bnx2x: fix memory barriers

Signed-off-by: Dmitry Kravkov <dmitry@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/bnx2x/bnx2x_main.c b/drivers/net/bnx2x/bnx2x_main.c
index 7a89182..e4dea11 100644 (file)
--- a/drivers/net/bnx2x/bnx2x_main.c
+++ b/drivers/net/bnx2x/bnx2x_main.c
@@ -2984,8 +2984,12 @@ static inline void bnx2x_sp_prod_update(struct bnx2x *bp)
 {
        int func = BP_FUNC(bp);
 
-       /* Make sure that BD data is updated before writing the producer */
-       wmb();
+       /*
+        * Make sure that BD data is updated before writing the producer:
+        * BD data is written to the memory, the producer is read from the
+        * memory, thus we need a full memory barrier to ensure the ordering.
+        */
+       mb();
 
        REG_WR16(bp, BAR_XSTRORM_INTMEM + XSTORM_SPQ_PROD_OFFSET(func),
                 bp->spq_prod_idx);

diff --git a/drivers/net/bnx2x/bnx2x_sp.c b/drivers/net/bnx2x/bnx2x_sp.c
index 5a213e4..cce87d5 100644 (file)
--- a/drivers/net/bnx2x/bnx2x_sp.c
+++ b/drivers/net/bnx2x/bnx2x_sp.c
@@ -1563,8 +1563,13 @@ static int bnx2x_execute_vlan_mac(struct bnx2x *bp,
                                idx++;
                }
 
-               /* Commit the data writes towards the memory */
-               mb();
+               /*
+                *  No need for an explicit memory barrier here as long we would
+                *  need to ensure the ordering of writing to the SPQ element
+                *  and updating of the SPQ producer which involves a memory
+                *  read and we will have to put a full memory barrier there
+                *  (inside bnx2x_sp_post()).
+                */
 
                rc = bnx2x_sp_post(bp, o->ramrod_cmd, r->cid,
                                   U64_HI(r->rdata_mapping),
@@ -2224,8 +2229,13 @@ static int bnx2x_set_rx_mode_e2(struct bnx2x *bp,
                         data->header.rule_cnt, p->rx_accept_flags,
                         p->tx_accept_flags);
 
-       /* Commit writes towards the memory before sending a ramrod */
-       mb();
+       /*
+        *  No need for an explicit memory barrier here as long we would
+        *  need to ensure the ordering of writing to the SPQ element
+        *  and updating of the SPQ producer which involves a memory
+        *  read and we will have to put a full memory barrier there
+        *  (inside bnx2x_sp_post()).
+        */
 
        /* Send a ramrod */
        rc = bnx2x_sp_post(bp, RAMROD_CMD_ID_ETH_FILTER_RULES, p->cid,
@@ -2918,16 +2928,22 @@ static int bnx2x_mcast_setup_e2(struct bnx2x *bp,
        if (!o->total_pending_num)
                bnx2x_mcast_refresh_registry_e2(bp, o);
 
-       /* Commit writes towards the memory before sending a ramrod */
-       mb();
-
-       /* If CLEAR_ONLY was requested - don't send a ramrod and clear
+       /*
+        * If CLEAR_ONLY was requested - don't send a ramrod and clear
         * RAMROD_PENDING status immediately.
         */
        if (test_bit(RAMROD_DRV_CLR_ONLY, &p->ramrod_flags)) {
                raw->clear_pending(raw);
                return 0;
        } else {
+               /*
+                *  No need for an explicit memory barrier here as long we would
+                *  need to ensure the ordering of writing to the SPQ element
+                *  and updating of the SPQ producer which involves a memory
+                *  read and we will have to put a full memory barrier there
+                *  (inside bnx2x_sp_post()).
+                */
+
                /* Send a ramrod */
                rc = bnx2x_sp_post(bp, RAMROD_CMD_ID_ETH_MULTICAST_RULES,
                                   raw->cid, U64_HI(raw->rdata_mapping),
@@ -3404,16 +3420,22 @@ static int bnx2x_mcast_setup_e1(struct bnx2x *bp,
        if (rc)
                return rc;
 
