include/net/9p/client.h - kernel/windcharger - Git at Google

 /*
  * 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_UNSENT: request waiting to be 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_ERROR: 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_UNSENT,
 	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
  * @flush_tag: tag of request being flushed (for flush requests)
  * @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)
  * @req_list: link for higher level objects to chain requests
  *
  * 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;
 	void *aux;

 	struct list_head req_list;
 };

 /**
  * 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
  * @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;
 	struct list_head flist;
 	struct list_head dlist;	/* list of all fids attached to a dentry */
 };

 int p9_client_version(struct p9_client *);
 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, char __user *udata,
 							u64 offset, u32 count);
 int p9_client_write(struct p9_fid *fid, char *data, const char __user *udata,
 							u64 offset, u32 count);
 struct p9_wstat *p9_client_stat(struct p9_fid *fid);
 int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst);

 struct p9_req_t *p9_tag_lookup(struct p9_client *, u16);
 void p9_client_cb(struct p9_client *c, struct p9_req_t *req);

 int p9_parse_header(struct p9_fcall *, int32_t *, int8_t *, int16_t *, int);
 int p9stat_read(char *, int, struct p9_wstat *, int);
 void p9stat_free(struct p9_wstat *);


 #endif /* 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_UNSENT: request waiting to be 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_ERROR: 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_UNSENT,
	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
	* @flush_tag: tag of request being flushed (for flush requests)
	* @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)
	* @req_list: link for higher level objects to chain requests
	*
	* 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;
	void *aux;

	struct list_head req_list;
	};

	/**
	* 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
	* @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;
	struct list_head flist;
	struct list_head dlist; /* list of all fids attached to a dentry */
	};

	int p9_client_version(struct p9_client *);
	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, char __user *udata,
	u64 offset, u32 count);
	int p9_client_write(struct p9_fid fid, char data, const char __user *udata,
	u64 offset, u32 count);
	struct p9_wstat p9_client_stat(struct p9_fid fid);
	int p9_client_wstat(struct p9_fid fid, struct p9_wstat wst);

	struct p9_req_t p9_tag_lookup(struct p9_client , u16);
	void p9_client_cb(struct p9_client c, struct p9_req_t req);

	int p9_parse_header(struct p9_fcall , int32_t , int8_t , int16_t , int);
	int p9stat_read(char , int, struct p9_wstat , int);
	void p9stat_free(struct p9_wstat *);


	#endif /* NET_9P_CLIENT_H */