Commit d48cf356 authored by Trond Myklebust's avatar Trond Myklebust Committed by J. Bruce Fields
Browse files

SUNRPC: Remove non-RCU protected lookup 



Clean up the cache code by removing the non-RCU protected lookup.

Signed-off-by: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
parent a6482733

Documentation/filesystems/nfs/rpc-cache.txt

+3 −3
Original line number Diff line number Diff line
@@ -84,7 +84,7 @@ Creating a Cache 
		A message from user space has arrived to fill out a

		cache entry.  It is in 'buf' of length 'len'.

		cache_parse should parse this, find the item in the

		cache with sunrpc_cache_lookup, and update the item

		cache with sunrpc_cache_lookup_rcu, and update the item

		with sunrpc_cache_update.
@@ -95,7 +95,7 @@ Creating a Cache 
Using a cache

-------------



To find a value in a cache, call sunrpc_cache_lookup passing a pointer

To find a value in a cache, call sunrpc_cache_lookup_rcu passing a pointer

to the cache_head in a sample item with the 'key' fields filled in.

This will be passed to ->match to identify the target entry.  If no

entry is found, a new entry will be create, added to the cache, and
@@ -116,7 +116,7 @@ item does become valid, the deferred copy of the request will be 
revisited (->revisit).  It is expected that this method will

reschedule the request for processing.



The value returned by sunrpc_cache_lookup can also be passed to

The value returned by sunrpc_cache_lookup_rcu can also be passed to

sunrpc_cache_update to set the content for the item.  A second item is

passed which should hold the content.  If the item found by _lookup

has valid data, then it is discarded and a new item is created.  This

include/linux/sunrpc/cache.h

+0 −6
Original line number Diff line number Diff line
@@ -171,9 +171,6 @@ extern struct cache_head * 
sunrpc_cache_lookup_rcu(struct cache_detail *detail,

			struct cache_head *key, int hash);

extern struct cache_head *

sunrpc_cache_lookup(struct cache_detail *detail,

		    struct cache_head *key, int hash);

extern struct cache_head *

sunrpc_cache_update(struct cache_detail *detail,

		    struct cache_head *new, struct cache_head *old, int hash);
@@ -233,9 +230,6 @@ extern void sunrpc_cache_unregister_pipefs(struct cache_detail *); 
extern void sunrpc_cache_unhash(struct cache_detail *, struct cache_head *);



/* Must store cache_detail in seq_file->private if using next three functions */

extern void *cache_seq_start(struct seq_file *file, loff_t *pos);

extern void *cache_seq_next(struct seq_file *file, void *p, loff_t *pos);

extern void cache_seq_stop(struct seq_file *file, void *p);

extern void *cache_seq_start_rcu(struct seq_file *file, loff_t *pos);

extern void *cache_seq_next_rcu(struct seq_file *file, void *p, loff_t *pos);

extern void cache_seq_stop_rcu(struct seq_file *file, void *p);

net/sunrpc/cache.c

+4 −57
Original line number Diff line number Diff line
@@ -75,27 +75,6 @@ static struct cache_head *sunrpc_cache_find_rcu(struct cache_detail *detail, 
	return NULL;

}



static struct cache_head *sunrpc_cache_find(struct cache_detail *detail,

					    struct cache_head *key, int hash)

{

	struct hlist_head *head = &detail->hash_table[hash];

	struct cache_head *tmp;



	read_lock(&detail->hash_lock);

	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. */

				break;

			cache_get(tmp);

			read_unlock(&detail->hash_lock);

			return tmp;

		}

	}

	read_unlock(&detail->hash_lock);

	return NULL;

}



static struct cache_head *sunrpc_cache_add_entry(struct cache_detail *detail,

						 struct cache_head *key,

						 int hash)
@@ -154,20 +133,6 @@ struct cache_head *sunrpc_cache_lookup_rcu(struct cache_detail *detail, 
}

EXPORT_SYMBOL_GPL(sunrpc_cache_lookup_rcu);



struct cache_head *sunrpc_cache_lookup(struct cache_detail *detail,

				       struct cache_head *key, int hash)

{

	struct cache_head *ret;



	ret = sunrpc_cache_find(detail, key, hash);

	if (ret)

		return ret;

	/* Didn't find anything, insert an empty entry */

	return sunrpc_cache_add_entry(detail, key, hash);

}

EXPORT_SYMBOL_GPL(sunrpc_cache_lookup);





static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch);



static void cache_fresh_locked(struct cache_head *head, time_t expiry,
@@ -1369,17 +1334,7 @@ static void *__cache_seq_start(struct seq_file *m, loff_t *pos) 
				struct cache_head, cache_list);

}



void *cache_seq_start(struct seq_file *m, loff_t *pos)

	__acquires(cd->hash_lock)

{

	struct cache_detail *cd = m->private;



	read_lock(&cd->hash_lock);

	return __cache_seq_start(m, pos);

}

EXPORT_SYMBOL_GPL(cache_seq_start);



void *cache_seq_next(struct seq_file *m, void *p, loff_t *pos)

static void *cache_seq_next(struct seq_file *m, void *p, loff_t *pos)

{

	struct cache_head *ch = p;

	int hash = (*pos >> 32);
@@ -1411,14 +1366,6 @@ void *cache_seq_next(struct seq_file *m, void *p, loff_t *pos) 
}

EXPORT_SYMBOL_GPL(cache_seq_next);



void cache_seq_stop(struct seq_file *m, void *p)

	__releases(cd->hash_lock)

{

	struct cache_detail *cd = m->private;

	read_unlock(&cd->hash_lock);

}

EXPORT_SYMBOL_GPL(cache_seq_stop);



void *cache_seq_start_rcu(struct seq_file *m, loff_t *pos)

	__acquires(RCU)

{
@@ -1466,9 +1413,9 @@ static int c_show(struct seq_file *m, void *p) 
}



static const struct seq_operations cache_content_op = {

	.start	= cache_seq_start,

	.next	= cache_seq_next,

	.stop	= cache_seq_stop,

	.start	= cache_seq_start_rcu,

	.next	= cache_seq_next_rcu,

	.stop	= cache_seq_stop_rcu,

	.show	= c_show,

};