Merge with /pub/scm/linux/kernel/git/torvalds/linux-2.6.git

Signed-off-by: Steve French <sfrench@us.ibm.com>

1 files changed, 145 insertions, 35 deletions

diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
index dcaa0c4453ff..3ac4193a78ed 100644
--- a/net/sunrpc/cache.c
+++ b/net/sunrpc/cache.c
@@ -26,6 +26,7 @@
 #include <linux/proc_fs.h>
 #include <linux/net.h>
 #include <linux/workqueue.h>
+#include <linux/mutex.h>
 #include <asm/ioctls.h>
 #include <linux/sunrpc/types.h>
 #include <linux/sunrpc/cache.h>
@@ -36,16 +37,138 @@
 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)
+static void cache_init(struct cache_head *h)
 {
         time_t now = get_seconds();
         h->next = NULL;
         h->flags = 0;
-        atomic_set(&h->refcnt, 1);
+        kref_init(&h->ref);
         h->expiry_time = now + CACHE_NEW_EXPIRY;
         h->last_refresh = now;
 }
 
+struct cache_head *sunrpc_cache_lookup(struct cache_detail *detail,
+                                       struct cache_head *key, int hash)
+{
+        struct cache_head **head,  **hp;
+        struct cache_head *new = NULL;
+
+        head = &detail->hash_table[hash];
+
+        read_lock(&detail->hash_lock);
+
+        for (hp=head; *hp != NULL ; hp = &(*hp)->next) {
+                struct cache_head *tmp = *hp;
+                if (detail->match(tmp, key)) {
+                        cache_get(tmp);
+                        read_unlock(&detail->hash_lock);
+                        return tmp;
+                }
+        }
+        read_unlock(&detail->hash_lock);
+        /* Didn't find anything, insert an empty entry */
+
+        new = detail->alloc();
+        if (!new)
+                return NULL;
+        cache_init(new);
+
+        write_lock(&detail->hash_lock);
+
+        /* check if entry appeared while we slept */
+        for (hp=head; *hp != NULL ; hp = &(*hp)->next) {
+                struct cache_head *tmp = *hp;
+                if (detail->match(tmp, key)) {
+                        cache_get(tmp);
+                        write_unlock(&detail->hash_lock);
+                        cache_put(new, detail);
+                        return tmp;
+                }
+        }
+        detail->init(new, key);
+        new->next = *head;
+        *head = new;
+        detail->entries++;
+        cache_get(new);
+        write_unlock(&detail->hash_lock);
+
+        return new;
+}
+EXPORT_SYMBOL(sunrpc_cache_lookup);
+
+
+static void queue_loose(struct cache_detail *detail, struct cache_head *ch);
+
+static int cache_fresh_locked(struct cache_head *head, time_t expiry)
+{
+        head->expiry_time = expiry;
+        head->last_refresh = get_seconds();
+        return !test_and_set_bit(CACHE_VALID, &head->flags);
+}
+
+static void cache_fresh_unlocked(struct cache_head *head,
+                        struct cache_detail *detail, int new)
+{
+        if (new)
+                cache_revisit_request(head);
+        if (test_and_clear_bit(CACHE_PENDING, &head->flags)) {
+                cache_revisit_request(head);
+                queue_loose(detail, head);
+        }
+}
+
+struct cache_head *sunrpc_cache_update(struct cache_detail *detail,
+                                       struct cache_head *new, struct cache_head *old, int hash)
+{
+        /* The 'old' entry is to be replaced by 'new'.
+         * If 'old' is not VALID, we update it directly,
+         * otherwise we need to replace it
+         */
+        struct cache_head **head;
+        struct cache_head *tmp;
+        int is_new;
+
+        if (!test_bit(CACHE_VALID, &old->flags)) {
+                write_lock(&detail->hash_lock);
+                if (!test_bit(CACHE_VALID, &old->flags)) {
+                        if (test_bit(CACHE_NEGATIVE, &new->flags))
+                                set_bit(CACHE_NEGATIVE, &old->flags);
+                        else
+                                detail->update(old, new);
+                        is_new = cache_fresh_locked(old, new->expiry_time);
+                        write_unlock(&detail->hash_lock);
+                        cache_fresh_unlocked(old, detail, is_new);
+                        return old;
+                }
+                write_unlock(&detail->hash_lock);
+        }
+        /* We need to insert a new entry */
+        tmp = detail->alloc();
+        if (!tmp) {
+                cache_put(old, detail);
+                return NULL;
+        }
+        cache_init(tmp);
+        detail->init(tmp, old);
+        head = &detail->hash_table[hash];
+
+        write_lock(&detail->hash_lock);
+        if (test_bit(CACHE_NEGATIVE, &new->flags))
+                set_bit(CACHE_NEGATIVE, &tmp->flags);
+        else
+                detail->update(tmp, new);
+        tmp->next = *head;
+        *head = tmp;
+        cache_get(tmp);
+        is_new = cache_fresh_locked(tmp, new->expiry_time);
+        cache_fresh_locked(old, 0);
+        write_unlock(&detail->hash_lock);
+        cache_fresh_unlocked(tmp, detail, is_new);
+        cache_fresh_unlocked(old, detail, 0);
+        cache_put(old, detail);
+        return tmp;
+}
+EXPORT_SYMBOL(sunrpc_cache_update);
 
 static int cache_make_upcall(struct cache_detail *detail, struct cache_head *h);
 /*
@@ -93,7 +216,8 @@ int cache_check(struct cache_detail *detail,
                                 clear_bit(CACHE_PENDING, &h->flags);
                                 if (rv == -EAGAIN) {
                                         set_bit(CACHE_NEGATIVE, &h->flags);
-                                        cache_fresh(detail, h, get_seconds()+CACHE_NEW_EXPIRY);
+                                        cache_fresh_unlocked(h, detail,
+                                             cache_fresh_locked(h, get_seconds()+CACHE_NEW_EXPIRY));
                                         rv = -ENOENT;
                                 }
                                 break;
@@ -109,25 +233,11 @@ int cache_check(struct cache_detail *detail,
         if (rv == -EAGAIN)
                 cache_defer_req(rqstp, h);
 
