xen/pciback: Remove tons of dereferences

A little cleanup. No functional difference.
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>

drivers/xen/xen-pciback/pci_stub.c

@@ -631,10 +631,12 @@ static pci_ers_result_t common_process(struct pcistub_device *psdev,
 {
 	pci_ers_result_t res = result;
 	struct xen_pcie_aer_op *aer_op;
+	struct xen_pcibk_device *pdev = psdev->pdev;
+	struct xen_pci_sharedinfo *sh_info = pdev->sh_info;
 	int ret;
 
 	/*with PV AER drivers*/
-	aer_op = &(psdev->pdev->sh_info->aer_op);
+	aer_op = &(sh_info->aer_op);
 	aer_op->cmd = aer_cmd ;
 	/*useful for error_detected callback*/
 	aer_op->err = state;
@@ -655,36 +657,36 @@ static pci_ers_result_t common_process(struct pcistub_device *psdev,
 	* this flag to judge whether we need to check pci-front give aer
 	* service ack signal
 	*/
-	set_bit(_PCIB_op_pending, (unsigned long *)&psdev->pdev->flags);
+	set_bit(_PCIB_op_pending, (unsigned long *)&pdev->flags);
 
 	/*It is possible that a pcifront conf_read_write ops request invokes
 	* the callback which cause the spurious execution of wake_up.
 	* Yet it is harmless and better than a spinlock here
 	*/
 	set_bit(_XEN_PCIB_active,
-		(unsigned long *)&psdev->pdev->sh_info->flags);
+		(unsigned long *)&sh_info->flags);
 	wmb();
-	notify_remote_via_irq(psdev->pdev->evtchn_irq);
+	notify_remote_via_irq(pdev->evtchn_irq);
 
 	ret = wait_event_timeout(xen_pcibk_aer_wait_queue,
 				 !(test_bit(_XEN_PCIB_active, (unsigned long *)
-				 &psdev->pdev->sh_info->flags)), 300*HZ);
+				 &sh_info->flags)), 300*HZ);
 
 	if (!ret) {
 		if (test_bit(_XEN_PCIB_active,
-			(unsigned long *)&psdev->pdev->sh_info->flags)) {
+			(unsigned long *)&sh_info->flags)) {
 			dev_err(&psdev->dev->dev,
 				"pcifront aer process not responding!\n");
 			clear_bit(_XEN_PCIB_active,
-			  (unsigned long *)&psdev->pdev->sh_info->flags);
+			  (unsigned long *)&sh_info->flags);
 			aer_op->err = PCI_ERS_RESULT_NONE;
 			return res;
 		}
 	}
-	clear_bit(_PCIB_op_pending, (unsigned long *)&psdev->pdev->flags);
+	clear_bit(_PCIB_op_pending, (unsigned long *)&pdev->flags);
 
 	if (test_bit(_XEN_PCIF_active,
-		(unsigned long *)&psdev->pdev->sh_info->flags)) {
+		(unsigned long *)&sh_info->flags)) {
 		dev_dbg(&psdev->dev->dev,
 			"schedule pci_conf service in " DRV_NAME "\n");
 		xen_pcibk_test_and_schedule_op(psdev->pdev);