bnx2: Free IRQ before freeing status block memory

When changing ring size, we free all memory including status block
memory.  If we're in INTA mode and sharing IRQ, the IRQ handler can
be called and it will reference the NULL status block pointer.

Because of the lockless design of the IRQ handler, there is no simple
way to synchronize and prevent this.  So we avoid this problem by
freeing the IRQ handler before freeing the status block memory.

Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/bnx2.c

@@ -6096,7 +6096,7 @@ bnx2_request_irq(struct bnx2 *bp)
 }
 
 static void
-bnx2_free_irq(struct bnx2 *bp)
+__bnx2_free_irq(struct bnx2 *bp)
 {
 	struct bnx2_irq *irq;
 	int i;
@@ -6107,6 +6107,13 @@ bnx2_free_irq(struct bnx2 *bp)
 			free_irq(irq->vector, &bp->bnx2_napi[i]);
 		irq->requested = 0;
 	}
+}
+
+static void
+bnx2_free_irq(struct bnx2 *bp)
+{
+
+	__bnx2_free_irq(bp);
 	if (bp->flags & BNX2_FLAG_USING_MSI)
 		pci_disable_msi(bp->pdev);
 	else if (bp->flags & BNX2_FLAG_USING_MSIX)
@@ -7092,6 +7099,7 @@ bnx2_change_ring_size(struct bnx2 *bp, u32 rx, u32 tx)
 
 		bnx2_netif_stop(bp, true);
 		bnx2_reset_chip(bp, BNX2_DRV_MSG_CODE_RESET);
+		__bnx2_free_irq(bp);
 		bnx2_free_skbs(bp);
 		bnx2_free_mem(bp);
 	}
@@ -7103,6 +7111,9 @@ bnx2_change_ring_size(struct bnx2 *bp, u32 rx, u32 tx)
 		int rc;
 
 		rc = bnx2_alloc_mem(bp);
+		if (!rc)
+			rc = bnx2_request_irq(bp);
+
 		if (!rc)
 			rc = bnx2_init_nic(bp, 0);