Commits 
881a8c120acf7ec09c90289e2996b7c70f51e996 and
efe1ec27837d6639eae82e1f5876910ba6433c3f corrects pci device matching in
only one way; it no longer oopses/crashes, despite hotplug is not solved
in these changes.
Whenever pci_find_device -> pci_get_device change is performed, also
pci_dev_get and pci_dev_put should be in most cases called to properly
handle hotplug.  This patch does exactly this thing -- increase refcount
to let kernel know, that we are using this piece of HW just now.
It affects moxa and rio char drivers.
Cc: <R.E.Wolff@BitWizard.nl>
Acked-by: Amit Gud <gud@eth.net>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
 typedef struct _moxa_pci_devinfo {
        ushort busNum;
        ushort devNum;
+       struct pci_dev *pdev;
 } moxa_pci_devinfo;
 
 typedef struct _moxa_board_conf {
        board->busType = MOXA_BUS_TYPE_PCI;
        board->pciInfo.busNum = p->bus->number;
        board->pciInfo.devNum = p->devfn >> 3;
+       board->pciInfo.pdev = p;
+       /* don't lose the reference in the next pci_get_device iteration */
+       pci_dev_get(p);
 
        return (0);
 }
        if (tty_unregister_driver(moxaDriver))
                printk("Couldn't unregister MOXA Intellio family serial driver\n");
        put_tty_driver(moxaDriver);
+
+       for (i = 0; i < MAX_BOARDS; i++)
+               if (moxa_boards[i].busType == MOXA_BUS_TYPE_PCI)
+                       pci_dev_put(moxa_boards[i].pciInfo.pdev);
+
        if (verbose)
                printk("Done\n");
 }
 
 **    the host.
 */
 struct Host {
+       struct pci_dev *pdev;
        unsigned char Type;             /* RIO_EISA, RIO_MCA, ... */
        unsigned char Ivec;             /* POLLED or ivec number */
        unsigned char Mode;             /* Control stuff */
 
                        rio_dprintk(RIO_DEBUG_PROBE, "Hmm Tested ok, uniqid = %x.\n", p->RIOHosts[p->RIONumHosts].UniqueNum);
 
                        fix_rio_pci(pdev);
+
+                       p->RIOHosts[p->RIONumHosts].pdev = pdev;
+                       pci_dev_get(pdev);
+
                        p->RIOLastPCISearch = 0;
                        p->RIONumHosts++;
                        found++;
                            ((readb(&p->RIOHosts[p->RIONumHosts].Unique[1]) & 0xFF) << 8) | ((readb(&p->RIOHosts[p->RIONumHosts].Unique[2]) & 0xFF) << 16) | ((readb(&p->RIOHosts[p->RIONumHosts].Unique[3]) & 0xFF) << 24);
                        rio_dprintk(RIO_DEBUG_PROBE, "Hmm Tested ok, uniqid = %x.\n", p->RIOHosts[p->RIONumHosts].UniqueNum);
 
+                       p->RIOHosts[p->RIONumHosts].pdev = pdev;
+                       pci_dev_get(pdev);
+
                        p->RIOLastPCISearch = 0;
                        p->RIONumHosts++;
                        found++;
                }
                /* It is safe/allowed to del_timer a non-active timer */
                del_timer(&hp->timer);
+               if (hp->Type == RIO_PCI)
+                       pci_dev_put(hp->pdev);
        }
 
        if (misc_deregister(&rio_fw_device) < 0) {