Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 1189 insertions, 0 deletions

diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
new file mode 100644
index 000000000000..900f5bc7e336
--- /dev/null
+++ b/net/sunrpc/cache.c
@@ -0,0 +1,1189 @@
+/*
+ * net/sunrpc/cache.c
+ *
+ * Generic code for various authentication-related caches
+ * used by sunrpc clients and servers.
+ *
+ * Copyright (C) 2002 Neil Brown <neilb@cse.unsw.edu.au>
+ *
+ * Released under terms in GPL version 2.  See COPYING.
+ *
+ */
+
+#include <linux/types.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/slab.h>
+#include <linux/signal.h>
+#include <linux/sched.h>
+#include <linux/kmod.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/ctype.h>
+#include <asm/uaccess.h>
+#include <linux/poll.h>
+#include <linux/seq_file.h>
+#include <linux/proc_fs.h>
+#include <linux/net.h>
+#include <linux/workqueue.h>
+#include <asm/ioctls.h>
+#include <linux/sunrpc/types.h>
+#include <linux/sunrpc/cache.h>
+#include <linux/sunrpc/stats.h>
+
+#define  RPCDBG_FACILITY RPCDBG_CACHE
+
+static void cache_defer_req(struct cache_req *req, struct cache_head *item);
+static void cache_revisit_request(struct cache_head *item);
+
+void cache_init(struct cache_head *h)
+{
+        time_t now = get_seconds();
+        h->next = NULL;
+        h->flags = 0;
+        atomic_set(&h->refcnt, 1);
+        h->expiry_time = now + CACHE_NEW_EXPIRY;
+        h->last_refresh = now;
+}
+
+
+static int cache_make_upcall(struct cache_detail *detail, struct cache_head *h);
+/*
+ * This is the generic cache management routine for all
+ * the authentication caches.
+ * It checks the currency of a cache item and will (later)
+ * initiate an upcall to fill it if needed.
+ *
+ *
+ * Returns 0 if the cache_head can be used, or cache_puts it and returns
+ * -EAGAIN if upcall is pending,
+ * -ENOENT if cache entry was negative
+ */
+int cache_check(struct cache_detail *detail,
+                    struct cache_head *h, struct cache_req *rqstp)
+{
+        int rv;
+        long refresh_age, age;
+
+        /* First decide return status as best we can */
+        if (!test_bit(CACHE_VALID, &h->flags) ||
+            h->expiry_time < get_seconds())
+                rv = -EAGAIN;
+        else if (detail->flush_time > h->last_refresh)
+                rv = -EAGAIN;
+        else {
+                /* entry is valid */
+                if (test_bit(CACHE_NEGATIVE, &h->flags))
+                        rv = -ENOENT;
+                else rv = 0;
+        }
+
+        /* now see if we want to start an upcall */
+        refresh_age = (h->expiry_time - h->last_refresh);
+        age = get_seconds() - h->last_refresh;
+
+        if (rqstp == NULL) {
+                if (rv == -EAGAIN)
+                        rv = -ENOENT;
+        } else if (rv == -EAGAIN || age > refresh_age/2) {
+                dprintk("Want update, refage=%ld, age=%ld\n", refresh_age, age);
+                if (!test_and_set_bit(CACHE_PENDING, &h->flags)) {
+                        switch (cache_make_upcall(detail, h)) {
+                        case -EINVAL:
+                                clear_bit(CACHE_PENDING, &h->flags);
+                                if (rv == -EAGAIN) {
+                                        set_bit(CACHE_NEGATIVE, &h->flags);
+                                        cache_fresh(detail, h, get_seconds()+CACHE_NEW_EXPIRY);
+                                        rv = -ENOENT;
+                                }
+                                break;
+
+                        case -EAGAIN:
+                                clear_bit(CACHE_PENDING, &h->flags);
+                                cache_revisit_request(h);
+                                break;
+                        }
+                }
+        }
+
+        if (rv == -EAGAIN)
+                cache_defer_req(rqstp, h);
+
+        if (rv && h)
+                detail->cache_put(h, detail);
+        return rv;
+}
+
+static void queue_loose(struct cache_detail *detail, struct cache_head *ch);
+
+void cache_fresh(struct cache_detail *detail,
+                 struct cache_head *head, time_t expiry)
+{
+
+        head->expiry_time = expiry;
+        head->last_refresh = get_seconds();
+        if (!test_and_set_bit(CACHE_VALID, &head->flags))
+                cache_revisit_request(head);
+        if (test_and_clear_bit(CACHE_PENDING, &head->flags))
+                queue_loose(detail, head);
+}
+
+/*
+ * caches need to be periodically cleaned.
+ * For this we maintain a list of cache_detail and
+ * a current pointer into that list and into the table
+ * for that entry.
