IB/core: Only update PKEY and GID caches on respective events

Both the PKEY and GID tables in an HCA can hold in the order of hundreds
entries. Reading them is expensive. Partly because the API for retrieving
them only returns a single entry at a time. Further, on certain
implementations, e.g., CX-3, the VFs are paravirtualized in this respect
and have to rely on the PF driver to perform the read. This again demands
VF to PF communication.

IB Core's cache is refreshed on all events. Hence, filter the refresh of
the PKEY and GID caches based on the event received being
IB_EVENT_PKEY_CHANGE and IB_EVENT_GID_CHANGE respectively.

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Link: https://lore.kernel.org/r/1621964949-28484-1-git-send-email-haakon.bugge@oracle.comSigned-off-by: NHåkon Bugge <haakon.bugge@oracle.com>
Reviewed-by: NLeon Romanovsky <leonro@nvidia.com>
Signed-off-by: NJason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/core/cache.c

@@ -1465,10 +1465,12 @@ static int config_non_roce_gid_cache(struct ib_device *device,
 }
 
 static int
-ib_cache_update(struct ib_device *device, u32 port, bool enforce_security)
+ib_cache_update(struct ib_device *device, u32 port, bool update_gids,
+		bool update_pkeys, bool enforce_security)
 {
 	struct ib_port_attr       *tprops = NULL;
-	struct ib_pkey_cache      *pkey_cache = NULL, *old_pkey_cache;
+	struct ib_pkey_cache      *pkey_cache = NULL;
+	struct ib_pkey_cache      *old_pkey_cache = NULL;
 	int                        i;
 	int                        ret;
 
@@ -1485,14 +1487,16 @@ ib_cache_update(struct ib_device *device, u32 port, bool enforce_security)
 		goto err;
 	}
 
-	if (!rdma_protocol_roce(device, port)) {
+	if (!rdma_protocol_roce(device, port) && update_gids) {
 		ret = config_non_roce_gid_cache(device, port,
 						tprops->gid_tbl_len);
 		if (ret)
 			goto err;
 	}
 
-	if (tprops->pkey_tbl_len) {
+	update_pkeys &= !!tprops->pkey_tbl_len;
+
+	if (update_pkeys) {
 		pkey_cache = kmalloc(struct_size(pkey_cache, table,
 						 tprops->pkey_tbl_len),
 				     GFP_KERNEL);
@@ -1517,9 +1521,10 @@ ib_cache_update(struct ib_device *device, u32 port, bool enforce_security)
 
 	write_lock_irq(&device->cache_lock);
 
-	old_pkey_cache = device->port_data[port].cache.pkey;
-
-	device->port_data[port].cache.pkey = pkey_cache;
+	if (update_pkeys) {
+		old_pkey_cache = device->port_data[port].cache.pkey;
+		device->port_data[port].cache.pkey = pkey_cache;
+	}
 	device->port_data[port].cache.lmc = tprops->lmc;
 	device->port_data[port].cache.port_state = tprops->state;
 
@@ -1551,6 +1556,8 @@ static void ib_cache_event_task(struct work_struct *_work)
 	 * the cache.
 	 */
 	ret = ib_cache_update(work->event.device, work->event.element.port_num,
+			      work->event.event == IB_EVENT_GID_CHANGE,
+			      work->event.event == IB_EVENT_PKEY_CHANGE,
 			      work->enforce_security);
 
 	/* GID event is notified already for individual GID entries by
@@ -1624,7 +1631,7 @@ int ib_cache_setup_one(struct ib_device *device)
 		return err;
 
 	rdma_for_each_port (device, p) {
-		err = ib_cache_update(device, p, true);
+		err = ib_cache_update(device, p, true, true, true);
 		if (err)
 			return err;
 	}