req_t {
	int status;
	int t_err;
	wait_queue_head_t *wq;
	struct p9_fcall *tc;
	struct p9_fcall *rc;
	u16 flush_tag;
	void *aux;
};

/**
 * struct p9_client - per client instance state
 * @lock: protect @fidlist
 * @msize: maximum data size negotiated by protocol
 * @dotu: extension flags negotiated by protocol
 * @trans_mod: module API instantiated with this client
 * @trans: tranport instance state and API
 * @conn: connection state information used by trans_fd
 * @fidpool: fid handle accounting for session
 * @fidlist: List of active fid handles
 * @tagpool - transaction id accounting for session
 * @reqs - 2D array of requests
 * @max_tag - current maximum tag id allocated
 *
 * The client structure is used to keep track of various per-client
 * state that has been instantiated.
 * In order to minimize per-transaction overhead we use a
 * simple array to lookup requests instead of a hash table
 * or linked list.  In order to support larger number of
 * transactions, we make this a 2D array, allocating new rows
 * when we need to grow the total number of the transactions.
 *
 * Each row is 256 requests and we'll support up to 256 rows for
 * a total of 64k concurrent requests per session.
 *
 * Bugs: duplicated data and potentially unnecessary elements.
 */

struct p9_client {
	spinlock_t lock; /* protect client structure */
	int msize;
	unsigned char dotu;
	struct p9_trans_module *trans_mod;
	enum p9_trans_status status;
	void *trans;
	struct p9_conn *conn;

	struct p9_idpool *fidpool;
	struct list_head fidlist;

	struct p9_idpool *tagpool;
	struct p9_req_t *reqs[P9_ROW_MAXTAG];
	int max_tag;
};

/**
 * struct p9_fid - file system entity handle
 * @clnt: back pointer to instantiating &p9_client
 * @fid: numeric identifier for this handle
 * @mode: current mode of this fid (enum?)
 * @qid: the &p9_qid server identifier this handle points to
 * @iounit: the server reported maximum transaction size for this file
 * @uid: the numeric uid of the local user who owns this handle
 * @aux: transport specific information (unused?)
 * @rdir_fpos: tracks offset of file position when reading directory contents
 * @rdir_pos: (unused?)
 * @rdir_fcall: holds response of last directory read request
 * @flist: per-client-instance fid tracking
 * @dlist: per-dentry fid tracking
 *
 * TODO: This needs lots of explanation.
 */

struct p9_fid {
	struct p9_client *clnt;
	u32 fid;
	int mode;
	struct p9_qid qid;
	u32 iounit;
	uid_t uid;
	void *aux;

	int rdir_fpos;
	int rdir_pos;
	struct p9_fcall *rdir_fcall;
	struct list_head flist;
	struct list_head dlist;	/* list of all fids attached to a dentry */
};

struct p9_client *p9_client_create(const char *dev_name, char *options);
void p9_client_destroy(struct p9_client *clnt);
void p9_client_disconnect(struct p9_client *clnt);
struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
					char *uname, u32 n_uname, char *aname);
struct p9_fid *p9_client_auth(struct p9_client *clnt, char *uname,
						u32 n_uname, char *aname);
struct p9_fid *p9_client_walk(struct p9_fid *oldfid, int nwname, char **wnames,
								int clone);
int p9_client_open(struct p9_fid *fid, int mode);
int p9_client_fcreate(struct p9_fid *fid, char *name, u32 perm, int mode,
							char *extension);
int p9_client_clunk(struct p9_fid *fid);
int p9_client_remove(struct p9_fid *fid);
int p9_client_read(struct p9_fid *fid, char *data, u64 offset, u32 count);
int p9_client_readn(struct p9_fid *fid, char *data, u64 offset, u32 count);
int p9_client_write(struct p9_fid *fid, char *data, u64 offset, u32 count);
int p9_client_uread(struct p9_fid *fid, char __user *data, u64 offset,
								u32 count);
int p9_client_uwrite(struct p9_fid *fid, const char __user *data, u64 offset,
								u32 count);
struct p9_stat *p9_client_stat(struct p9_fid *fid);
int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst);
struct p9_stat *p9_client_dirread(struct p9_fid *fid, u64 offset);

struct p9_req_t *p9_tag_alloc(struct p9_client *, u16);
struct p9_req_t *p9_tag_lookup(struct p9_client *, u16);

