On Mon, 27 Jul 2015 11:10:15 +0800 Kinglong Mee <kinglongmee@xxxxxxxxx>
wrote:
> Switch using list_head for cache_head in cache_detail,
> it is useful of remove an cache_head entry directly from cache_detail.
>
> v8, using hash list, not head list
>
> Signed-off-by: Kinglong Mee <kinglongmee@xxxxxxxxx>
Reviewed-by: NeilBrown <neilb@xxxxxxxx>
Thanks,
NeilBrown
> ---
> include/linux/sunrpc/cache.h | 4 +--
> net/sunrpc/cache.c | 60 +++++++++++++++++++++++---------------------
> 2 files changed, 33 insertions(+), 31 deletions(-)
>
> diff --git a/include/linux/sunrpc/cache.h b/include/linux/sunrpc/cache.h
> index 04ee5a2..03d3b4c 100644
> --- a/include/linux/sunrpc/cache.h
> +++ b/include/linux/sunrpc/cache.h
> @@ -46,7 +46,7 @@
> *
> */
> struct cache_head {
> - struct cache_head * next;
> + struct hlist_node cache_list;
> time_t expiry_time; /* After time time, don't use the data */
> time_t last_refresh; /* If CACHE_PENDING, this is when upcall
> * was sent, else this is when update was received
> @@ -73,7 +73,7 @@ struct cache_detail_pipefs {
> struct cache_detail {
> struct module * owner;
> int hash_size;
> - struct cache_head ** hash_table;
> + struct hlist_head * hash_table;
> rwlock_t hash_lock;
>
> atomic_t inuse; /* active user-space update or lookup */
> diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
> index 673c2fa..4a2340a 100644
> --- a/net/sunrpc/cache.c
> +++ b/net/sunrpc/cache.c
> @@ -44,7 +44,7 @@ static void cache_revisit_request(struct cache_head *item);
> static void cache_init(struct cache_head *h)
> {
> time_t now = seconds_since_boot();
> - h->next = NULL;
> + INIT_HLIST_NODE(&h->cache_list);
> h->flags = 0;
> kref_init(&h->ref);
> h->expiry_time = now + CACHE_NEW_EXPIRY;
> @@ -54,15 +54,14 @@ static void cache_init(struct cache_head *h)
> 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, *freeme = NULL;
> + struct cache_head *new = NULL, *freeme = NULL, *tmp = NULL;
> + struct hlist_head *head;
>
> head = &detail->hash_table[hash];
>
> read_lock(&detail->hash_lock);
>
> - for (hp=head; *hp != NULL ; hp = &(*hp)->next) {
> - struct cache_head *tmp = *hp;
> + hlist_for_each_entry(tmp, head, cache_list) {
> if (detail->match(tmp, key)) {
> if (cache_is_expired(detail, tmp))
> /* This entry is expired, we will discard it. */
> @@ -88,12 +87,10 @@ struct cache_head *sunrpc_cache_lookup(struct cache_detail *detail,
> 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;
> + hlist_for_each_entry(tmp, head, cache_list) {
> if (detail->match(tmp, key)) {
> if (cache_is_expired(detail, tmp)) {
> - *hp = tmp->next;
> - tmp->next = NULL;
> + hlist_del_init(&tmp->cache_list);
> detail->entries --;
> freeme = tmp;
> break;
> @@ -104,8 +101,8 @@ struct cache_head *sunrpc_cache_lookup(struct cache_detail *detail,
> return tmp;
> }
> }
> - new->next = *head;
> - *head = new;
> +
> + hlist_add_head(&new->cache_list, head);
> detail->entries++;
> cache_get(new);
> write_unlock(&detail->hash_lock);
> @@ -143,7 +140,6 @@ struct cache_head *sunrpc_cache_update(struct cache_detail *detail,
> * If 'old' is not VALID, we update it directly,
> * otherwise we need to replace it
> */
> - struct cache_head **head;
> struct cache_head *tmp;
>
> if (!test_bit(CACHE_VALID, &old->flags)) {
> @@ -168,15 +164,13 @@ struct cache_head *sunrpc_cache_update(struct cache_detail *detail,
> }
> 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;
