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Commit 471a930a authored by Kinglong Mee's avatar Kinglong Mee Committed by J. Bruce Fields
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SUNRPC: Drop all entries from cache_detail when cache_purge() 



User always free the cache_detail after sunrpc_destroy_cache_detail(),
so, it must cleanup up entries that left in the cache_detail,
otherwise, NULL reference may be caused when using the left entries.

Also, NeriBrown suggests "write a stand-alone cache_purge()."

v3, move the cache_fresh_unlocked() out of write lock,
v2, a stand-alone cache_purge(), not only for sunrpc_destroy_cache_detail

Signed-off-by: default avatarKinglong Mee <kinglongmee@gmail.com>
Reviewed-by: default avatarNeilBrown <neilb@suse.com>
Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
parent 81fa3275

net/sunrpc/cache.c

+26 −15
Original line number Diff line number Diff line
@@ -362,11 +362,6 @@ void sunrpc_destroy_cache_detail(struct cache_detail *cd) 
	cache_purge(cd);

	spin_lock(&cache_list_lock);

	write_lock(&cd->hash_lock);

	if (cd->entries) {

		write_unlock(&cd->hash_lock);

		spin_unlock(&cache_list_lock);

		goto out;

	}

	if (current_detail == cd)

		current_detail = NULL;

	list_del_init(&cd->others);
@@ -376,9 +371,6 @@ void sunrpc_destroy_cache_detail(struct cache_detail *cd) 
		/* module must be being unloaded so its safe to kill the worker */

		cancel_delayed_work_sync(&cache_cleaner);

	}

	return;

out:

	printk(KERN_ERR "RPC: failed to unregister %s cache\n", cd->name);

}

EXPORT_SYMBOL_GPL(sunrpc_destroy_cache_detail);
@@ -497,13 +489,32 @@ EXPORT_SYMBOL_GPL(cache_flush); 


void cache_purge(struct cache_detail *detail)

{

	time_t now = seconds_since_boot();

	if (detail->flush_time >= now)

		now = detail->flush_time + 1;

	/* 'now' is the maximum value any 'last_refresh' can have */

	detail->flush_time = now;

	detail->nextcheck = seconds_since_boot();

	cache_flush();

	struct cache_head *ch = NULL;

	struct hlist_head *head = NULL;

	struct hlist_node *tmp = NULL;

	int i = 0;



	write_lock(&detail->hash_lock);

	if (!detail->entries) {

		write_unlock(&detail->hash_lock);

		return;

	}



	dprintk("RPC: %d entries in %s cache\n", detail->entries, detail->name);

	for (i = 0; i < detail->hash_size; i++) {

		head = &detail->hash_table[i];

		hlist_for_each_entry_safe(ch, tmp, head, cache_list) {

			hlist_del_init(&ch->cache_list);

			detail->entries--;



			set_bit(CACHE_CLEANED, &ch->flags);

			write_unlock(&detail->hash_lock);

			cache_fresh_unlocked(ch, detail);

			cache_put(ch, detail);

			write_lock(&detail->hash_lock);

		}

	}

	write_unlock(&detail->hash_lock);

}

EXPORT_SYMBOL_GPL(cache_purge);