net/smc: fix work request handling

Wait for pending sends only when smc_switch_conns() found a link to move
the connections to. Do not wait during link freeing, this can lead to
permanent hang situations. And refuse to provide a new tx slot on an
unusable link.

Fixes: c6f02ebeea3a ("net/smc: switch connections to alternate link")
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>

diff --git a/net/smc/smc_llc.c b/net/smc/smc_llc.c
index df164232574bf885e018052aff7cddcfe82873a0..c1a038689c63cbe9c985b2a6c635c28131e128fe 100644 (file)
--- a/net/smc/smc_llc.c
+++ b/net/smc/smc_llc.c
@@ -1241,8 +1241,8 @@ static void smc_llc_process_cli_delete_link(struct smc_link_group *lgr)
        smc_llc_send_message(lnk, &qentry->msg); /* response */
 
        if (smc_link_downing(&lnk_del->state)) {
-               smc_switch_conns(lgr, lnk_del, false);
-               smc_wr_tx_wait_no_pending_sends(lnk_del);
+               if (smc_switch_conns(lgr, lnk_del, false))
+                       smc_wr_tx_wait_no_pending_sends(lnk_del);
        }
        smcr_link_clear(lnk_del, true);
 
@@ -1316,8 +1316,8 @@ static void smc_llc_process_srv_delete_link(struct smc_link_group *lgr)
                goto out; /* asymmetric link already deleted */
 
        if (smc_link_downing(&lnk_del->state)) {
-               smc_switch_conns(lgr, lnk_del, false);
-               smc_wr_tx_wait_no_pending_sends(lnk_del);
+               if (smc_switch_conns(lgr, lnk_del, false))
+                       smc_wr_tx_wait_no_pending_sends(lnk_del);
        }
        if (!list_empty(&lgr->list)) {
                /* qentry is either a request from peer (send it back to

diff --git a/net/smc/smc_wr.c b/net/smc/smc_wr.c
index 7239ba9b99dc6eb9b0f437064ce1a64c88139d86..1e23cdd41eb1ec7740624e1269abe630c964380c 100644 (file)
--- a/net/smc/smc_wr.c
+++ b/net/smc/smc_wr.c
@@ -169,6 +169,8 @@ void smc_wr_tx_cq_handler(struct ib_cq *ib_cq, void *cq_context)
 static inline int smc_wr_tx_get_free_slot_index(struct smc_link *link, u32 *idx)
 {
        *idx = link->wr_tx_cnt;
+       if (!smc_link_usable(link))
+               return -ENOLINK;
        for_each_clear_bit(*idx, link->wr_tx_mask, link->wr_tx_cnt) {
                if (!test_and_set_bit(*idx, link->wr_tx_mask))
                        return 0;
@@ -560,15 +562,15 @@ void smc_wr_free_link(struct smc_link *lnk)
 {
        struct ib_device *ibdev;
 
+       if (!lnk->smcibdev)
+               return;
+       ibdev = lnk->smcibdev->ibdev;
+
        if (smc_wr_tx_wait_no_pending_sends(lnk))
                memset(lnk->wr_tx_mask, 0,
                       BITS_TO_LONGS(SMC_WR_BUF_CNT) *
                                                sizeof(*lnk->wr_tx_mask));
 
-       if (!lnk->smcibdev)
-               return;
-       ibdev = lnk->smcibdev->ibdev;
-
        if (lnk->wr_rx_dma_addr) {
                ib_dma_unmap_single(ibdev, lnk->wr_rx_dma_addr,
                                    SMC_WR_BUF_SIZE * lnk->wr_rx_cnt,