+ *
+ * Each time clean_cache is called it finds the next non-empty entry
+ * in the current table and walks the list in that entry
+ * looking for entries that can be removed.
+ *
+ * An entry gets removed if:
+ * - The expiry is before current time
+ * - The last_refresh time is before the flush_time for that cache
+ *
+ * later we might drop old entries with non-NEVER expiry if that table
+ * is getting 'full' for some definition of 'full'
+ *
+ * The question of "how often to scan a table" is an interesting one
+ * and is answered in part by the use of the "nextcheck" field in the
+ * cache_detail.
+ * When a scan of a table begins, the nextcheck field is set to a time
+ * that is well into the future.
+ * While scanning, if an expiry time is found that is earlier than the
+ * current nextcheck time, nextcheck is set to that expiry time.
+ * If the flush_time is ever set to a time earlier than the nextcheck
+ * time, the nextcheck time is then set to that flush_time.
+ *
+ * A table is then only scanned if the current time is at least
+ * the nextcheck time.
+ * 
+ */
+
+static LIST_HEAD(cache_list);
+static DEFINE_SPINLOCK(cache_list_lock);
+static struct cache_detail *current_detail;
+static int current_index;
+
+static struct file_operations cache_file_operations;
+static struct file_operations content_file_operations;
+static struct file_operations cache_flush_operations;
+
+static void do_cache_clean(void *data);
+static DECLARE_WORK(cache_cleaner, do_cache_clean, NULL);
+
+void cache_register(struct cache_detail *cd)
+{
+        cd->proc_ent = proc_mkdir(cd->name, proc_net_rpc);
+        if (cd->proc_ent) {
+                struct proc_dir_entry *p;
+                cd->proc_ent->owner = THIS_MODULE;
+                cd->channel_ent = cd->content_ent = NULL;
+                
+                p = create_proc_entry("flush", S_IFREG|S_IRUSR|S_IWUSR,
+                                      cd->proc_ent);
+                cd->flush_ent =  p;
+                if (p) {
+                        p->proc_fops = &cache_flush_operations;
+                        p->owner = THIS_MODULE;
+                        p->data = cd;
+                }
+ 
+                if (cd->cache_request || cd->cache_parse) {
+                        p = create_proc_entry("channel", S_IFREG|S_IRUSR|S_IWUSR,
+                                              cd->proc_ent);
+                        cd->channel_ent = p;
+                        if (p) {
+                                p->proc_fops = &cache_file_operations;
+                                p->owner = THIS_MODULE;
+                                p->data = cd;
+                        }
+                }
+                if (cd->cache_show) {
+                        p = create_proc_entry("content", S_IFREG|S_IRUSR|S_IWUSR,
+                                              cd->proc_ent);
+                        cd->content_ent = p;
+                        if (p) {
+                                p->proc_fops = &content_file_operations;
+                                p->owner = THIS_MODULE;
+                                p->data = cd;
+                        }
+                }
+        }
+        rwlock_init(&cd->hash_lock);
+        INIT_LIST_HEAD(&cd->queue);
+        spin_lock(&cache_list_lock);
+        cd->nextcheck = 0;
+        cd->entries = 0;
+        atomic_set(&cd->readers, 0);
+        cd->last_close = 0;
+        cd->last_warn = -1;
+        list_add(&cd->others, &cache_list);
+        spin_unlock(&cache_list_lock);
+
+        /* start the cleaning process */
+        schedule_work(&cache_cleaner);
+}
+
+int cache_unregister(struct cache_detail *cd)
+{
+        cache_purge(cd);
+        spin_lock(&cache_list_lock);
+        write_lock(&cd->hash_lock);
+        if (cd->entries || atomic_read(&cd->inuse)) {
+                write_unlock(&cd->hash_lock);
+                spin_unlock(&cache_list_lock);
+                return -EBUSY;
+        }
+        if (current_detail == cd)
+                current_detail = NULL;
+        list_del_init(&cd->others);
+        write_unlock(&cd->hash_lock);
+        spin_unlock(&cache_list_lock);
+        if (cd->proc_ent) {
+                if (cd->flush_ent)
+                        remove_proc_entry("flush", cd->proc_ent);
+                if (cd->channel_ent)
+                        remove_proc_entry("channel", cd->proc_ent);
+                if (cd->content_ent)
+                        remove_proc_entry("content", cd->proc_ent);
+
+                cd->proc_ent = NULL;
+                remove_proc_entry(cd->name, proc_net_rpc);
+        }
+        if (list_empty(&cache_list)) {
+                /* module must be being unloaded so its safe to kill the worker */
+                cancel_delayed_work(&cache_cleaner);
+                flush_scheduled_work();
+        }
+        return 0;
+}
+
+/* clean cache tries to find something to clean
+ * and cleans it.