-       /* Commit writes towards the memory before sending a ramrod */
-       mb();
-
-       /* If CLEAR_ONLY was requested - don't send a ramrod and clear
+       /*
+        * If CLEAR_ONLY was requested - don't send a ramrod and clear
         * RAMROD_PENDING status immediately.
         */
        if (test_bit(RAMROD_DRV_CLR_ONLY, &p->ramrod_flags)) {
                raw->clear_pending(raw);
                return 0;
        } else {
+               /*
+                *  No need for an explicit memory barrier here as long we would
+                *  need to ensure the ordering of writing to the SPQ element
+                *  and updating of the SPQ producer which involves a memory
+                *  read and we will have to put a full memory barrier there
+                *  (inside bnx2x_sp_post()).
+                */
+
                /* Send a ramrod */
                rc = bnx2x_sp_post(bp, RAMROD_CMD_ID_ETH_SET_MAC, raw->cid,
                                   U64_HI(raw->rdata_mapping),
@@ -4038,8 +4060,13 @@ static int bnx2x_setup_rss(struct bnx2x *bp,
                data->capabilities |= ETH_RSS_UPDATE_RAMROD_DATA_UPDATE_RSS_KEY;
        }
 
-       /* Commit writes towards the memory before sending a ramrod */
-       mb();
+       /*
+        *  No need for an explicit memory barrier here as long we would
+        *  need to ensure the ordering of writing to the SPQ element
+        *  and updating of the SPQ producer which involves a memory
+        *  read and we will have to put a full memory barrier there
+        *  (inside bnx2x_sp_post()).
+        */
 
        /* Send a ramrod */
        rc = bnx2x_sp_post(bp, RAMROD_CMD_ID_ETH_RSS_UPDATE, r->cid,
@@ -4505,7 +4532,13 @@ static inline int bnx2x_q_send_setup_e1x(struct bnx2x *bp,
        /* Fill the ramrod data */
        bnx2x_q_fill_setup_data_cmn(bp, params, rdata);
 
-       mb();
+       /*
+        *  No need for an explicit memory barrier here as long we would
+        *  need to ensure the ordering of writing to the SPQ element
+        *  and updating of the SPQ producer which involves a memory
+        *  read and we will have to put a full memory barrier there
+        *  (inside bnx2x_sp_post()).
+        */
 
        return bnx2x_sp_post(bp, ramrod, o->cids[BNX2X_PRIMARY_CID_INDEX],
                             U64_HI(data_mapping),
@@ -4528,6 +4561,13 @@ static inline int bnx2x_q_send_setup_e2(struct bnx2x *bp,
        bnx2x_q_fill_setup_data_cmn(bp, params, rdata);
        bnx2x_q_fill_setup_data_e2(bp, params, rdata);
 
+       /*
+        *  No need for an explicit memory barrier here as long we would
+        *  need to ensure the ordering of writing to the SPQ element
+        *  and updating of the SPQ producer which involves a memory
+        *  read and we will have to put a full memory barrier there
+        *  (inside bnx2x_sp_post()).
+        */
 
        return bnx2x_sp_post(bp, ramrod, o->cids[BNX2X_PRIMARY_CID_INDEX],
                             U64_HI(data_mapping),
@@ -4665,7 +4705,13 @@ static inline int bnx2x_q_send_update(struct bnx2x *bp,
        /* Fill the ramrod data */
        bnx2x_q_fill_update_data(bp, o, update_params, rdata);
 
-       mb();
+       /*
+        *  No need for an explicit memory barrier here as long we would
+        *  need to ensure the ordering of writing to the SPQ element
+        *  and updating of the SPQ producer which involves a memory
+        *  read and we will have to put a full memory barrier there
+        *  (inside bnx2x_sp_post()).
+        */
 
        return bnx2x_sp_post(bp, RAMROD_CMD_ID_ETH_CLIENT_UPDATE,
                             o->cids[cid_index], U64_HI(data_mapping),
@@ -5484,7 +5530,13 @@ static inline int bnx2x_func_send_start(struct bnx2x *bp,
        rdata->path_id       = BP_PATH(bp);
        rdata->network_cos_mode = start_params->network_cos_mode;
 
-       mb();
+       /*
+        *  No need for an explicit memory barrier here as long we would
+        *  need to ensure the ordering of writing to the SPQ element
+        *  and updating of the SPQ producer which involves a memory
+        *  read and we will have to put a full memory barrier there
+        *  (inside bnx2x_sp_post()).
+        */
 
        return bnx2x_sp_post(bp, RAMROD_CMD_ID_COMMON_FUNCTION_START, 0,
                             U64_HI(data_mapping),