[RFC rdma-core] srp_daemon: handle SM lid change

Nicolas Morey-Chaisemartin
2017-12-08T09:36:22Z

When srp_daemon was running and the master SM host changes,
srp_daemon output these errors at every scan:
srp_daemon[25394]: No response to inform info registration
srp_daemon[25394]: Fail to register to traps, maybe there is no opensm
running on fabric or IB port is down

This was introduced by commit 4952e5f Fix a memory leak.
A side effect of this patch was that create_ah was only called when the
port lid changes. Which meant register_to_traps used an older, obsolete,
version of sm_lid and failed to connect to it.

This patch fixes this behaviour by checking for both local lid changes and
SM lid changes, and calling create_ah on any of these events.

Signed-off-by: Nicolas Morey-Chaisemartin <NMoreyChaisemartin-IBi9RG/b67k@public.gmane.org>
---

This fixes the bug for me but I'm waiting for feedback from the customer to make sure it fixes the issue for him too.
And not just part of it.
I'll repost a proper patch (non RFC) once he confirms it.

srp_daemon/srp_daemon.c | 10 ++++++----
srp_daemon/srp_daemon.h | 2 +-
srp_daemon/srp_handle_traps.c | 16 ++++++++++++----
3 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/srp_daemon/srp_daemon.c b/srp_daemon/srp_daemon.c
index 2465ccd9..36df5c3b 100644
--- a/srp_daemon/srp_daemon.c
+++ b/srp_daemon/srp_daemon.c
@@ -1103,7 +1103,7 @@ static int get_shared_pkeys(struct resources *res,
int i, num_pkeys = 0;
uint16_t pkey;
uint16_t local_port_lid = get_port_lid(res->ud_res->ib_ctx,
- config->port_num);
+ config->port_num, NULL);

in_mad_buf = malloc(sizeof(struct ib_user_mad) +
node_table_response_size);
@@ -2092,7 +2092,7 @@ int main(int argc, char *argv[])
{
int ret;
struct resources *res;
- uint16_t lid;
+ uint16_t lid, sm_lid;
uint16_t pkey;
union umad_gid gid;
struct target_details *target;
@@ -2196,8 +2196,10 @@ catas_start:

pr_debug("Starting a recalculation\n");
port_lid = get_port_lid(res->ud_res->ib_ctx,
- config->port_num);
- if (port_lid != res->ud_res->port_attr.lid) {
+ config->port_num, &sm_lid);
+ if (port_lid != res->ud_res->port_attr.lid ||
+ sm_lid != res->ud_res->port_attr.sm_lid) {
+
if (res->ud_res->ah) {
ibv_destroy_ah(res->ud_res->ah);
res->ud_res->ah = NULL;
diff --git a/srp_daemon/srp_daemon.h b/srp_daemon/srp_daemon.h
index 5d268ed3..864b3d42 100644
--- a/srp_daemon/srp_daemon.h
+++ b/srp_daemon/srp_daemon.h
@@ -299,7 +299,7 @@ void *run_thread_listen_to_events(void *res_in);
int get_node(struct umad_resources *umad_res, uint16_t dlid, uint64_t *guid);
int create_trap_resources(struct ud_resources *ud_res);
int register_to_traps(struct resources *res, int subscribe);
-uint16_t get_port_lid(struct ibv_context *ib_ctx, int port_num);
+uint16_t get_port_lid(struct ibv_context *ib_ctx, int port_num, uint16_t *sm_lid);
int create_ah(struct ud_resources *ud_res);
void push_gid_to_list(struct sync_resources *res, union umad_gid *gid,
uint16_t pkey);
diff --git a/srp_daemon/srp_handle_traps.c b/srp_daemon/srp_handle_traps.c
index 6d94634e..e546d491 100644
--- a/srp_daemon/srp_handle_traps.c
+++ b/srp_daemon/srp_handle_traps.c
@@ -340,12 +340,20 @@ int ud_resources_create(struct ud_resources *res)
return 0;
}

-uint16_t get_port_lid(struct ibv_context *ib_ctx, int port_num)
+uint16_t get_port_lid(struct ibv_context *ib_ctx, int port_num, uint16_t *sm_lid)
{
struct ibv_port_attr port_attr;
+ int ret;
+
+ ret = ibv_query_port(ib_ctx, port_num, &port_attr);

- return ibv_query_port(ib_ctx, port_num, &port_attr) == 0 ?
- port_attr.lid : 0;
+ if (!ret) {
+ if (sm_lid)
+ *sm_lid = port_attr.sm_lid;
+ return port_attr.lid;
+ }
+
+ return 0;
}

int create_ah(struct ud_resources *ud_res)
@@ -641,7 +649,7 @@ static int register_to_trap(struct sync_resources *sync_res,
pthread_mutex_unlock(res->mad_buffer_mutex);
} while (rc == 2); // while old response.

- } while (rc == 0 && ++counter < 3);
+ } while (rc == 0 && ++counter < 5);

if (counter==3) {
pr_err("No response to inform info registration\n");
--
2.15.1.272.g8e603414b