+ * It returns 1 if it cleaned something,
+ *            0 if it didn't find anything this time
+ *           -1 if it fell off the end of the list.
+ */
+static int cache_clean(void)
+{
+        int rv = 0;
+        struct list_head *next;
+
+        spin_lock(&cache_list_lock);
+
+        /* find a suitable table if we don't already have one */
+        while (current_detail == NULL ||
+            current_index >= current_detail->hash_size) {
+                if (current_detail)
+                        next = current_detail->others.next;
+                else
+                        next = cache_list.next;
+                if (next == &cache_list) {
+                        current_detail = NULL;
+                        spin_unlock(&cache_list_lock);
+                        return -1;
+                }
+                current_detail = list_entry(next, struct cache_detail, others);
+                if (current_detail->nextcheck > get_seconds())
+                        current_index = current_detail->hash_size;
+                else {
+                        current_index = 0;
+                        current_detail->nextcheck = get_seconds()+30*60;
+                }
+        }
+
+        /* find a non-empty bucket in the table */
+        while (current_detail &&
+               current_index < current_detail->hash_size &&
+               current_detail->hash_table[current_index] == NULL)
+                current_index++;
+
+        /* find a cleanable entry in the bucket and clean it, or set to next bucket */
+        
+        if (current_detail && current_index < current_detail->hash_size) {
+                struct cache_head *ch, **cp;
+                struct cache_detail *d;
+                
+                write_lock(&current_detail->hash_lock);
+
+                /* Ok, now to clean this strand */
+                        
+                cp = & current_detail->hash_table[current_index];
+                ch = *cp;
+                for (; ch; cp= & ch->next, ch= *cp) {
+                        if (current_detail->nextcheck > ch->expiry_time)
+                                current_detail->nextcheck = ch->expiry_time+1;
+                        if (ch->expiry_time >= get_seconds()
+                            && ch->last_refresh >= current_detail->flush_time
+                                )
+                                continue;
+                        if (test_and_clear_bit(CACHE_PENDING, &ch->flags))
+                                queue_loose(current_detail, ch);
+
+                        if (atomic_read(&ch->refcnt) == 1)
+                                break;
+                }
+                if (ch) {
+                        *cp = ch->next;
+                        ch->next = NULL;
+                        current_detail->entries--;
+                        rv = 1;
+                }
+                write_unlock(&current_detail->hash_lock);
+                d = current_detail;
+                if (!ch)
+                        current_index ++;
+                spin_unlock(&cache_list_lock);
+                if (ch)
+                        d->cache_put(ch, d);
+        } else
+                spin_unlock(&cache_list_lock);
+
+        return rv;
+}
+
+/*
+ * We want to regularly clean the cache, so we need to schedule some work ...
+ */
+static void do_cache_clean(void *data)
+{
+        int delay = 5;
+        if (cache_clean() == -1)
+                delay = 30*HZ;
+
+        if (list_empty(&cache_list))
+                delay = 0;
+
+        if (delay)
+                schedule_delayed_work(&cache_cleaner, delay);
+}
+
+
+/* 
+ * Clean all caches promptly.  This just calls cache_clean
+ * repeatedly until we are sure that every cache has had a chance to 
+ * be fully cleaned
+ */
+void cache_flush(void)
+{
+        while (cache_clean() != -1)
+                cond_resched();
+        while (cache_clean() != -1)
+                cond_resched();
+}
+
+void cache_purge(struct cache_detail *detail)
+{
+        detail->flush_time = LONG_MAX;
+        detail->nextcheck = get_seconds();
+        cache_flush();
+        detail->flush_time = 1;
+}
+
+
+
+/*
+ * Deferral and Revisiting of Requests.
+ *
+ * If a cache lookup finds a pending entry, we
+ * need to defer the request and revisit it later.
+ * All deferred requests are stored in a hash table,
+ * indexed by "struct cache_head *".
