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Commit 1863d77f authored by Trond Myklebust's avatar Trond Myklebust Committed by J. Bruce Fields
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SUNRPC: Replace the cache_detail->hash_lock with a regular spinlock 



Now that the reader functions are all RCU protected, use a regular
spinlock rather than a reader/writer lock.

Signed-off-by: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
parent d48cf356

include/linux/sunrpc/cache.h

+1 −1
Original line number Diff line number Diff line
@@ -67,7 +67,7 @@ struct cache_detail { 
	struct module *		owner;

	int			hash_size;

	struct hlist_head *	hash_table;

	rwlock_t		hash_lock;

	spinlock_t		hash_lock;



	char			*name;

	void			(*cache_put)(struct kref *);

net/sunrpc/cache.c

+23 −23
Original line number Diff line number Diff line
@@ -92,7 +92,7 @@ static struct cache_head *sunrpc_cache_add_entry(struct cache_detail *detail, 
	cache_init(new, detail);

	detail->init(new, key);



	write_lock(&detail->hash_lock);

	spin_lock(&detail->hash_lock);



	/* check if entry appeared while we slept */

	hlist_for_each_entry_rcu(tmp, head, cache_list) {
@@ -104,7 +104,7 @@ static struct cache_head *sunrpc_cache_add_entry(struct cache_detail *detail, 
				break;

			}

			cache_get(tmp);

			write_unlock(&detail->hash_lock);

			spin_unlock(&detail->hash_lock);

			cache_put(new, detail);

			return tmp;

		}
@@ -113,7 +113,7 @@ static struct cache_head *sunrpc_cache_add_entry(struct cache_detail *detail, 
	hlist_add_head_rcu(&new->cache_list, head);

	detail->entries++;

	cache_get(new);

	write_unlock(&detail->hash_lock);

	spin_unlock(&detail->hash_lock);



	if (freeme)

		cache_put(freeme, detail);
@@ -167,18 +167,18 @@ struct cache_head *sunrpc_cache_update(struct cache_detail *detail, 
	struct cache_head *tmp;



	if (!test_bit(CACHE_VALID, &old->flags)) {

		write_lock(&detail->hash_lock);

		spin_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);

			cache_fresh_locked(old, new->expiry_time, detail);

			write_unlock(&detail->hash_lock);

			spin_unlock(&detail->hash_lock);

			cache_fresh_unlocked(old, detail);

			return old;

		}

		write_unlock(&detail->hash_lock);

		spin_unlock(&detail->hash_lock);

	}

	/* We need to insert a new entry */

	tmp = detail->alloc();
@@ -189,7 +189,7 @@ struct cache_head *sunrpc_cache_update(struct cache_detail *detail, 
	cache_init(tmp, detail);

	detail->init(tmp, old);



	write_lock(&detail->hash_lock);

	spin_lock(&detail->hash_lock);

	if (test_bit(CACHE_NEGATIVE, &new->flags))

		set_bit(CACHE_NEGATIVE, &tmp->flags);

	else
@@ -199,7 +199,7 @@ struct cache_head *sunrpc_cache_update(struct cache_detail *detail, 
	cache_get(tmp);

	cache_fresh_locked(tmp, new->expiry_time, detail);

	cache_fresh_locked(old, 0, detail);

	write_unlock(&detail->hash_lock);

	spin_unlock(&detail->hash_lock);

	cache_fresh_unlocked(tmp, detail);

	cache_fresh_unlocked(old, detail);

	cache_put(old, detail);
@@ -239,7 +239,7 @@ static int try_to_negate_entry(struct cache_detail *detail, struct cache_head *h 
{

	int rv;



	write_lock(&detail->hash_lock);

	spin_lock(&detail->hash_lock);

	rv = cache_is_valid(h);

	if (rv == -EAGAIN) {

		set_bit(CACHE_NEGATIVE, &h->flags);
@@ -247,7 +247,7 @@ static int try_to_negate_entry(struct cache_detail *detail, struct cache_head *h 
				   detail);

		rv = -ENOENT;

	}

	write_unlock(&detail->hash_lock);

	spin_unlock(&detail->hash_lock);

	cache_fresh_unlocked(h, detail);

	return rv;

}
@@ -357,7 +357,7 @@ static struct delayed_work cache_cleaner; 


void sunrpc_init_cache_detail(struct cache_detail *cd)

{

	rwlock_init(&cd->hash_lock);

	spin_lock_init(&cd->hash_lock);

	INIT_LIST_HEAD(&cd->queue);

	spin_lock(&cache_list_lock);

	cd->nextcheck = 0;
@@ -377,11 +377,11 @@ void sunrpc_destroy_cache_detail(struct cache_detail *cd) 
{

	cache_purge(cd);

	spin_lock(&cache_list_lock);

	write_lock(&cd->hash_lock);

	spin_lock(&cd->hash_lock);

	if (current_detail == cd)

		current_detail = NULL;

	list_del_init(&cd->others);

	write_unlock(&cd->hash_lock);

	spin_unlock(&cd->hash_lock);

	spin_unlock(&cache_list_lock);

	if (list_empty(&cache_list)) {

		/* module must be being unloaded so its safe to kill the worker */
@@ -438,7 +438,7 @@ static int cache_clean(void) 
		struct hlist_head *head;

		struct hlist_node *tmp;



		write_lock(&current_detail->hash_lock);

		spin_lock(&current_detail->hash_lock);



		/* Ok, now to clean this strand */
@@ -455,7 +455,7 @@ static int cache_clean(void) 
			break;

		}



		write_unlock(&current_detail->hash_lock);

		spin_unlock(&current_detail->hash_lock);

		d = current_detail;

		if (!ch)

			current_index ++;
@@ -510,9 +510,9 @@ void cache_purge(struct cache_detail *detail) 
	struct hlist_node *tmp = NULL;

	int i = 0;



	write_lock(&detail->hash_lock);

	spin_lock(&detail->hash_lock);

	if (!detail->entries) {

		write_unlock(&detail->hash_lock);

		spin_unlock(&detail->hash_lock);

		return;

	}
@@ -524,13 +524,13 @@ void cache_purge(struct cache_detail *detail) 
			detail->entries--;



			set_bit(CACHE_CLEANED, &ch->flags);

			write_unlock(&detail->hash_lock);

			spin_unlock(&detail->hash_lock);

			cache_fresh_unlocked(ch, detail);

			cache_put(ch, detail);

			write_lock(&detail->hash_lock);

			spin_lock(&detail->hash_lock);

		}

	}

	write_unlock(&detail->hash_lock);

	spin_unlock(&detail->hash_lock);

}

EXPORT_SYMBOL_GPL(cache_purge);
@@ -1873,13 +1873,13 @@ EXPORT_SYMBOL_GPL(sunrpc_cache_unregister_pipefs); 


void sunrpc_cache_unhash(struct cache_detail *cd, struct cache_head *h)

{

	write_lock(&cd->hash_lock);

	spin_lock(&cd->hash_lock);

	if (!hlist_unhashed(&h->cache_list)){

		hlist_del_init_rcu(&h->cache_list);

		cd->entries--;

		write_unlock(&cd->hash_lock);

		spin_unlock(&cd->hash_lock);

		cache_put(h, cd);

	} else

		write_unlock(&cd->hash_lock);

		spin_unlock(&cd->hash_lock);

}

EXPORT_SYMBOL_GPL(sunrpc_cache_unhash);