-        if (rv && h)
-                detail->cache_put(h, detail);
+        if (rv)
+                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
@@ -321,7 +431,7 @@ static int cache_clean(void)
                         if (test_and_clear_bit(CACHE_PENDING, &ch->flags))
                                 queue_loose(current_detail, ch);
 
-                        if (atomic_read(&ch->refcnt) == 1)
+                        if (atomic_read(&ch->ref.refcount) == 1)
                                 break;
                 }
                 if (ch) {
@@ -336,7 +446,7 @@ static int cache_clean(void)
                         current_index ++;
                 spin_unlock(&cache_list_lock);
                 if (ch)
-                        d->cache_put(ch, d);
+                        cache_put(ch, d);
         } else
                 spin_unlock(&cache_list_lock);
 
@@ -452,7 +562,7 @@ static void cache_defer_req(struct cache_req *req, struct cache_head *item)
                 /* there was one too many */
                 dreq->revisit(dreq, 1);
         }
-        if (test_bit(CACHE_VALID, &item->flags)) {
+        if (!test_bit(CACHE_PENDING, &item->flags)) {
                 /* must have just been validated... */
                 cache_revisit_request(item);
         }
@@ -532,7 +642,7 @@ void cache_clean_deferred(void *owner)
  */
 
 static DEFINE_SPINLOCK(queue_lock);
-static DECLARE_MUTEX(queue_io_sem);
+static DEFINE_MUTEX(queue_io_mutex);
 
 struct cache_queue {
         struct list_head        list;
@@ -561,7 +671,7 @@ cache_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos)
         if (count == 0)
                 return 0;
 
-        down(&queue_io_sem); /* protect against multiple concurrent
+        mutex_lock(&queue_io_mutex); /* protect against multiple concurrent
                               * readers on this file */
  again:
         spin_lock(&queue_lock);
@@ -574,7 +684,7 @@ cache_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos)
         }
         if (rp->q.list.next == &cd->queue) {
                 spin_unlock(&queue_lock);
-                up(&queue_io_sem);
+                mutex_unlock(&queue_io_mutex);
                 BUG_ON(rp->offset);
                 return 0;
         }
@@ -613,7 +723,7 @@ cache_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos)
                     !test_bit(CACHE_PENDING, &rq->item->flags)) {
                         list_del(&rq->q.list);
                         spin_unlock(&queue_lock);
-                        cd->cache_put(rq->item, cd);
+                        cache_put(rq->item, cd);
                         kfree(rq->buf);
                         kfree(rq);
                 } else
@@ -621,11 +731,11 @@ cache_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos)
         }
         if (err == -EAGAIN)
                 goto again;
-        up(&queue_io_sem);
+        mutex_unlock(&queue_io_mutex);
         return err ? err :  count;
 }
 
-static char write_buf[8192]; /* protected by queue_io_sem */
+static char write_buf[8192]; /* protected by queue_io_mutex */
 
 static ssize_t
 cache_write(struct file *filp, const char __user *buf, size_t count,
@@ -639,10 +749,10 @@ cache_write(struct file *filp, const char __user *buf, size_t count,
         if (count >= sizeof(write_buf))
                 return -EINVAL;
 
-        down(&queue_io_sem);
+        mutex_lock(&queue_io_mutex);
 
         if (copy_from_user(write_buf, buf, count)) {
-                up(&queue_io_sem);
+                mutex_unlock(&queue_io_mutex);
                 return -EFAULT;
         }
         write_buf[count] = '\0';
@@ -651,7 +761,7 @@ cache_write(struct file *filp, const char __user *buf, size_t count,
         else
                 err = -EINVAL;
 
-        up(&queue_io_sem);
+        mutex_unlock(&queue_io_mutex);
         return err ? err : count;
 }
 
@@ -793,10 +903,10 @@ static void queue_loose(struct cache_detail *detail, struct cache_head *ch)
                         if (cr->item != ch)
                                 continue;
                         if (cr->readers != 0)
-                                break;
+                                continue;
                         list_del(&cr->q.list);
                         spin_unlock(&queue_lock);
-                        detail->cache_put(cr->item, detail);
+                        cache_put(cr->item, detail);
                         kfree(cr->buf);
                         kfree(cr);
                         return;
@@ -1081,8 +1191,8 @@ static int c_show(struct seq_file *m, void *p)
                 return cd->cache_show(m, cd, NULL);
 
         ifdebug(CACHE)
-                seq_printf(m, "# expiry=%ld refcnt=%d\n",
-                           cp->expiry_time, atomic_read(&cp->refcnt));
+                seq_printf(m, "# expiry=%ld refcnt=%d flags=%lx\n",
+                           cp->expiry_time, atomic_read(&cp->ref.refcount), cp->flags);
         cache_get(cp);
         if (cache_check(cd, cp, NULL))
                 /* cache_check does a cache_put on failure */