bnx2x: Barriers for the compiler

To make sure no swapping are made by the compiler, changed HAS_WORK to inline
functions and added all the necessary barriers

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

1 files changed, 26 insertions, 11 deletions

diff --git a/drivers/net/bnx2x_main.c b/drivers/net/bnx2x_main.c
index dc05e37c581d..3236527477a3 100644
--- a/drivers/net/bnx2x_main.c
+++ b/drivers/net/bnx2x_main.c
@@ -733,6 +733,17 @@ static u16 bnx2x_ack_int(struct bnx2x *bp)
  * fast path service functions
  */
 
+static inline int bnx2x_has_tx_work(struct bnx2x_fastpath *fp)
+{
+        u16 tx_cons_sb;
+
+        /* Tell compiler that status block fields can change */
+        barrier();
+        tx_cons_sb = le16_to_cpu(*fp->tx_cons_sb);
+        return ((fp->tx_pkt_prod != tx_cons_sb) ||
+                (fp->tx_pkt_prod != fp->tx_pkt_cons));
+}
+
 /* free skb in the packet ring at pos idx
  * return idx of last bd freed
  */
@@ -6693,7 +6704,7 @@ static int bnx2x_nic_unload(struct bnx2x *bp, int unload_mode)
 
                 cnt = 1000;
                 smp_rmb();
-                while (BNX2X_HAS_TX_WORK(fp)) {
+                while (bnx2x_has_tx_work(fp)) {
 
                         bnx2x_tx_int(fp, 1000);
                         if (!cnt) {
@@ -9281,6 +9292,18 @@ static int bnx2x_set_power_state(struct bnx2x *bp, pci_power_t state)
         return 0;
 }
 
+static inline int bnx2x_has_rx_work(struct bnx2x_fastpath *fp)
+{
+        u16 rx_cons_sb;
+
+        /* Tell compiler that status block fields can change */
+        barrier();
+        rx_cons_sb = le16_to_cpu(*fp->rx_cons_sb);
+        if ((rx_cons_sb & MAX_RCQ_DESC_CNT) == MAX_RCQ_DESC_CNT)
+                rx_cons_sb++;
+        return (fp->rx_comp_cons != rx_cons_sb);
+}
+
 /*
  * net_device service functions
  */
@@ -9291,7 +9314,6 @@ static int bnx2x_poll(struct napi_struct *napi, int budget)
                                                  napi);
         struct bnx2x *bp = fp->bp;
         int work_done = 0;
-        u16 rx_cons_sb;
 
 #ifdef BNX2X_STOP_ON_ERROR
         if (unlikely(bp->panic))
@@ -9304,19 +9326,12 @@ static int bnx2x_poll(struct napi_struct *napi, int budget)
 
         bnx2x_update_fpsb_idx(fp);
 
-        if (BNX2X_HAS_TX_WORK(fp))
+        if (bnx2x_has_tx_work(fp))
                 bnx2x_tx_int(fp, budget);
 
-        rx_cons_sb = le16_to_cpu(*fp->rx_cons_sb);
-        if ((rx_cons_sb & MAX_RCQ_DESC_CNT) == MAX_RCQ_DESC_CNT)
-                rx_cons_sb++;
-        if (BNX2X_HAS_RX_WORK(fp))
+        if (bnx2x_has_rx_work(fp))
                 work_done = bnx2x_rx_int(fp, budget);
-
         rmb(); /* BNX2X_HAS_WORK() reads the status block */
-        rx_cons_sb = le16_to_cpu(*fp->rx_cons_sb);
-        if ((rx_cons_sb & MAX_RCQ_DESC_CNT) == MAX_RCQ_DESC_CNT)
-                rx_cons_sb++;
 
         /* must not complete if we consumed full budget */
         if ((work_done < budget) && !BNX2X_HAS_WORK(fp)) {