cxgb3: add memory barriers

Add memory barriers to fix crashes observed on newest PowerPC platforms.
The HW and driver state of the receive rings were getting out of sync.

Signed-off-by: Divy Le Ray <divy@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 12 insertions, 4 deletions

diff --git a/drivers/net/cxgb3/sge.c b/drivers/net/cxgb3/sge.c
index bdbd14727e4b..4cf9b7962afa 100644
--- a/drivers/net/cxgb3/sge.c
+++ b/drivers/net/cxgb3/sge.c
@@ -480,6 +480,7 @@ static inline void ring_fl_db(struct adapter *adap, struct sge_fl *q)
 {
         if (q->pend_cred >= q->credits / 4) {
                 q->pend_cred = 0;
+                wmb();
                 t3_write_reg(adap, A_SG_KDOORBELL, V_EGRCNTX(q->cntxt_id));
         }
 }
@@ -2282,11 +2283,14 @@ static int process_responses(struct adapter *adap, struct sge_qset *qs,
         while (likely(budget_left && is_new_response(r, q))) {
                 int packet_complete, eth, ethpad = 2, lro = qs->lro_enabled;
                 struct sk_buff *skb = NULL;
-                u32 len, flags = ntohl(r->flags);
-                __be32 rss_hi = *(const __be32 *)r,
-                       rss_lo = r->rss_hdr.rss_hash_val;
+                u32 len, flags;
+                __be32 rss_hi, rss_lo;
 
+                rmb();
                 eth = r->rss_hdr.opcode == CPL_RX_PKT;
+                rss_hi = *(const __be32 *)r;
+                rss_lo = r->rss_hdr.rss_hash_val;
+                flags = ntohl(r->flags);
 
                 if (unlikely(flags & F_RSPD_ASYNC_NOTIF)) {
                         skb = alloc_skb(AN_PKT_SIZE, GFP_ATOMIC);
@@ -2497,7 +2501,10 @@ static int process_pure_responses(struct adapter *adap, struct sge_qset *qs,
                         refill_rspq(adap, q, q->credits);
                         q->credits = 0;
                 }
-        } while (is_new_response(r, q) && is_pure_response(r));
+                if (!is_new_response(r, q))
+                        break;
+                rmb();
+        } while (is_pure_response(r));
 
         if (sleeping)
                 check_ring_db(adap, qs, sleeping);
@@ -2531,6 +2538,7 @@ static inline int handle_responses(struct adapter *adap, struct sge_rspq *q)
 
         if (!is_new_response(r, q))
                 return -1;
+        rmb();
         if (is_pure_response(r) && process_pure_responses(adap, qs, r) == 0) {
                 t3_write_reg(adap, A_SG_GTS, V_RSPQ(q->cntxt_id) |
                              V_NEWTIMER(q->holdoff_tmr) | V_NEWINDEX(q->cidx));