+ * As it may be wasteful to store a whole request
+ * structure, we allow the request to provide a 
+ * deferred form, which must contain a
+ * 'struct cache_deferred_req'
+ * This cache_deferred_req contains a method to allow
+ * it to be revisited when cache info is available
+ */
+
+#define DFR_HASHSIZE    (PAGE_SIZE/sizeof(struct list_head))
+#define DFR_HASH(item)  ((((long)item)>>4 ^ (((long)item)>>13)) % DFR_HASHSIZE)
+
+#define DFR_MAX 300     /* ??? */
+
+static DEFINE_SPINLOCK(cache_defer_lock);
+static LIST_HEAD(cache_defer_list);
+static struct list_head cache_defer_hash[DFR_HASHSIZE];
+static int cache_defer_cnt;
+
+static void cache_defer_req(struct cache_req *req, struct cache_head *item)
+{
+        struct cache_deferred_req *dreq;
+        int hash = DFR_HASH(item);
+
+        dreq = req->defer(req);
+        if (dreq == NULL)
+                return;
+
+        dreq->item = item;
+        dreq->recv_time = get_seconds();
+
+        spin_lock(&cache_defer_lock);
+
+        list_add(&dreq->recent, &cache_defer_list);
+
+        if (cache_defer_hash[hash].next == NULL)
+                INIT_LIST_HEAD(&cache_defer_hash[hash]);
+        list_add(&dreq->hash, &cache_defer_hash[hash]);
+
+        /* it is in, now maybe clean up */
+        dreq = NULL;
+        if (++cache_defer_cnt > DFR_MAX) {
+                /* too much in the cache, randomly drop
+                 * first or last
+                 */
+                if (net_random()&1) 
+                        dreq = list_entry(cache_defer_list.next,
+                                          struct cache_deferred_req,
+                                          recent);
+                else
+                        dreq = list_entry(cache_defer_list.prev,
+                                          struct cache_deferred_req,
+                                          recent);
+                list_del(&dreq->recent);
+                list_del(&dreq->hash);
+                cache_defer_cnt--;
+        }
+        spin_unlock(&cache_defer_lock);
+
+        if (dreq) {
+                /* there was one too many */
+                dreq->revisit(dreq, 1);
+        }
+        if (test_bit(CACHE_VALID, &item->flags)) {
+                /* must have just been validated... */
+                cache_revisit_request(item);
+        }
+}
+
+static void cache_revisit_request(struct cache_head *item)
+{
+        struct cache_deferred_req *dreq;
+        struct list_head pending;
+
+        struct list_head *lp;
+        int hash = DFR_HASH(item);
+
+        INIT_LIST_HEAD(&pending);
+        spin_lock(&cache_defer_lock);
+        
+        lp = cache_defer_hash[hash].next;
+        if (lp) {
+                while (lp != &cache_defer_hash[hash]) {
+                        dreq = list_entry(lp, struct cache_deferred_req, hash);
+                        lp = lp->next;
+                        if (dreq->item == item) {
+                                list_del(&dreq->hash);
+                                list_move(&dreq->recent, &pending);
+                                cache_defer_cnt--;
+                        }
+                }
+        }
+        spin_unlock(&cache_defer_lock);
+
+        while (!list_empty(&pending)) {
+                dreq = list_entry(pending.next, struct cache_deferred_req, recent);
+                list_del_init(&dreq->recent);
+                dreq->revisit(dreq, 0);
+        }
+}
+
+void cache_clean_deferred(void *owner)
+{
+        struct cache_deferred_req *dreq, *tmp;
+        struct list_head pending;
+
+
+        INIT_LIST_HEAD(&pending);
+        spin_lock(&cache_defer_lock);
+        
+        list_for_each_entry_safe(dreq, tmp, &cache_defer_list, recent) {
+                if (dreq->owner == owner) {
+                        list_del(&dreq->hash);
+                        list_move(&dreq->recent, &pending);
+                        cache_defer_cnt--;
+                }
+        }
+        spin_unlock(&cache_defer_lock);
+
+        while (!list_empty(&pending)) {
+                dreq = list_entry(pending.next, struct cache_deferred_req, recent);
+                list_del_init(&dreq->recent);
+                dreq->revisit(dreq, 1);
+        }
+}
+
+/*
+ * communicate with user-space
+ *
+ * We have a magic /proc file - /proc/sunrpc/cache
+ * On read, you get a full request, or block
+ * On write, an update request is processed
+ * Poll works if anything to read, and always allows write
+ *
+ * Implemented by linked list of requests.  Each open file has 
+ * a ->private that also exists in this list.  New request are added
+ * to the end and may wakeup and preceding readers.
+ * New readers are added to the head.  If, on read, an item is found with
+ * CACHE_UPCALLING clear, we free it from the list.
