net/smc: do not call dma sync for unmapped memory

The dma related ...sync_sg... functions check the link state before the
dma function is actually called. But the check in smc_link_usable()
allows links in ACTIVATING state which are not yet mapped to dma memory.
Under high load it may happen that the sync_sg functions are called for
such a link which results in an debug output like
   DMA-API: mlx5_core 0002:00:00.0: device driver tries to sync
   DMA memory it has not allocated [device address=0x0000000103370000]
   [size=65536 bytes]
To fix that introduce a helper to check for the link state ACTIVE and
use it where appropriate. And move the link state update to ACTIVATING
to the end of smcr_link_init() when most initial setup is done.

Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Fixes: d854fcbfaeda ("net/smc: add new link state and related helpers")
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index f80591567a3dbb99967527de69e390994fb6e54c..d091509b5982f234eae1345a0ae98573b467adc9 100644 (file)
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -352,7 +352,7 @@ static int smcr_lgr_reg_rmbs(struct smc_link *link,
         */
        mutex_lock(&lgr->llc_conf_mutex);
        for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
-               if (lgr->lnk[i].state != SMC_LNK_ACTIVE)
+               if (!smc_link_active(&lgr->lnk[i]))
                        continue;
                rc = smcr_link_reg_rmb(&lgr->lnk[i], rmb_desc);
                if (rc)

diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c
index 2e965de7412d694e8429e301bb435353f5ff3fa6..42ba227f3e97b956c2f1853e23cdce5b0ce01a6d 100644 (file)
--- a/net/smc/smc_core.c
+++ b/net/smc/smc_core.c
@@ -318,7 +318,6 @@ int smcr_link_init(struct smc_link_group *lgr, struct smc_link *lnk,
 
        get_device(&ini->ib_dev->ibdev->dev);
        atomic_inc(&ini->ib_dev->lnk_cnt);
-       lnk->state = SMC_LNK_ACTIVATING;
        lnk->link_id = smcr_next_link_id(lgr);
        lnk->lgr = lgr;
        lnk->link_idx = link_idx;
@@ -354,6 +353,7 @@ int smcr_link_init(struct smc_link_group *lgr, struct smc_link *lnk,
        rc = smc_wr_create_link(lnk);
        if (rc)
                goto destroy_qp;
+       lnk->state = SMC_LNK_ACTIVATING;
        return 0;
 
 destroy_qp:
@@ -542,8 +542,7 @@ struct smc_link *smc_switch_conns(struct smc_link_group *lgr,
        smc_wr_wakeup_tx_wait(from_lnk);
 
        for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
-               if (lgr->lnk[i].state != SMC_LNK_ACTIVE ||
-                   i == from_lnk->link_idx)
+               if (!smc_link_active(&lgr->lnk[i]) || i == from_lnk->link_idx)
                        continue;
                if (is_dev_err && from_lnk->smcibdev == lgr->lnk[i].smcibdev &&
                    from_lnk->ibport == lgr->lnk[i].ibport) {
@@ -1269,7 +1268,7 @@ static bool smcr_lgr_match(struct smc_link_group *lgr,
                return false;
 
        for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
-               if (lgr->lnk[i].state != SMC_LNK_ACTIVE)
+               if (!smc_link_active(&lgr->lnk[i]))
                        continue;
                if ((lgr->role == SMC_SERV || lgr->lnk[i].peer_qpn == clcqpn) &&
                    !memcmp(lgr->lnk[i].peer_gid, &lcl->gid, SMC_GID_SIZE) &&
@@ -1717,14 +1716,14 @@ static int __smc_buf_create(struct smc_sock *smc, bool is_smcd, bool is_rmb)
 
 void smc_sndbuf_sync_sg_for_cpu(struct smc_connection *conn)
 {
-       if (!conn->lgr || conn->lgr->is_smcd || !smc_link_usable(conn->lnk))
+       if (!conn->lgr || conn->lgr->is_smcd || !smc_link_active(conn->lnk))
                return;
        smc_ib_sync_sg_for_cpu(conn->lnk, conn->sndbuf_desc, DMA_TO_DEVICE);
 }
 
