nfsd: Clean up drc cache in preparation for global spinlock elimination

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

diff --git a/fs/nfsd/nfscache.c b/fs/nfsd/nfscache.c
index ff9567633245995579be4403f7189de5a7ab2321..c74bcd628c4f43ad64d254b171658214aa1d0833 100644 (file)
--- a/fs/nfsd/nfscache.c
+++ b/fs/nfsd/nfscache.c
@@ -27,7 +27,11 @@
  */
 #define TARGET_BUCKET_SIZE     64
 
-static struct hlist_head *     cache_hash;
+struct nfsd_drc_bucket {
+       struct hlist_head cache_hash;
+};
+
+static struct nfsd_drc_bucket  *drc_hashtbl;
 static struct list_head        lru_head;
 static struct kmem_cache       *drc_slab;
 
@@ -116,6 +120,12 @@ nfsd_hashsize(unsigned int limit)
        return roundup_pow_of_two(limit / TARGET_BUCKET_SIZE);
 }
 
+static u32
+nfsd_cache_hash(__be32 xid)
+{
+       return hash_32(be32_to_cpu(xid), maskbits);
+}
+
 static struct svc_cacherep *
 nfsd_reply_cache_alloc(void)
 {
@@ -170,8 +180,8 @@ int nfsd_reply_cache_init(void)
        if (!drc_slab)
                goto out_nomem;
 
-       cache_hash = kcalloc(hashsize, sizeof(struct hlist_head), GFP_KERNEL);
-       if (!cache_hash)
+       drc_hashtbl = kcalloc(hashsize, sizeof(*drc_hashtbl), GFP_KERNEL);
+       if (!drc_hashtbl)
                goto out_nomem;
 
        return 0;
@@ -193,8 +203,8 @@ void nfsd_reply_cache_shutdown(void)
                nfsd_reply_cache_free_locked(rp);
        }
 
-       kfree (cache_hash);
-       cache_hash = NULL;
+       kfree (drc_hashtbl);
+       drc_hashtbl = NULL;
 
        if (drc_slab) {
                kmem_cache_destroy(drc_slab);
@@ -218,15 +228,10 @@ lru_put_end(struct svc_cacherep *rp)
  * Move a cache entry from one hash list to another
  */
 static void
-hash_refile(struct svc_cacherep *rp)
+hash_refile(struct nfsd_drc_bucket *b, struct svc_cacherep *rp)
 {
        hlist_del_init(&rp->c_hash);
-       /*
-        * No point in byte swapping c_xid since we're just using it to pick
-        * a hash bucket.
-        */
-       hlist_add_head(&rp->c_hash, cache_hash +
-                       hash_32((__force u32)rp->c_xid, maskbits));
+       hlist_add_head(&rp->c_hash, &b->cache_hash);
 }
 
 /*
@@ -355,17 +360,13 @@ nfsd_cache_match(struct svc_rqst *rqstp, __wsum csum, struct svc_cacherep *rp)
  * NULL on failure.
  */
 static struct svc_cacherep *
-nfsd_cache_search(struct svc_rqst *rqstp, __wsum csum)
+nfsd_cache_search(struct nfsd_drc_bucket *b, struct svc_rqst *rqstp,
+               __wsum csum)
 {
        struct svc_cacherep     *rp, *ret = NULL;
-       struct hlist_head       *rh;
+       struct hlist_head       *rh = &b->cache_hash;
        unsigned int            entries = 0;
 
-       /*
-        * No point in byte swapping rq_xid since we're just using it to pick
-        * a hash bucket.
-        */
-       rh = &cache_hash[hash_32((__force u32)rqstp->rq_xid, maskbits)];
        hlist_for_each_entry(rp, rh, c_hash) {
                ++entries;
                if (nfsd_cache_match(rqstp, csum, rp)) {
@@ -403,6 +404,8 @@ nfsd_cache_lookup(struct svc_rqst *rqstp)
                                vers = rqstp->rq_vers,
                                proc = rqstp->rq_proc;
        __wsum                  csum;
+       u32 hash = nfsd_cache_hash(xid);
+       struct nfsd_drc_bucket *b = &drc_hashtbl[hash];
        unsigned long           age;
        int type = rqstp->rq_cachetype;
        int rtn = RC_DOIT;
@@ -429,7 +432,7 @@ nfsd_cache_lookup(struct svc_rqst *rqstp)
        /* go ahead and prune the cache */
        prune_cache_entries();
 
-       found = nfsd_cache_search(rqstp, csum);
+       found = nfsd_cache_search(b, rqstp, csum);
        if (found) {
                if (likely(rp))
                        nfsd_reply_cache_free_locked(rp);
@@ -454,7 +457,7 @@ nfsd_cache_lookup(struct svc_rqst *rqstp)
        rp->c_len = rqstp->rq_arg.len;
        rp->c_csum = csum;
 
-       hash_refile(rp);
+       hash_refile(b, rp);
        lru_put_end(rp);
 
        /* release any buffer */