+ *
+ */
+
+static DEFINE_SPINLOCK(queue_lock);
+static DECLARE_MUTEX(queue_io_sem);
+
+struct cache_queue {
+        struct list_head        list;
+        int                     reader; /* if 0, then request */
+};
+struct cache_request {
+        struct cache_queue      q;
+        struct cache_head       *item;
+        char                    * buf;
+        int                     len;
+        int                     readers;
+};
+struct cache_reader {
+        struct cache_queue      q;
+        int                     offset; /* if non-0, we have a refcnt on next request */
+};
+
+static ssize_t
+cache_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos)
+{
+        struct cache_reader *rp = filp->private_data;
+        struct cache_request *rq;
+        struct cache_detail *cd = PDE(filp->f_dentry->d_inode)->data;
+        int err;
+
+        if (count == 0)
+                return 0;
+
+        down(&queue_io_sem); /* protect against multiple concurrent
+                              * readers on this file */
+ again:
+        spin_lock(&queue_lock);
+        /* need to find next request */
+        while (rp->q.list.next != &cd->queue &&
+               list_entry(rp->q.list.next, struct cache_queue, list)
+               ->reader) {
+                struct list_head *next = rp->q.list.next;
+                list_move(&rp->q.list, next);
+        }
+        if (rp->q.list.next == &cd->queue) {
+                spin_unlock(&queue_lock);
+                up(&queue_io_sem);
+                if (rp->offset)
+                        BUG();
+                return 0;
+        }
+        rq = container_of(rp->q.list.next, struct cache_request, q.list);
+        if (rq->q.reader) BUG();
+        if (rp->offset == 0)
+                rq->readers++;
+        spin_unlock(&queue_lock);
+
+        if (rp->offset == 0 && !test_bit(CACHE_PENDING, &rq->item->flags)) {
+                err = -EAGAIN;
+                spin_lock(&queue_lock);
+                list_move(&rp->q.list, &rq->q.list);
+                spin_unlock(&queue_lock);
+        } else {
+                if (rp->offset + count > rq->len)
+                        count = rq->len - rp->offset;
+                err = -EFAULT;
+                if (copy_to_user(buf, rq->buf + rp->offset, count))
+                        goto out;
+                rp->offset += count;
+                if (rp->offset >= rq->len) {
+                        rp->offset = 0;
+                        spin_lock(&queue_lock);
+                        list_move(&rp->q.list, &rq->q.list);
+                        spin_unlock(&queue_lock);
+                }
+                err = 0;
+        }
+ out:
+        if (rp->offset == 0) {
+                /* need to release rq */
+                spin_lock(&queue_lock);
+                rq->readers--;
+                if (rq->readers == 0 &&
+                    !test_bit(CACHE_PENDING, &rq->item->flags)) {
+                        list_del(&rq->q.list);
+                        spin_unlock(&queue_lock);
+                        cd->cache_put(rq->item, cd);
+                        kfree(rq->buf);
+                        kfree(rq);
+                } else
+                        spin_unlock(&queue_lock);
+        }
+        if (err == -EAGAIN)
+                goto again;
+        up(&queue_io_sem);
+        return err ? err :  count;
+}
+
+static char write_buf[8192]; /* protected by queue_io_sem */
+
+static ssize_t
+cache_write(struct file *filp, const char __user *buf, size_t count,
+            loff_t *ppos)
+{
+        int err;
+        struct cache_detail *cd = PDE(filp->f_dentry->d_inode)->data;
+
+        if (count == 0)
+                return 0;
+        if (count >= sizeof(write_buf))
+                return -EINVAL;
+
+        down(&queue_io_sem);
+
+        if (copy_from_user(write_buf, buf, count)) {
+                up(&queue_io_sem);
+                return -EFAULT;
+        }
+        write_buf[count] = '\0';
+        if (cd->cache_parse)
+                err = cd->cache_parse(cd, write_buf, count);
+        else
+                err = -EINVAL;
+
+        up(&queue_io_sem);
+        return err ? err : count;
+}
+
+static DECLARE_WAIT_QUEUE_HEAD(queue_wait);
+
+static unsigned int
+cache_poll(struct file *filp, poll_table *wait)
+{
+        unsigned int mask;
+        struct cache_reader *rp = filp->private_data;
+        struct cache_queue *cq;
+        struct cache_detail *cd = PDE(filp->f_dentry->d_inode)->data;
+
+        poll_wait(filp, &queue_wait, wait);
+
+        /* alway allow write */
+        mask = POLL_OUT | POLLWRNORM;
+
+        if (!rp)
+                return mask;
+
+        spin_lock(&queue_lock);
+
+        for (cq= &rp->q; &cq->list != &cd->queue;
+             cq = list_entry(cq->list.next, struct cache_queue, list))
+                if (!cq->reader) {
+                        mask |= POLLIN | POLLRDNORM;
+                        break;
+                }
+        spin_unlock(&queue_lock);
+        return mask;
+}
+
+static int
+cache_ioctl(struct inode *ino, struct file *filp,
+            unsigned int cmd, unsigned long arg)
+{
+        int len = 0;
+        struct cache_reader *rp = filp->private_data;
+        struct cache_queue *cq;
+        struct cache_detail *cd = PDE(ino)->data;
+
+        if (cmd != FIONREAD || !rp)
+                return -EINVAL;
+
+        spin_lock(&queue_lock);
+
+        /* only find the length remaining in current request,
+         * or the length of the next request
+         */
+        for (cq= &rp->q; &cq->list != &cd->queue;
+             cq = list_entry(cq->list.next, struct cache_queue, list))
+                if (!cq->reader) {