> + hlist_add_head(&tmp->cache_list, &detail->hash_table[hash]);
> detail->entries++;
> cache_get(tmp);
> cache_fresh_locked(tmp, new->expiry_time);
> @@ -416,28 +410,29 @@ static int cache_clean(void)
> /* find a non-empty bucket in the table */
> while (current_detail &&
> current_index < current_detail->hash_size &&
> - current_detail->hash_table[current_index] == NULL)
> + hlist_empty(¤t_detail->hash_table[current_index]))
> 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_head *ch = NULL;
> struct cache_detail *d;
> + struct hlist_head *head;
> + struct hlist_node *tmp;
>
> write_lock(¤t_detail->hash_lock);
>
> /* Ok, now to clean this strand */
>
> - cp = & current_detail->hash_table[current_index];
> - for (ch = *cp ; ch ; cp = & ch->next, ch = *cp) {
> + head = ¤t_detail->hash_table[current_index];
> + hlist_for_each_entry_safe(ch, tmp, head, cache_list) {
> if (current_detail->nextcheck > ch->expiry_time)
> current_detail->nextcheck = ch->expiry_time+1;
> if (!cache_is_expired(current_detail, ch))
> continue;
>
> - *cp = ch->next;
> - ch->next = NULL;
> + hlist_del_init(&ch->cache_list);
> current_detail->entries--;
> rv = 1;
> break;
> @@ -1284,7 +1279,7 @@ void *cache_seq_start(struct seq_file *m, loff_t *pos)
> hash = n >> 32;
> entry = n & ((1LL<<32) - 1);
>
> - for (ch=cd->hash_table[hash]; ch; ch=ch->next)
> + hlist_for_each_entry(ch, &cd->hash_table[hash], cache_list)
> if (!entry--)
> return ch;
> n &= ~((1LL<<32) - 1);
> @@ -1292,11 +1287,12 @@ void *cache_seq_start(struct seq_file *m, loff_t *pos)
> hash++;
> n += 1LL<<32;
> } while(hash < cd->hash_size &&
> - cd->hash_table[hash]==NULL);
> + hlist_empty(&cd->hash_table[hash]));
> if (hash >= cd->hash_size)
> return NULL;
> *pos = n+1;
> - return cd->hash_table[hash];
> + return hlist_entry_safe(cd->hash_table[hash].first,
> + struct cache_head, cache_list);
> }
> EXPORT_SYMBOL_GPL(cache_seq_start);
>
> @@ -1308,23 +1304,25 @@ void *cache_seq_next(struct seq_file *m, void *p, loff_t *pos)
>
> if (p == SEQ_START_TOKEN)
> hash = 0;
> - else if (ch->next == NULL) {
> + else if (ch->cache_list.next == NULL) {
> hash++;
> *pos += 1LL<<32;
> } else {
> ++*pos;
> - return ch->next;
> + return hlist_entry_safe(ch->cache_list.next,
> + struct cache_head, cache_list);
> }
> *pos &= ~((1LL<<32) - 1);
> while (hash < cd->hash_size &&
> - cd->hash_table[hash] == NULL) {
> + hlist_empty(&cd->hash_table[hash])) {
> hash++;
> *pos += 1LL<<32;
> }
> if (hash >= cd->hash_size)
> return NULL;
> ++*pos;
> - return cd->hash_table[hash];
> + return hlist_entry_safe(cd->hash_table[hash].first,
> + struct cache_head, cache_list);
> }
> EXPORT_SYMBOL_GPL(cache_seq_next);
>
> @@ -1666,17 +1664,21 @@ EXPORT_SYMBOL_GPL(cache_unregister_net);
> struct cache_detail *cache_create_net(struct cache_detail *tmpl, struct net *net)
> {
> struct cache_detail *cd;
> + int i;
>
> cd = kmemdup(tmpl, sizeof(struct cache_detail), GFP_KERNEL);
> if (cd == NULL)
> return ERR_PTR(-ENOMEM);
>
> - cd->hash_table = kzalloc(cd->hash_size * sizeof(struct cache_head *),
> + cd->hash_table = kzalloc(cd->hash_size * sizeof(struct hlist_head),
> GFP_KERNEL);
> if (cd->hash_table == NULL) {
> kfree(cd);
> return ERR_PTR(-ENOMEM);
> }
> +
> + for (i = 0; i < cd->hash_size; i++)
> + INIT_HLIST_HEAD(&cd->hash_table[i]);
> cd->net = net;
> return cd;
> }
--
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