net/smc: unlock LGR pending lock earlier for SMC-D (62c7139f) · Commits · 戴 / test

If SMC client and server connections are both established at the same time, smc_connect_ism() cannot send a CLC confirm message while smc_listen_work() is waiting for one due to lock contention. This can result in timeouts in smc_clc_wait_msg() and failed SMC connections. In case of SMC-D, the LGR pending lock is not needed while smc_listen_work() is waiting for the CLC confirm message. So, this patch releases the lock earlier for SMC-D to avoid the locking issue. Signed-off-by:

Hans Wippel <hwippel@linux.ibm.com> Signed-off-by:

Ursula Braun <ubraun@linux.ibm.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

net/smc/af_smc.c

+9 −5

Original line number	Diff line number	Diff line
		@@ -1287,10 +1287,15 @@ static void smc_listen_work(struct work_struct *work)
		return;
		}

		/* SMC-D does not need this lock any more */
		if (ism_supported)
		mutex_unlock(&smc_create_lgr_pending);

		/* receive SMC Confirm CLC message */
		reason_code = smc_clc_wait_msg(new_smc, &cclc, sizeof(cclc),
		SMC_CLC_CONFIRM, CLC_WAIT_TIME);
		if (reason_code) {
		if (!ism_supported)
		mutex_unlock(&smc_create_lgr_pending);
		smc_listen_decline(new_smc, reason_code, local_contact);
		return;
		@@ -1298,13 +1303,12 @@ static void smc_listen_work(struct work_struct *work)

		/* finish worker */
		if (!ism_supported) {
		if (smc_listen_rdma_finish(new_smc, &cclc, local_contact)) {
		rc = smc_listen_rdma_finish(new_smc, &cclc, local_contact);
		mutex_unlock(&smc_create_lgr_pending);
		if (rc)
		return;
		}
		}
		smc_conn_save_peer_info(new_smc, &cclc);
		mutex_unlock(&smc_create_lgr_pending);
		smc_listen_out_connected(new_smc);
		}

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