+                        struct cache_request *cr =
+                                container_of(cq, struct cache_request, q);
+                        len = cr->len - rp->offset;
+                        break;
+                }
+        spin_unlock(&queue_lock);
+
+        return put_user(len, (int __user *)arg);
+}
+
+static int
+cache_open(struct inode *inode, struct file *filp)
+{
+        struct cache_reader *rp = NULL;
+
+        nonseekable_open(inode, filp);
+        if (filp->f_mode & FMODE_READ) {
+                struct cache_detail *cd = PDE(inode)->data;
+
+                rp = kmalloc(sizeof(*rp), GFP_KERNEL);
+                if (!rp)
+                        return -ENOMEM;
+                rp->offset = 0;
+                rp->q.reader = 1;
+                atomic_inc(&cd->readers);
+                spin_lock(&queue_lock);
+                list_add(&rp->q.list, &cd->queue);
+                spin_unlock(&queue_lock);
+        }
+        filp->private_data = rp;
+        return 0;
+}
+
+static int
+cache_release(struct inode *inode, struct file *filp)
+{
+        struct cache_reader *rp = filp->private_data;
+        struct cache_detail *cd = PDE(inode)->data;
+
+        if (rp) {
+                spin_lock(&queue_lock);
+                if (rp->offset) {
+                        struct cache_queue *cq;
+                        for (cq= &rp->q; &cq->list != &cd->queue;
+                             cq = list_entry(cq->list.next, struct cache_queue, list))
+                                if (!cq->reader) {
+                                        container_of(cq, struct cache_request, q)
+                                                ->readers--;
+                                        break;
+                                }
+                        rp->offset = 0;
+                }
+                list_del(&rp->q.list);
+                spin_unlock(&queue_lock);
+
+                filp->private_data = NULL;
+                kfree(rp);
+
+                cd->last_close = get_seconds();
+                atomic_dec(&cd->readers);
+        }
+        return 0;
+}
+
+
+
+static struct file_operations cache_file_operations = {
+        .owner          = THIS_MODULE,
+        .llseek         = no_llseek,
+        .read           = cache_read,
+        .write          = cache_write,
+        .poll           = cache_poll,
+        .ioctl          = cache_ioctl, /* for FIONREAD */
+        .open           = cache_open,
+        .release        = cache_release,
+};
+
+
+static void queue_loose(struct cache_detail *detail, struct cache_head *ch)
+{
+        struct cache_queue *cq;
+        spin_lock(&queue_lock);
+        list_for_each_entry(cq, &detail->queue, list)
+                if (!cq->reader) {
+                        struct cache_request *cr = container_of(cq, struct cache_request, q);
+                        if (cr->item != ch)
+                                continue;
+                        if (cr->readers != 0)
+                                break;
+                        list_del(&cr->q.list);
+                        spin_unlock(&queue_lock);
+                        detail->cache_put(cr->item, detail);
+                        kfree(cr->buf);
+                        kfree(cr);
+                        return;
+                }
+        spin_unlock(&queue_lock);
+}
+
+/*
+ * Support routines for text-based upcalls.
+ * Fields are separated by spaces.
+ * Fields are either mangled to quote space tab newline slosh with slosh
+ * or a hexified with a leading \x
+ * Record is terminated with newline.
+ *
+ */
+
+void qword_add(char **bpp, int *lp, char *str)
+{
+        char *bp = *bpp;
+        int len = *lp;
+        char c;
+
+        if (len < 0) return;
+
+        while ((c=*str++) && len)
+                switch(c) {
+                case ' ':
+                case '\t':
+                case '\n':
+                case '\\':
+                        if (len >= 4) {
+                                *bp++ = '\\';
+                                *bp++ = '0' + ((c & 0300)>>6);
+                                *bp++ = '0' + ((c & 0070)>>3);
+                                *bp++ = '0' + ((c & 0007)>>0);
+                        }
+                        len -= 4;
+                        break;
+                default:
+                        *bp++ = c;
+                        len--;
+                }
+        if (c || len <1) len = -1;
+        else {
+                *bp++ = ' ';
+                len--;
+        }
+        *bpp = bp;
+        *lp = len;
+}
+
+void qword_addhex(char **bpp, int *lp, char *buf, int blen)
+{
+        char *bp = *bpp;
+        int len = *lp;
+
+        if (len < 0) return;
+
+        if (len > 2) {
+                *bp++ = '\\';
+                *bp++ = 'x';
+                len -= 2;
+                while (blen && len >= 2) {
+                        unsigned char c = *buf++;
+                        *bp++ = '0' + ((c&0xf0)>>4) + (c>=0xa0)*('a'-'9'-1);
+                        *bp++ = '0' + (c&0x0f) + ((c&0x0f)>=0x0a)*('a'-'9'-1);
+                        len -= 2;
+                        blen--;
+                }
+        }
+        if (blen || len<1) len = -1;
+        else {
+                *bp++ = ' ';
+                len--;
+        }
+        *bpp = bp;
+        *lp = len;
+}
+
+static void warn_no_listener(struct cache_detail *detail)
+{
+        if (detail->last_warn != detail->last_close) {
+                detail->last_warn = detail->last_close;
+                if (detail->warn_no_listener)
+                        detail->warn_no_listener(detail);
+        }
+}
+
+/*
+ * register an upcall request to user-space.
