[deliverable/linux.git] / include / linux / nfs_page.h

/*
 * linux/include/linux/nfs_page.h
 *
 * Copyright (C) 2000 Trond Myklebust
 *
 * NFS page cache wrapper.
 */

#ifndef _LINUX_NFS_PAGE_H
#define _LINUX_NFS_PAGE_H


#include <linux/list.h>
#include <linux/pagemap.h>
#include <linux/wait.h>
#include <linux/nfs_fs_sb.h>
#include <linux/sunrpc/auth.h>
#include <linux/nfs_xdr.h>

#include <asm/atomic.h>

/*
 * Valid flags for a dirty buffer
 */
#define PG_BUSY			0
#define PG_NEED_COMMIT		1
#define PG_NEED_RESCHED		2

struct nfs_page {
	struct list_head	wb_list,	/* Defines state of page: */
				*wb_list_head;	/*      read/write/commit */
	struct page		*wb_page;	/* page to read in/write out */
	struct nfs_open_context	*wb_context;	/* File state context info */
	atomic_t		wb_complete;	/* i/os we're waiting for */
	unsigned long		wb_index;	/* Offset >> PAGE_CACHE_SHIFT */
	unsigned int		wb_offset,	/* Offset & ~PAGE_CACHE_MASK */
				wb_pgbase,	/* Start of page data */
				wb_bytes;	/* Length of request */
	atomic_t		wb_count;	/* reference count */
	unsigned long		wb_flags;
	struct nfs_writeverf	wb_verf;	/* Commit cookie */
};

#define NFS_WBACK_BUSY(req)	(test_bit(PG_BUSY,&(req)->wb_flags))
#define NFS_NEED_COMMIT(req)	(test_bit(PG_NEED_COMMIT,&(req)->wb_flags))
#define NFS_NEED_RESCHED(req)	(test_bit(PG_NEED_RESCHED,&(req)->wb_flags))

extern	struct nfs_page *nfs_create_request(struct nfs_open_context *ctx,
					    struct inode *inode,
					    struct page *page,
					    unsigned int offset,
					    unsigned int count);
extern	void nfs_clear_request(struct nfs_page *req);
extern	void nfs_release_request(struct nfs_page *req);


extern	void nfs_list_add_request(struct nfs_page *, struct list_head *);

extern	int nfs_scan_list(struct list_head *, struct list_head *,
			  unsigned long, unsigned int);
extern	int nfs_coalesce_requests(struct list_head *, struct list_head *,
				  unsigned int);
extern  int nfs_wait_on_request(struct nfs_page *);
extern	void nfs_unlock_request(struct nfs_page *req);

/*
 * Lock the page of an asynchronous request without incrementing the wb_count
 */
static inline int
nfs_lock_request_dontget(struct nfs_page *req)
{
	if (test_and_set_bit(PG_BUSY, &req->wb_flags))
		return 0;
	return 1;
}

/*
 * Lock the page of an asynchronous request
 */
static inline int
nfs_lock_request(struct nfs_page *req)
{
	if (test_and_set_bit(PG_BUSY, &req->wb_flags))
		return 0;
	atomic_inc(&req->wb_count);
	return 1;
}


/**
 * nfs_list_remove_request - Remove a request from its wb_list
 * @req: request
 */
static inline void
nfs_list_remove_request(struct nfs_page *req)
{
	if (list_empty(&req->wb_list))
		return;
	if (!NFS_WBACK_BUSY(req)) {
		printk(KERN_ERR "NFS: unlocked request attempted removed from list!\n");
		BUG();
	}
	list_del_init(&req->wb_list);
	req->wb_list_head = NULL;
}

static inline int
nfs_defer_commit(struct nfs_page *req)
{
	if (test_and_set_bit(PG_NEED_COMMIT, &req->wb_flags))
		return 0;
	return 1;
}

static inline void
nfs_clear_commit(struct nfs_page *req)
{
	smp_mb__before_clear_bit();
	clear_bit(PG_NEED_COMMIT, &req->wb_flags);
	smp_mb__after_clear_bit();
}

static inline int
nfs_defer_reschedule(struct nfs_page *req)
{
	if (test_and_set_bit(PG_NEED_RESCHED, &req->wb_flags))
		return 0;
	return 1;
}

static inline void
nfs_clear_reschedule(struct nfs_page *req)
{
	smp_mb__before_clear_bit();
	clear_bit(PG_NEED_RESCHED, &req->wb_flags);
	smp_mb__after_clear_bit();
}

static inline struct nfs_page *
nfs_list_entry(struct list_head *head)
{
	return list_entry(head, struct nfs_page, wb_list);
}

static inline
loff_t req_offset(struct nfs_page *req)
{
	return (((loff_t)req->wb_index) << PAGE_CACHE_SHIFT) + req->wb_offset;
}

