Commit fffe83c8 authored Sep 03, 2020 by Karsten Graul Committed by David S. Miller Sep 03, 2020

net/smc: fix toleration of fake add_link messages

Older SMCR implementations had no link failover support and used one
link only. Because the handshake protocol requires to try the
establishment of a second link the old code sent a fake add_link message
and declined any server response afterwards.
The current code supports multiple links and inspects the received fake
add_link message more closely. To tolerate the fake add_link messages
smc_llc_is_local_add_link() needs an improved check of the message to
be able to separate between locally enqueued and fake add_link messages.
And smc_llc_cli_add_link() needs to check if the provided qp_mtu size is
invalid and reject the add_link request in that case.

Fixes: c48254fa ("net/smc: move add link processing for new device into llc layer")
Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 55669934

net/smc/smc_llc.c

+14 −1

Original line number	Diff line number	Diff line
		@@ -841,6 +841,9 @@ int smc_llc_cli_add_link(struct smc_link link, struct smc_llc_qentry qentry)
		struct smc_init_info ini;
		int lnk_idx, rc = 0;

		if (!llc->qp_mtu)
		goto out_reject;

		ini.vlan_id = lgr->vlan_id;
		smc_pnet_find_alt_roce(lgr, &ini, link->smcibdev);
		if (!memcmp(llc->sender_gid, link->peer_gid, SMC_GID_SIZE) &&
		@@ -917,10 +920,20 @@ out:
		kfree(qentry);
		}

		static bool smc_llc_is_empty_llc_message(union smc_llc_msg *llc)
		{
		int i;

		for (i = 0; i < ARRAY_SIZE(llc->raw.data); i++)
		if (llc->raw.data[i])
		return false;
		return true;
		}

		static bool smc_llc_is_local_add_link(union smc_llc_msg *llc)
		{
		if (llc->raw.hdr.common.type == SMC_LLC_ADD_LINK &&
		!llc->add_link.qp_mtu && !llc->add_link.link_num)
		smc_llc_is_empty_llc_message(llc))
		return true;
		return false;
		}

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