[Xen-devel] [PATCH] backport Linux changeset of bf4162bcf82ebc3258d6bc0ddd6453132abde72d

[Isaku Yamahata <yamahata@xxxxxxxxxxxxx>]

backport Linux changeset of bf4162bcf82ebc3258d6bc0ddd6453132abde72d

Without this patch, fakephp with reassigndev fails
to allocate memory resource.

Signed-off-by: Isaku Yamahata <yamahata@xxxxxxxxxxxxx>

commit bf4162bcf82ebc3258d6bc0ddd6453132abde72d
Author: Darrick J. Wong <djwong@xxxxxxxxxx>
Date:   Tue Nov 25 13:51:44 2008 -0800

    PCI hotplug: fakephp: Allocate PCI resources before adding the device
    
    For PCI devices, pci_bus_assign_resources() must be called to set up the
    pci_device->resource array before pci_bus_add_devices() can be called, else
    attempts to load drivers results in BAR collision errors where there are 
none.
    This is not done in fakephp, so devices can be "unplugged" but scanning the
    parent bus won't bring the devices back due to resource unallocation.  Move 
the
    pci_bus_add_device-calling logic into pci_rescan_bus and preface it with a 
call
    to pci_bus_assign_resources so that we only have to (re)allocate resources 
once
    per bus where a new device is found.
    
    Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
    Acked-by: Alex Chiang <achiang@xxxxxx>
    Signed-off-by: Jesse Barnes <jbarnes@xxxxxxxxxxxxxxxx>


diff --git a/drivers/pci/hotplug/fakephp.c b/drivers/pci/hotplug/fakephp.c
--- a/drivers/pci/hotplug/fakephp.c
+++ b/drivers/pci/hotplug/fakephp.c
@@ -171,12 +171,14 @@ static void remove_slot(struct dummy_slo
  *
  * @param temp   Device template. Should be set: bus and devfn.
  */
-static void pci_rescan_slot(struct pci_dev *temp)
+static int pci_rescan_slot(struct pci_dev *temp)
 {
        struct pci_bus *bus = temp->bus;
        struct pci_dev *dev;
        int func;
        u8 hdr_type;
+       int count = 0;
+
        if (!pci_read_config_byte(temp, PCI_HEADER_TYPE, &hdr_type)) {
                temp->hdr_type = hdr_type & 0x7f;
                if (!pci_find_slot(bus->number, temp->devfn)) {
@@ -185,13 +187,12 @@ static void pci_rescan_slot(struct pci_d
                                dbg("New device on %s function %x:%x\n",
                                        bus->name, temp->devfn >> 3,
                                        temp->devfn & 7);
-                               pci_bus_add_device(dev);
-                               add_slot(dev);
+                               count++;
                        }
                }
                /* multifunction device? */
                if (!(hdr_type & 0x80))
-                       return;
+                       return count;
 
                /* continue scanning for other functions */
                for (func = 1, temp->devfn++; func < 8; func++, temp->devfn++) {
@@ -205,12 +206,12 @@ static void pci_rescan_slot(struct pci_d
                                        dbg("New device on %s function %x:%x\n",
                                                bus->name, temp->devfn >> 3,
                                                temp->devfn & 7);
-                                       pci_bus_add_device(dev);
-                                       add_slot(dev);
+                                       count++;
                                }
                        }
                }
        }
+       return count;
 }
 
 
@@ -220,10 +221,11 @@ static void pci_rescan_slot(struct pci_d
  *
  * @param bus
  */
-static void pci_rescan_bus(const struct pci_bus *bus)
+static void pci_rescan_bus(struct pci_bus *bus)
 {
        unsigned int devfn;
        struct pci_dev *dev;
+       int found = 0;
        dev = kzalloc(sizeof(struct pci_dev), GFP_KERNEL);
        if (!dev)
                return;
@@ -232,7 +234,20 @@ static void pci_rescan_bus(const struct 
        dev->sysdata = bus->sysdata;
        for (devfn = 0; devfn < 0x100; devfn += 8) {
                dev->devfn = devfn;
-               pci_rescan_slot(dev);
+               found += pci_rescan_slot(dev);
+       }
+
+       if (found) {
+               struct pci_dev *tmp;
+               pci_bus_assign_resources(bus);
+               list_for_each_entry(tmp, &bus->devices, bus_list) {
+                       /* Skip already-added devices */
+                       if (!list_empty(&tmp->global_list))
+                               continue;
+                       pci_bus_add_device(tmp);
+                       add_slot(tmp);
+               }
+               pci_bus_add_devices(bus);
        }
        kfree(dev);
 }
@@ -242,7 +257,7 @@ static void pci_rescan_buses(const struc
 {
        const struct list_head *l;
        list_for_each(l,list) {
-               const struct pci_bus *b = pci_bus_b(l);
+               struct pci_bus *b = pci_bus_b(l);
                pci_rescan_bus(b);
                pci_rescan_buses(&b->children);
        }


-- 
yamahata

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