LU-10391 socklnd: factor out key calculation for ksnd_peers

The hash_table library requires a "long" to be used as a key.  We
currently provide the nid, which at 64bits is a suitable long on 64bit
hosts, but isn't really correct on 32bit hosts.

When we change to an extend nid (which is 160bits) it will be even
less appropriate.

So create a separate function to compute a 'long' key, and implement
by simply xoring 'long'-sized parts of the nid together.  On a 64bit
machine, this is currently optimized away for lnet_nid_t, but that
will change when we convert to struct lnet_nid.

This new function is placed in lnet-types.h as it will be more
generally useful later.

The hash_table library calls hash_long() on the key, so we don't need
to do anything more interesting than xoring.

Test-Parameters: trivial
Test-Parameters: serverversion=2.12 serverdistro=el7.9 testlist=runtests
Test-Parameters: clientversion=2.12 testlist=runtests
Signed-off-by: Mr NeilBrown <neilb@suse.de>
Change-Id: I22c59a87c9872bb59a2f47c2a8c57b287ed53ed3
Reviewed-on: https://review.whamcloud.com/42103
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Chris Horn <chris.horn@hpe.com>
Reviewed-by: Serguei Smirnov <ssmirnov@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>

diff --git a/lnet/include/uapi/linux/lnet/lnet-types.h b/lnet/include/uapi/linux/lnet/lnet-types.h
index f00d84f..da5b03c 100644 (file)
--- a/lnet/include/uapi/linux/lnet/lnet-types.h
+++ b/lnet/include/uapi/linux/lnet/lnet-types.h
@@ -158,6 +158,16 @@ static inline int nid_same(const struct lnet_nid *n1,
                n1->nid_addr[3] == n2->nid_addr[3];
 }
 
+/* This can be used when we need to hash a nid */
+static inline unsigned long nidhash(lnet_nid_t nid)
+{
+       unsigned long hash = 0;
+
+       hash ^= LNET_NIDNET(nid);
+       hash ^= LNET_NIDADDR(nid);
+       return hash;
+}
+
 struct lnet_counters_health {
        __u32   lch_rst_alloc;
        __u32   lch_resend_count;

diff --git a/lnet/klnds/socklnd/socklnd.c b/lnet/klnds/socklnd/socklnd.c
index 307e16c..ad93203 100644 (file)
--- a/lnet/klnds/socklnd/socklnd.c
+++ b/lnet/klnds/socklnd/socklnd.c
@@ -221,9 +221,10 @@ struct ksock_peer_ni *
 ksocknal_find_peer_locked(struct lnet_ni *ni, struct lnet_process_id id)
 {
        struct ksock_peer_ni *peer_ni;
+       unsigned long hash = nidhash(id.nid);
 
        hash_for_each_possible(ksocknal_data.ksnd_peers, peer_ni,
-                              ksnp_list, id.nid) {
+                              ksnp_list, hash) {
                LASSERT(!peer_ni->ksnp_closing);
 
                if (peer_ni->ksnp_ni != ni)
@@ -598,7 +599,8 @@ ksocknal_add_peer(struct lnet_ni *ni, struct lnet_process_id id,
                peer_ni = peer2;
        } else {
                /* peer_ni table takes my ref on peer_ni */
-               hash_add(ksocknal_data.ksnd_peers, &peer_ni->ksnp_list, id.nid);
+               hash_add(ksocknal_data.ksnd_peers, &peer_ni->ksnp_list,
+                        nidhash(id.nid));
        }
 
        ksocknal_add_conn_cb_locked(peer_ni, conn_cb);
@@ -652,7 +654,8 @@ ksocknal_del_peer(struct lnet_ni *ni, struct lnet_process_id id, __u32 ip)
        write_lock_bh(&ksocknal_data.ksnd_global_lock);
 
        if (id.nid != LNET_NID_ANY) {
-               lo = hash_min(id.nid, HASH_BITS(ksocknal_data.ksnd_peers));
+               lo = hash_min(nidhash(id.nid),
+                             HASH_BITS(ksocknal_data.ksnd_peers));
                hi = lo;
        } else {
                lo = 0;
@@ -924,7 +927,7 @@ ksocknal_create_conn(struct lnet_ni *ni, struct ksock_conn_cb *conn_cb,
                        /* NB this puts an "empty" peer_ni in the peer_ni
                         * table (which takes my ref) */
                        hash_add(ksocknal_data.ksnd_peers,
-                                &peer_ni->ksnp_list, peerid.nid);
+                                &peer_ni->ksnp_list, nidhash(peerid.nid));
                } else {
                        ksocknal_peer_decref(peer_ni);
                        peer_ni = peer2;
@@ -1544,7 +1547,8 @@ ksocknal_close_matching_conns(struct lnet_process_id id, __u32 ipaddr)
        write_lock_bh(&ksocknal_data.ksnd_global_lock);
 
        if (id.nid != LNET_NID_ANY) {
-               lo = hash_min(id.nid, HASH_BITS(ksocknal_data.ksnd_peers));
+               lo = hash_min(nidhash(id.nid),
+                             HASH_BITS(ksocknal_data.ksnd_peers));
                hi = lo;
        } else {
                lo = 0;
@@ -1638,7 +1642,8 @@ ksocknal_push(struct lnet_ni *ni, struct lnet_process_id id)
        int rc = -ENOENT;
 
        if (id.nid != LNET_NID_ANY) {
-               lo = hash_min(id.nid, HASH_BITS(ksocknal_data.ksnd_peers));
+               lo = hash_min(nidhash(id.nid),
+                             HASH_BITS(ksocknal_data.ksnd_peers));
                hi = lo;
        } else {
                lo = 0;