#endif /* NET_9P_CLIENT_H */
Commit	Line	Data
bd238fb4 LI	1	/*
	2	* include/net/9p/client.h
	3	*
	4	* 9P Client Definitions
	5	*
8a0dc95f	6	* Copyright (C) 2008 by Eric Van Hensbergen <ericvh@gmail.com>
bd238fb4 LI	7	* Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
	8	*
	9	* This program is free software; you can redistribute it and/or modify
	10	* it under the terms of the GNU General Public License version 2
	11	* as published by the Free Software Foundation.
	12	*
	13	* This program is distributed in the hope that it will be useful,
	14	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	15	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	16	* GNU General Public License for more details.
	17	*
	18	* You should have received a copy of the GNU General Public License
	19	* along with this program; if not, write to:
	20	* Free Software Foundation
	21	* 51 Franklin Street, Fifth Floor
	22	* Boston, MA 02111-1301 USA
	23	*
	24	*/
	25
	26	#ifndef NET_9P_CLIENT_H
	27	#define NET_9P_CLIENT_H
	28
fea511a6 EVH	29	/* Number of requests per row */
	30	#define P9_ROW_MAXTAG 255
	31
8b81ef58 EVH	32	/**
	33	* enum p9_trans_status - different states of underlying transports
	34	* @Connected: transport is connected and healthy
	35	* @Disconnected: transport has been disconnected
	36	* @Hung: transport is connected by wedged
	37	*
	38	* This enumeration details the various states a transport
	39	* instatiation can be in.
	40	*/
	41
	42	enum p9_trans_status {
	43	Connected,
	44	Disconnected,
	45	Hung,
	46	};
	47
fea511a6 EVH	48	/**
	49	* enum p9_req_status_t - virtio request status
	50	* @REQ_STATUS_IDLE: request slot unused
	51	* @REQ_STATUS_ALLOC: request has been allocated but not sent
	52	* @REQ_STATUS_SENT: request sent to server
	53	* @REQ_STATUS_FLSH: a flush has been sent for this request
	54	* @REQ_STATUS_RCVD: response received from server
	55	* @REQ_STATUS_FLSHD: request has been flushed
	56	* @REQ_STATUS_ERR: request encountered an error on the client side
	57	*
	58	* The @REQ_STATUS_IDLE state is used to mark a request slot as unused
	59	* but use is actually tracked by the idpool structure which handles tag
	60	* id allocation.
	61	*
	62	*/
	63
	64	enum p9_req_status_t {
	65	REQ_STATUS_IDLE,
	66	REQ_STATUS_ALLOC,
	67	REQ_STATUS_SENT,
	68	REQ_STATUS_FLSH,
	69	REQ_STATUS_RCVD,
	70	REQ_STATUS_FLSHD,
	71	REQ_STATUS_ERROR,
	72	};
	73
	74	/**
	75	* struct p9_req_t - request slots
	76	* @status: status of this request slot
	77	* @t_err: transport error
	78	* @wq: wait_queue for the client to block on for this request
	79	* @tc: the request fcall structure
	80	* @rc: the response fcall structure
	81	* @aux: transport specific data (provided for trans_fd migration)
	82	*
	83	* Transport use an array to track outstanding requests
	84	* instead of a list. While this may incurr overhead during initial
	85	* allocation or expansion, it makes request lookup much easier as the
	86	* tag id is a index into an array. (We use tag+1 so that we can accomodate
	87	* the -1 tag for the T_VERSION request).
	88	* This also has the nice effect of only having to allocate wait_queues
	89	* once, instead of constantly allocating and freeing them. Its possible
	90	* other resources could benefit from this scheme as well.
	91	*
	92	*/
	93
	94	struct p9_req_t {
	95	int status;
	96	int t_err;
	97	wait_queue_head_t *wq;
	98	struct p9_fcall *tc;
	99	struct p9_fcall *rc;
	100	u16 flush_tag;
	101	void *aux;
	102	};
	103
ee443996 EVH	104	/**
	105	* struct p9_client - per client instance state
	106	* @lock: protect @fidlist
	107	* @msize: maximum data size negotiated by protocol
	108	* @dotu: extension flags negotiated by protocol
	109	* @trans_mod: module API instantiated with this client
	110	* @trans: tranport instance state and API
	111	* @conn: connection state information used by trans_fd
	112	* @fidpool: fid handle accounting for session
	113	* @fidlist: List of active fid handles
fea511a6 EVH	114	* @tagpool - transaction id accounting for session
	115	* @reqs - 2D array of requests
