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Commit 11174492 authored by NeilBrown's avatar NeilBrown Committed by J. Bruce Fields
Browse files

sunrpc/cache: change deferred-request hash table to use hlist. 



Being a hash table, hlist is the best option.

There is currently some ugliness were we treat "->next == NULL" as
a special case to avoid having to initialise the whole array.
This change nicely gets rid of that case.

Signed-off-by: default avatarNeilBrown <neilb@suse.de>
Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
parent 2ed5282c

include/linux/sunrpc/cache.h

+1 −1
Original line number Diff line number Diff line
@@ -133,7 +133,7 @@ struct cache_req { 
 * delayed awaiting cache-fill

 */

struct cache_deferred_req {

	struct list_head	hash;	/* on hash chain */

	struct hlist_node	hash;	/* on hash chain */

	struct list_head	recent; /* on fifo */

	struct cache_head	*item;  /* cache item we wait on */

	void			*owner; /* we might need to discard all defered requests

net/sunrpc/cache.c

+10 −18
Original line number Diff line number Diff line
@@ -506,13 +506,13 @@ EXPORT_SYMBOL_GPL(cache_purge); 


static DEFINE_SPINLOCK(cache_defer_lock);

static LIST_HEAD(cache_defer_list);

static struct list_head cache_defer_hash[DFR_HASHSIZE];

static struct hlist_head cache_defer_hash[DFR_HASHSIZE];

static int cache_defer_cnt;



static void __unhash_deferred_req(struct cache_deferred_req *dreq)

{

	list_del_init(&dreq->recent);

	list_del_init(&dreq->hash);

	hlist_del_init(&dreq->hash);

	cache_defer_cnt--;

}
@@ -521,9 +521,7 @@ static void __hash_deferred_req(struct cache_deferred_req *dreq, struct cache_he 
	int hash = DFR_HASH(item);



	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]);

	hlist_add_head(&dreq->hash, &cache_defer_hash[hash]);

}



static int setup_deferral(struct cache_deferred_req *dreq, struct cache_head *item)
@@ -588,7 +586,7 @@ static int cache_wait_req(struct cache_req *req, struct cache_head *item) 
		 * to clean up

		 */

		spin_lock(&cache_defer_lock);

		if (!list_empty(&sleeper.handle.hash)) {

		if (!hlist_unhashed(&sleeper.handle.hash)) {

			__unhash_deferred_req(&sleeper.handle);

			spin_unlock(&cache_defer_lock);

		} else {
@@ -642,24 +640,18 @@ static void cache_revisit_request(struct cache_head *item) 
{

	struct cache_deferred_req *dreq;

	struct list_head pending;



	struct list_head *lp;

	struct hlist_node *lp, *tmp;

	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;

	hlist_for_each_entry_safe(dreq, lp, tmp, &cache_defer_hash[hash], hash)

		if (dreq->item == item) {

			__unhash_deferred_req(dreq);

			list_add(&dreq->recent, &pending);

		}

		}

	}



	spin_unlock(&cache_defer_lock);



	while (!list_empty(&pending)) {