1 files changed, 151 insertions, 0 deletions

diff --git a/include/linux/nfs_page.h b/include/linux/nfs_page.h
new file mode 100644
index 000000000000..39e4895bcdb4
--- /dev/null
+++ b/include/linux/nfs_page.h
@@ -0,0 +1,151 @@
+/*
+ * 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 */