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Subject[RFC PATCH v1 11/22] PCI: enhance PCI resource assignment logic to support PCI bus lock mechanism
Date
This patch enhances PCI resource assignemnt logic to support PCI bus lock
mechanism.

Signed-off-by: Jiang Liu <liuj97@gmail.com>
---
drivers/pci/setup-bus.c | 65 +++++++++++++++++++++++++++++++++++------------
1 file changed, 49 insertions(+), 16 deletions(-)

diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index 192172c..08bac37 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -47,6 +47,7 @@ static void free_list(struct list_head *head)

list_for_each_entry_safe(dev_res, tmp, head, list) {
list_del(&dev_res->list);
+ pci_dev_put(dev_res->dev);
kfree(dev_res);
}
}
@@ -73,7 +74,7 @@ static int add_to_list(struct list_head *head,
}

tmp->res = res;
- tmp->dev = dev;
+ tmp->dev = pci_dev_get(dev);
tmp->start = res->start;
tmp->end = res->end;
tmp->flags = res->flags;
@@ -93,6 +94,7 @@ static void remove_from_list(struct list_head *head,
list_for_each_entry_safe(dev_res, tmp, head, list) {
if (dev_res->res == res) {
list_del(&dev_res->list);
+ pci_dev_put(dev_res->dev);
kfree(dev_res);
break;
}
@@ -151,7 +153,7 @@ static void pdev_sort_resources(struct pci_dev *dev, struct list_head *head)
panic("pdev_sort_resources(): "
"kmalloc() failed!\n");
tmp->res = r;
- tmp->dev = dev;
+ tmp->dev = pci_dev_get(dev);

/* fallback is smallest one or list is empty*/
n = head;
@@ -257,6 +259,7 @@ static void reassign_resources_sorted(struct list_head *realloc_head,
}
out:
list_del(&add_res->list);
+ pci_dev_put(add_res->dev);
kfree(add_res);
}
}
@@ -982,15 +985,16 @@ handle_done:
;
}

-void __ref __pci_bus_size_bridges(struct pci_bus *bus,
+static void __ref __pci_bus_size_bridges(struct pci_bus *bus,
struct list_head *realloc_head)
{
struct pci_dev *dev;
+ struct pci_bus *b;
unsigned long mask, prefmask;
resource_size_t additional_mem_size = 0, additional_io_size = 0;

list_for_each_entry(dev, &bus->devices, bus_list) {
- struct pci_bus *b = dev->subordinate;
+ b = pci_lock_subordinate(dev, PCI_BUS_STATE_STOPPING - 1);
if (!b)
continue;

@@ -1004,6 +1008,8 @@ void __ref __pci_bus_size_bridges(struct pci_bus *bus,
__pci_bus_size_bridges(b, realloc_head);
break;
}
+
+ pci_bus_unlock(b);
}

/* The root bus? */
@@ -1063,7 +1069,7 @@ static void __ref __pci_bus_assign_resources(const struct pci_bus *bus,
pbus_assign_resources_sorted(bus, realloc_head, fail_head);

list_for_each_entry(dev, &bus->devices, bus_list) {
- b = dev->subordinate;
+ b = pci_lock_subordinate(dev, PCI_BUS_STATE_STOPPING - 1);
if (!b)
continue;

@@ -1084,6 +1090,8 @@ static void __ref __pci_bus_assign_resources(const struct pci_bus *bus,
"%04x:%02x\n", pci_domain_nr(b), b->number);
break;
}
+
+ pci_bus_unlock(b);
}
}

@@ -1098,11 +1106,11 @@ static void __ref __pci_bridge_assign_resources(const struct pci_dev *bridge,
struct list_head *fail_head)
{
struct pci_bus *b;
+ struct pci_dev *dev = (struct pci_dev *)bridge;

- pdev_assign_resources_sorted((struct pci_dev *)bridge,
- add_head, fail_head);
+ pdev_assign_resources_sorted(dev, add_head, fail_head);

- b = bridge->subordinate;
+ b = pci_lock_subordinate(dev, PCI_BUS_STATE_STOPPING - 1);
if (!b)
return;

