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-rw-r--r--net/sunrpc/cache.c163
1 files changed, 136 insertions, 27 deletions
diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
index 0acccfeeb28..3ac4193a78e 100644
--- a/net/sunrpc/cache.c
+++ b/net/sunrpc/cache.c
@@ -37,16 +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);
/*
@@ -94,7 +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;
@@ -110,25 +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
@@ -322,7 +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) {
@@ -337,7 +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);
@@ -453,7 +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);
}
@@ -614,7 +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
@@ -794,10 +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;
@@ -1082,8 +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 */
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-12-27 07:48:57 +0000