+ * Each request is at most one page long.
+ */
+static int cache_make_upcall(struct cache_detail *detail, struct cache_head *h)
+{
+
+        char *buf;
+        struct cache_request *crq;
+        char *bp;
+        int len;
+
+        if (detail->cache_request == NULL)
+                return -EINVAL;
+
+        if (atomic_read(&detail->readers) == 0 &&
+            detail->last_close < get_seconds() - 30) {
+                        warn_no_listener(detail);
+                        return -EINVAL;
+        }
+
+        buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
+        if (!buf)
+                return -EAGAIN;
+
+        crq = kmalloc(sizeof (*crq), GFP_KERNEL);
+        if (!crq) {
+                kfree(buf);
+                return -EAGAIN;
+        }
+
+        bp = buf; len = PAGE_SIZE;
+
+        detail->cache_request(detail, h, &bp, &len);
+
+        if (len < 0) {
+                kfree(buf);
+                kfree(crq);
+                return -EAGAIN;
+        }
+        crq->q.reader = 0;
+        crq->item = cache_get(h);
+        crq->buf = buf;
+        crq->len = PAGE_SIZE - len;
+        crq->readers = 0;
+        spin_lock(&queue_lock);
+        list_add_tail(&crq->q.list, &detail->queue);
+        spin_unlock(&queue_lock);
+        wake_up(&queue_wait);
+        return 0;
+}
+
+/*
+ * parse a message from user-space and pass it
+ * to an appropriate cache
+ * Messages are, like requests, separated into fields by
+ * spaces and dequotes as \xHEXSTRING or embedded \nnn octal
+ *
+ * Message is 
+ *   reply cachename expiry key ... content....
+ *
+ * key and content are both parsed by cache 
+ */
+
+#define isodigit(c) (isdigit(c) && c <= '7')
+int qword_get(char **bpp, char *dest, int bufsize)
+{
+        /* return bytes copied, or -1 on error */
+        char *bp = *bpp;
+        int len = 0;
+
+        while (*bp == ' ') bp++;
+
+        if (bp[0] == '\\' && bp[1] == 'x') {
+                /* HEX STRING */
+                bp += 2;
+                while (isxdigit(bp[0]) && isxdigit(bp[1]) && len < bufsize) {
+                        int byte = isdigit(*bp) ? *bp-'0' : toupper(*bp)-'A'+10;
+                        bp++;
+                        byte <<= 4;
+                        byte |= isdigit(*bp) ? *bp-'0' : toupper(*bp)-'A'+10;
+                        *dest++ = byte;
+                        bp++;
+                        len++;
+                }
+        } else {
+                /* text with \nnn octal quoting */
+                while (*bp != ' ' && *bp != '\n' && *bp && len < bufsize-1) {
+                        if (*bp == '\\' &&
+                            isodigit(bp[1]) && (bp[1] <= '3') &&
+                            isodigit(bp[2]) &&
+                            isodigit(bp[3])) {
+                                int byte = (*++bp -'0');
+                                bp++;
+                                byte = (byte << 3) | (*bp++ - '0');
+                                byte = (byte << 3) | (*bp++ - '0');
+                                *dest++ = byte;
+                                len++;
+                        } else {
+                                *dest++ = *bp++;
+                                len++;
+                        }
+                }
+        }
+
+        if (*bp != ' ' && *bp != '\n' && *bp != '\0')
+                return -1;
+        while (*bp == ' ') bp++;
+        *bpp = bp;
+        *dest = '\0';
+        return len;
+}
+
+
+/*
+ * support /proc/sunrpc/cache/$CACHENAME/content
+ * as a seqfile.