@@ -1122,7 +1130,10 @@ static void __ref __pci_bridge_assign_resources(const struct pci_dev *bridge,
"%04x:%02x\n", pci_domain_nr(b), b->number);
break;
}
+
+ pci_bus_unlock(b);
}
+
static void pci_bridge_release_resources(struct pci_bus *bus,
unsigned long type)
{
@@ -1169,6 +1180,7 @@ enum release_type {
leaf_only,
whole_subtree,
};
+
/*
* try to release pci bridge resources that is from leaf bridge,
* so we can allocate big new one later
@@ -1190,9 +1202,14 @@ static void __ref pci_bus_release_bridge_resources(struct pci_bus *bus,
if ((dev->class >> 8) != PCI_CLASS_BRIDGE_PCI)
continue;

- if (rel_type == whole_subtree)
+ if (rel_type != whole_subtree)
+ continue;
+
+ if (pci_bus_lock_states(b, PCI_BUS_STATE_STOPPING - 1) > 0) {
pci_bus_release_bridge_resources(b, type,
whole_subtree);
+ pci_bus_unlock(b);
+ }
}

if (pci_is_root_bus(bus))
@@ -1253,6 +1270,7 @@ static int __init pci_bus_get_depth(struct pci_bus *bus)

return depth;
}
+
static int __init pci_get_max_depth(void)
{
int depth = 0;
@@ -1285,6 +1303,7 @@ enum enable_type {
};

static enum enable_type pci_realloc_enable __initdata = undefined;
+
void __init pci_realloc_get_opt(char *str)
{
if (!strncmp(str, "off", 3))
@@ -1292,6 +1311,7 @@ void __init pci_realloc_get_opt(char *str)
else if (!strncmp(str, "on", 2))
pci_realloc_enable = user_enabled;
}
+
static bool __init pci_realloc_enabled(void)
{
return pci_realloc_enable >= user_enabled;
@@ -1428,7 +1448,7 @@ enable_and_dump:

void pci_assign_unassigned_bridge_resources(struct pci_dev *bridge)
{
- struct pci_bus *parent = bridge->subordinate;
+ struct pci_bus *parent;
LIST_HEAD(add_list); /* list of resources that
want additional resources */
int tried_times = 0;
@@ -1438,6 +1458,10 @@ void pci_assign_unassigned_bridge_resources(struct pci_dev *bridge)
unsigned long type_mask = IORESOURCE_IO | IORESOURCE_MEM |
IORESOURCE_PREFETCH;

+ parent = pci_lock_subordinate(bridge, PCI_BUS_STATE_STOPPING - 1);
+ if (!parent)
+ return;
+
again:
__pci_bus_size_bridges(parent, &add_list);
__pci_bridge_assign_resources(bridge, &add_list, &fail_head);
@@ -1464,8 +1488,13 @@ again:
struct pci_bus *bus = fail_res->dev->bus;
unsigned long flags = fail_res->flags;

+ if (bus != parent && pci_bus_lock_states(bus,
+ PCI_BUS_STATE_STOPPING - 1) < 0)
+ continue;
pci_bus_release_bridge_resources(bus, flags & type_mask,
whole_subtree);
+ if (bus != parent)
+ pci_bus_unlock(bus);
}
/* restore size and flags */
list_for_each_entry(fail_res, &fail_head, list) {
@@ -1485,6 +1514,7 @@ enable_all:
retval = pci_reenable_device(bridge);
pci_set_master(bridge);
pci_enable_bridges(parent);
+ pci_bus_unlock(parent);
}
EXPORT_SYMBOL_GPL(pci_assign_unassigned_bridge_resources);

@@ -1502,19 +1532,22 @@ unsigned int __ref pci_rescan_bus(struct pci_bus *bus)
{
unsigned int max;
struct pci_dev *dev;
+ struct pci_bus *b;
LIST_HEAD(add_list); /* list of resources that
want additional resources */

max = pci_scan_child_bus(bus);

- down_read(&pci_bus_sem);
list_for_each_entry(dev, &bus->devices, bus_list)
if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE ||
- dev->hdr_type == PCI_HEADER_TYPE_CARDBUS)
- if (dev->subordinate)
- __pci_bus_size_bridges(dev->subordinate,
- &add_list);
- up_read(&pci_bus_sem);
+ dev->hdr_type == PCI_HEADER_TYPE_CARDBUS) {
+ b = pci_lock_subordinate(dev,
+ PCI_BUS_STATE_STOPPING - 1);
+ if (b) {
+ __pci_bus_size_bridges(b, &add_list);
+ pci_bus_unlock(b);
+ }
+ }
__pci_bus_assign_resources(bus, &add_list, NULL);
BUG_ON(!list_empty(&add_list));

--
1.7.9.5


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