#endif /* _LINUX_NFS_PAGE_H */
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/include/linux/nfs_page.h
	3	*
	4	* Copyright (C) 2000 Trond Myklebust
	5	*
	6	* NFS page cache wrapper.
	7	*/
	8
	9	#ifndef _LINUX_NFS_PAGE_H
	10	#define _LINUX_NFS_PAGE_H
	11
	12
	13	#include <linux/list.h>
	14	#include <linux/pagemap.h>
	15	#include <linux/wait.h>
	16	#include <linux/nfs_fs_sb.h>
	17	#include <linux/sunrpc/auth.h>
	18	#include <linux/nfs_xdr.h>
	19
	20	#include <asm/atomic.h>
	21
	22	/*
	23	* Valid flags for a dirty buffer
	24	*/
	25	#define PG_BUSY 0
	26	#define PG_NEED_COMMIT 1
	27	#define PG_NEED_RESCHED 2
	28
	29	struct nfs_page {
	30	struct list_head wb_list, /* Defines state of page: */
	31	wb_list_head; / read/write/commit */
	32	struct page wb_page; / page to read in/write out */
	33	struct nfs_open_context wb_context; / File state context info */
	34	atomic_t wb_complete; /* i/os we're waiting for */
	35	unsigned long wb_index; /* Offset >> PAGE_CACHE_SHIFT */
	36	unsigned int wb_offset, /* Offset & ~PAGE_CACHE_MASK */
	37	wb_pgbase, /* Start of page data */
	38	wb_bytes; /* Length of request */
	39	atomic_t wb_count; /* reference count */
	40	unsigned long wb_flags;
	41	struct nfs_writeverf wb_verf; /* Commit cookie */
	42	};
	43
	44	#define NFS_WBACK_BUSY(req) (test_bit(PG_BUSY,&(req)->wb_flags))
	45	#define NFS_NEED_COMMIT(req) (test_bit(PG_NEED_COMMIT,&(req)->wb_flags))
	46	#define NFS_NEED_RESCHED(req) (test_bit(PG_NEED_RESCHED,&(req)->wb_flags))
	47
	48	extern struct nfs_page nfs_create_request(struct nfs_open_context ctx,
	49	struct inode *inode,
	50	struct page *page,
	51	unsigned int offset,
	52	unsigned int count);
	53	extern void nfs_clear_request(struct nfs_page *req);
	54	extern void nfs_release_request(struct nfs_page *req);
	55
	56
	57	extern void nfs_list_add_request(struct nfs_page , struct list_head );
	58
	59	extern int nfs_scan_list(struct list_head , struct list_head ,
	60	unsigned long, unsigned int);
	61	extern int nfs_coalesce_requests(struct list_head , struct list_head ,
	62	unsigned int);
	63	extern int nfs_wait_on_request(struct nfs_page *);
	64	extern void nfs_unlock_request(struct nfs_page *req);
65
66	/*
67	* Lock the page of an asynchronous request without incrementing the wb_count
68	*/
69	static inline int
70	nfs_lock_request_dontget(struct nfs_page *req)
71	{
72	if (test_and_set_bit(PG_BUSY, &req->wb_flags))
73	return 0;
74	return 1;
75	}
76
77	/*
78	* Lock the page of an asynchronous request
79	*/
80	static inline int
81	nfs_lock_request(struct nfs_page *req)
82	{
83	if (test_and_set_bit(PG_BUSY, &req->wb_flags))
84	return 0;
85	atomic_inc(&req->wb_count);
86	return 1;
87	}
88
89
90	/**
91	* nfs_list_remove_request - Remove a request from its wb_list
92	* @req: request
93	*/
94	static inline void
95	nfs_list_remove_request(struct nfs_page *req)
96	{
97	if (list_empty(&req->wb_list))
98	return;
99	if (!NFS_WBACK_BUSY(req)) {
100	printk(KERN_ERR "NFS: unlocked request attempted removed from list!\n");
101	BUG();
102	}
103	list_del_init(&req->wb_list);
104	req->wb_list_head = NULL;
105	}
106
107	static inline int
108	nfs_defer_commit(struct nfs_page *req)
109	{
110	if (test_and_set_bit(PG_NEED_COMMIT, &req->wb_flags))
111	return 0;
112	return 1;
113	}
114
115	static inline void
116	nfs_clear_commit(struct nfs_page *req)
117	{
118	smp_mb__before_clear_bit();
119	clear_bit(PG_NEED_COMMIT, &req->wb_flags);
120	smp_mb__after_clear_bit();
121	}
122
123	static inline int
124	nfs_defer_reschedule(struct nfs_page *req)
125	{
126	if (test_and_set_bit(PG_NEED_RESCHED, &req->wb_flags))
127	return 0;
128	return 1;
129	}
130
131	static inline void
132	nfs_clear_reschedule(struct nfs_page *req)
133	{
134	smp_mb__before_clear_bit();
135	clear_bit(PG_NEED_RESCHED, &req->wb_flags);
136	smp_mb__after_clear_bit();
137	}
138
139	static inline struct nfs_page *
140	nfs_list_entry(struct list_head *head)
141	{
142	return list_entry(head, struct nfs_page, wb_list);
143	}
144
145	static inline
146	loff_t req_offset(struct nfs_page *req)
147	{
148	return (((loff_t)req->wb_index) << PAGE_CACHE_SHIFT) + req->wb_offset;
149	}
150
151	#endif /* _LINUX_NFS_PAGE_H */