	116	* @max_tag - current maximum tag id allocated
ee443996 EVH	117	*
	118	* The client structure is used to keep track of various per-client
	119	* state that has been instantiated.
fea511a6 EVH	120	* In order to minimize per-transaction overhead we use a
	121	* simple array to lookup requests instead of a hash table
	122	* or linked list. In order to support larger number of
	123	* transactions, we make this a 2D array, allocating new rows
	124	* when we need to grow the total number of the transactions.
	125	*
	126	* Each row is 256 requests and we'll support up to 256 rows for
	127	* a total of 64k concurrent requests per session.
ee443996 EVH	128	*
	129	* Bugs: duplicated data and potentially unnecessary elements.
	130	*/
	131
bd238fb4 LI	132	struct p9_client {
	133	spinlock_t lock; /* protect client structure */
	134	int msize;
	135	unsigned char dotu;
8a0dc95f	136	struct p9_trans_module *trans_mod;
8b81ef58 EVH	137	enum p9_trans_status status;
8b81ef58 EVH	138	void *trans;
bd238fb4 LI	139	struct p9_conn *conn;
	140
	141	struct p9_idpool *fidpool;
	142	struct list_head fidlist;
fea511a6 EVH	143
	144	struct p9_idpool *tagpool;
	145	struct p9_req_t *reqs[P9_ROW_MAXTAG];
	146	int max_tag;
bd238fb4 LI	147	};
bd238fb4 LI	148
ee443996 EVH	149	/**
	150	* struct p9_fid - file system entity handle
	151	* @clnt: back pointer to instantiating &p9_client
	152	* @fid: numeric identifier for this handle
	153	* @mode: current mode of this fid (enum?)
	154	* @qid: the &p9_qid server identifier this handle points to
	155	* @iounit: the server reported maximum transaction size for this file
	156	* @uid: the numeric uid of the local user who owns this handle
	157	* @aux: transport specific information (unused?)
	158	* @rdir_fpos: tracks offset of file position when reading directory contents
	159	* @rdir_pos: (unused?)
	160	* @rdir_fcall: holds response of last directory read request
	161	* @flist: per-client-instance fid tracking
	162	* @dlist: per-dentry fid tracking
	163	*
	164	* TODO: This needs lots of explanation.
	165	*/
	166
bd238fb4 LI	167	struct p9_fid {
	168	struct p9_client *clnt;
	169	u32 fid;
	170	int mode;
	171	struct p9_qid qid;
	172	u32 iounit;
	173	uid_t uid;
	174	void *aux;
	175
	176	int rdir_fpos;
	177	int rdir_pos;
	178	struct p9_fcall *rdir_fcall;
	179	struct list_head flist;
	180	struct list_head dlist; /* list of all fids attached to a dentry */
	181	};
	182
8a0dc95f	183	struct p9_client p9_client_create(const char dev_name, char *options);
bd238fb4 LI	184	void p9_client_destroy(struct p9_client *clnt);
	185	void p9_client_disconnect(struct p9_client *clnt);
	186	struct p9_fid p9_client_attach(struct p9_client clnt, struct p9_fid *afid,
ba17674f LI	187	char uname, u32 n_uname, char aname);
	188	struct p9_fid p9_client_auth(struct p9_client clnt, char *uname,
	189	u32 n_uname, char *aname);
bd238fb4 LI	190	struct p9_fid p9_client_walk(struct p9_fid oldfid, int nwname, char **wnames,
	191	int clone);
	192	int p9_client_open(struct p9_fid *fid, int mode);
	193	int p9_client_fcreate(struct p9_fid fid, char name, u32 perm, int mode,
	194	char *extension);
	195	int p9_client_clunk(struct p9_fid *fid);
	196	int p9_client_remove(struct p9_fid *fid);
	197	int p9_client_read(struct p9_fid fid, char data, u64 offset, u32 count);
	198	int p9_client_readn(struct p9_fid fid, char data, u64 offset, u32 count);
	199	int p9_client_write(struct p9_fid fid, char data, u64 offset, u32 count);
	200	int p9_client_uread(struct p9_fid fid, char __user data, u64 offset,
	201	u32 count);
	202	int p9_client_uwrite(struct p9_fid fid, const char __user data, u64 offset,
	203	u32 count);
	204	struct p9_stat p9_client_stat(struct p9_fid fid);
	205	int p9_client_wstat(struct p9_fid fid, struct p9_wstat wst);
	206	struct p9_stat p9_client_dirread(struct p9_fid fid, u64 offset);
	207
fea511a6 EVH	208	struct p9_req_t p9_tag_alloc(struct p9_client , u16);
	209	struct p9_req_t p9_tag_lookup(struct p9_client , u16);
	210
bd238fb4	211	#endif /* NET_9P_CLIENT_H */