NFS: Get rid of the nfs_rdata_mempool

We don't need a mempool in order to guarantee reliable NFS read performance.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/read.c

@@ -35,16 +35,13 @@ static const struct rpc_call_ops nfs_read_partial_ops;
 static const struct rpc_call_ops nfs_read_full_ops;
 
 static struct kmem_cache *nfs_rdata_cachep;
-static mempool_t *nfs_rdata_mempool;
-
-#define MIN_POOL_READ	(32)
 
 struct nfs_read_data *nfs_readdata_alloc(unsigned int pagecount)
 {
-	struct nfs_read_data *p = mempool_alloc(nfs_rdata_mempool, GFP_KERNEL);
+	struct nfs_read_data *p;
 
+	p = kmem_cache_zalloc(nfs_rdata_cachep, GFP_KERNEL);
 	if (p) {
-		memset(p, 0, sizeof(*p));
 		INIT_LIST_HEAD(&p->pages);
 		p->npages = pagecount;
 		if (pagecount <= ARRAY_SIZE(p->page_array))
@@ -52,7 +49,7 @@ struct nfs_read_data *nfs_readdata_alloc(unsigned int pagecount)
 		else {
 			p->pagevec = kcalloc(pagecount, sizeof(struct page *), GFP_KERNEL);
 			if (!p->pagevec) {
-				mempool_free(p, nfs_rdata_mempool);
+				kmem_cache_free(nfs_rdata_cachep, p);
 				p = NULL;
 			}
 		}
@@ -64,7 +61,7 @@ void nfs_readdata_free(struct nfs_read_data *p)
 {
 	if (p && (p->pagevec != &p->page_array[0]))
 		kfree(p->pagevec);
-	mempool_free(p, nfs_rdata_mempool);
+	kmem_cache_free(nfs_rdata_cachep, p);
 }
 
 void nfs_readdata_release(struct nfs_read_data *rdata)
@@ -716,16 +713,10 @@ int __init nfs_init_readpagecache(void)
 	if (nfs_rdata_cachep == NULL)
 		return -ENOMEM;
 
-	nfs_rdata_mempool = mempool_create_slab_pool(MIN_POOL_READ,
-						     nfs_rdata_cachep);
-	if (nfs_rdata_mempool == NULL)
-		return -ENOMEM;
-
 	return 0;
 }
 
 void nfs_destroy_readpagecache(void)
 {
-	mempool_destroy(nfs_rdata_mempool);
 	kmem_cache_destroy(nfs_rdata_cachep);
 }