qed: Add sanity check for SIMD fastpath handler.

Avoid calling a SIMD fastpath handler if it is NULL. The check is needed
to handle an unlikely scenario where unsolicited interrupt is destined to
a PF in INTa mode.

Fixes: fe56b9e ("qed: Add module with basic common support")
Signed-off-by: Sudarsana Reddy Kalluru <Sudarsana.Kalluru@cavium.com>
Signed-off-by: Ariel Elior <ariel.elior@cavium.com>
Signed-off-by: Michal Kalderon <Michal.Kalderon@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/qlogic/qed/qed_main.c

@@ -567,8 +567,16 @@ static irqreturn_t qed_single_int(int irq, void *dev_instance)
  /* Fastpath interrupts */
  for (j = 0; j < 64; j++) {
  if ((0x2ULL << j) & status) {
- hwfn->simd_proto_handler[j].func(
- hwfn->simd_proto_handler[j].token);
+ struct qed_simd_fp_handler *p_handler =
+ &hwfn->simd_proto_handler[j];
+
+ if (p_handler->func)
+ p_handler->func(p_handler->token);
+ else
+ DP_NOTICE(hwfn,
+ "Not calling fastpath handler as it is NULL [handler #%d, status 0x%llx]\n",
+ j, status);
+
  status &= ~(0x2ULL << j);
  rc = IRQ_HANDLED;
  }