+ * We call ->cache_show passing NULL for the item to
+ * get a header, then pass each real item in the cache
+ */
+
+struct handle {
+        struct cache_detail *cd;
+};
+
+static void *c_start(struct seq_file *m, loff_t *pos)
+{
+        loff_t n = *pos;
+        unsigned hash, entry;
+        struct cache_head *ch;
+        struct cache_detail *cd = ((struct handle*)m->private)->cd;
+        
+
+        read_lock(&cd->hash_lock);
+        if (!n--)
+                return SEQ_START_TOKEN;
+        hash = n >> 32;
+        entry = n & ((1LL<<32) - 1);
+
+        for (ch=cd->hash_table[hash]; ch; ch=ch->next)
+                if (!entry--)
+                        return ch;
+        n &= ~((1LL<<32) - 1);
+        do {
+                hash++;
+                n += 1LL<<32;
+        } while(hash < cd->hash_size && 
+                cd->hash_table[hash]==NULL);
+        if (hash >= cd->hash_size)
+                return NULL;
+        *pos = n+1;
+        return cd->hash_table[hash];
+}
+
+static void *c_next(struct seq_file *m, void *p, loff_t *pos)
+{
+        struct cache_head *ch = p;
+        int hash = (*pos >> 32);
+        struct cache_detail *cd = ((struct handle*)m->private)->cd;
+
+        if (p == SEQ_START_TOKEN)
+                hash = 0;
+        else if (ch->next == NULL) {
+                hash++;
+                *pos += 1LL<<32;
+        } else {
+                ++*pos;
+                return ch->next;
+        }
+        *pos &= ~((1LL<<32) - 1);
+        while (hash < cd->hash_size &&
+               cd->hash_table[hash] == NULL) {
+                hash++;
+                *pos += 1LL<<32;
+        }
+        if (hash >= cd->hash_size)
+                return NULL;
+        ++*pos;
+        return cd->hash_table[hash];
+}
+
+static void c_stop(struct seq_file *m, void *p)
+{
+        struct cache_detail *cd = ((struct handle*)m->private)->cd;
+        read_unlock(&cd->hash_lock);
+}
+
+static int c_show(struct seq_file *m, void *p)
+{
+        struct cache_head *cp = p;
+        struct cache_detail *cd = ((struct handle*)m->private)->cd;
+
+        if (p == SEQ_START_TOKEN)
+                return cd->cache_show(m, cd, NULL);
+
+        ifdebug(CACHE)
+                seq_printf(m, "# expiry=%ld refcnt=%d\n",
+                           cp->expiry_time, atomic_read(&cp->refcnt));
+        cache_get(cp);
+        if (cache_check(cd, cp, NULL))
+                /* cache_check does a cache_put on failure */
+                seq_printf(m, "# ");
+        else
+                cache_put(cp, cd);
+
+        return cd->cache_show(m, cd, cp);
+}
+
+static struct seq_operations cache_content_op = {
+        .start  = c_start,
+        .next   = c_next,
+        .stop   = c_stop,
+        .show   = c_show,
+};
+
+static int content_open(struct inode *inode, struct file *file)
+{
+        int res;
+        struct handle *han;
+        struct cache_detail *cd = PDE(inode)->data;
+
+        han = kmalloc(sizeof(*han), GFP_KERNEL);
+        if (han == NULL)
+                return -ENOMEM;
+
+        han->cd = cd;
+
+        res = seq_open(file, &cache_content_op);
+        if (res)
+                kfree(han);
+        else
+                ((struct seq_file *)file->private_data)->private = han;
+
+        return res;
+}
+static int content_release(struct inode *inode, struct file *file)
+{
+        struct seq_file *m = (struct seq_file *)file->private_data;
+        struct handle *han = m->private;
+        kfree(han);
+        m->private = NULL;
+        return seq_release(inode, file);
+}
+
+static struct file_operations content_file_operations = {
+        .open           = content_open,
+        .read           = seq_read,
+        .llseek         = seq_lseek,
+        .release        = content_release,
+};
+
+static ssize_t read_flush(struct file *file, char __user *buf,
+                            size_t count, loff_t *ppos)
+{
+        struct cache_detail *cd = PDE(file->f_dentry->d_inode)->data;
+        char tbuf[20];
+        unsigned long p = *ppos;
+        int len;
+
+        sprintf(tbuf, "%lu\n", cd->flush_time);
+        len = strlen(tbuf);
+        if (p >= len)
+                return 0;
+        len -= p;
+        if (len > count) len = count;
+        if (copy_to_user(buf, (void*)(tbuf+p), len))
+                len = -EFAULT;
+        else
+                *ppos += len;
+        return len;
+}
+
+static ssize_t write_flush(struct file * file, const char __user * buf,
+                             size_t count, loff_t *ppos)
+{
+        struct cache_detail *cd = PDE(file->f_dentry->d_inode)->data;
+        char tbuf[20];
+        char *ep;
+        long flushtime;
+        if (*ppos || count > sizeof(tbuf)-1)
+                return -EINVAL;
+        if (copy_from_user(tbuf, buf, count))
+                return -EFAULT;
+        tbuf[count] = 0;
+        flushtime = simple_strtoul(tbuf, &ep, 0);
+        if (*ep && *ep != '\n')
+                return -EINVAL;
+
+        cd->flush_time = flushtime;
+        cd->nextcheck = get_seconds();
+        cache_flush();
+
+        *ppos += count;
+        return count;
+}
+
+static struct file_operations cache_flush_operations = {
+        .open           = nonseekable_open,
+        .read           = read_flush,
+        .write          = write_flush,
+};