 void smc_sndbuf_sync_sg_for_device(struct smc_connection *conn)
 {
-       if (!conn->lgr || conn->lgr->is_smcd || !smc_link_usable(conn->lnk))
+       if (!conn->lgr || conn->lgr->is_smcd || !smc_link_active(conn->lnk))
                return;
        smc_ib_sync_sg_for_device(conn->lnk, conn->sndbuf_desc, DMA_TO_DEVICE);
 }
@@ -1736,7 +1735,7 @@ void smc_rmb_sync_sg_for_cpu(struct smc_connection *conn)
        if (!conn->lgr || conn->lgr->is_smcd)
                return;
        for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
-               if (!smc_link_usable(&conn->lgr->lnk[i]))
+               if (!smc_link_active(&conn->lgr->lnk[i]))
                        continue;
                smc_ib_sync_sg_for_cpu(&conn->lgr->lnk[i], conn->rmb_desc,
                                       DMA_FROM_DEVICE);
@@ -1750,7 +1749,7 @@ void smc_rmb_sync_sg_for_device(struct smc_connection *conn)
        if (!conn->lgr || conn->lgr->is_smcd)
                return;
        for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
-               if (!smc_link_usable(&conn->lgr->lnk[i]))
+               if (!smc_link_active(&conn->lgr->lnk[i]))
                        continue;
                smc_ib_sync_sg_for_device(&conn->lgr->lnk[i], conn->rmb_desc,
                                          DMA_FROM_DEVICE);

diff --git a/net/smc/smc_core.h b/net/smc/smc_core.h
index c3ff512fd8911ffedb3b9e2915566684515995a9..1c4d5439d0ff283208ab92c0249abfe72075e216 100644 (file)
--- a/net/smc/smc_core.h
+++ b/net/smc/smc_core.h
@@ -349,6 +349,11 @@ static inline bool smc_link_usable(struct smc_link *lnk)
        return true;
 }
 
+static inline bool smc_link_active(struct smc_link *lnk)
+{
+       return lnk->state == SMC_LNK_ACTIVE;
+}
+
 struct smc_sock;
 struct smc_clc_msg_accept_confirm;
 struct smc_clc_msg_local;

diff --git a/net/smc/smc_llc.c b/net/smc/smc_llc.c
index fa8cd57a9b32cd88676fc4ccf468a0e35219f552..df5b0a6ea8488ffb53fb5a4aa5b564d557ee4400 100644 (file)
--- a/net/smc/smc_llc.c
+++ b/net/smc/smc_llc.c
@@ -428,7 +428,7 @@ static int smc_llc_send_confirm_rkey(struct smc_link *send_link,
        rtok_ix = 1;
        for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
                link = &send_link->lgr->lnk[i];
-               if (link->state == SMC_LNK_ACTIVE && link != send_link) {
+               if (smc_link_active(link) && link != send_link) {
                        rkeyllc->rtoken[rtok_ix].link_id = link->link_id;
                        rkeyllc->rtoken[rtok_ix].rmb_key =
                                htonl(rmb_desc->mr_rx[link->link_idx]->rkey);
@@ -944,7 +944,7 @@ static int smc_llc_active_link_count(struct smc_link_group *lgr)
        int i, link_count = 0;
 
        for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
-               if (!smc_link_usable(&lgr->lnk[i]))
+               if (!smc_link_active(&lgr->lnk[i]))
                        continue;
                link_count++;
        }
@@ -1622,7 +1622,7 @@ static void smc_llc_rx_response(struct smc_link *link,
 
        switch (llc_type) {
        case SMC_LLC_TEST_LINK:
-               if (link->state == SMC_LNK_ACTIVE)
+               if (smc_link_active(link))
                        complete(&link->llc_testlink_resp);
                break;
        case SMC_LLC_ADD_LINK:
@@ -1706,7 +1706,7 @@ static void smc_llc_testlink_work(struct work_struct *work)
        u8 user_data[16] = { 0 };
        int rc;
 
-       if (link->state != SMC_LNK_ACTIVE)
+       if (!smc_link_active(link))
                return;         /* don't reschedule worker */
        expire_time = link->wr_rx_tstamp + link->llc_testlink_time;
        if (time_is_after_jiffies(expire_time)) {
@@ -1718,7 +1718,7 @@ static void smc_llc_testlink_work(struct work_struct *work)
        /* receive TEST LINK response over RoCE fabric */
        rc = wait_for_completion_interruptible_timeout(&link->llc_testlink_resp,
                                                       SMC_LLC_WAIT_TIME);
-       if (link->state != SMC_LNK_ACTIVE)
+       if (!smc_link_active(link))
                return;         /* link state changed */
        if (rc <= 0) {
                smcr_link_down_cond_sched(link);