[PATCH 1/1 Version 2.0] PCI: allocate essential resources beforereserving hotplug resources
From: Ram Pai
Date: Tue Jan 18 2011 - 16:32:19 EST
PCI: pre-allocate additional resources to devices
only after successful allocation of essential resources.
Linux tries to pre-allocate minimal resources to hotplug
bridges. This works fine as long as there are enough
resources to satisfy all other genuine resource
requirements. However if enough resources are not
available to satisfy any of these nice-to-have
pre-allocations, the resource-allocator reports errors
and returns failure.
This patch distinguishes between must-have resource from
nice-to-have resource. Any failure to allocate
nice-to-have resources are ignored.
This behavior can be particularly useful to trigger
automatic reallocation, if the OS discovers genuine
resource allocation conflicts or genuine unallocated
resource requests caused by buggy allocation behavior
of the native BIOS/uEFI.
https://bugzilla.kernel.org/show_bug.cgi?id=15960
captures the movitation behind the patch.
This patch is verified to resolve the above bug.
Signed-off-by: Ram Pai <linuxram@xxxxxxxxxx>
diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index 66cb8f4..5b0fb2f 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -91,7 +91,39 @@ static void __dev_sort_resources(struct pci_dev *dev,
pdev_sort_resources(dev, head);
}
-static void __assign_resources_sorted(struct resource_list *head,
+static inline void reset_resource(struct resource *res)
+{
+ res->start = 0;
+ res->end = 0;
+ res->add_size = 0;
+ res->flags = 0;
+}
+
+static void adjust_resources_sorted(struct resource_list *head)
+{
+ struct resource *res;
+ struct resource_list *list, *tmp;
+ int idx;
+
+ for (list = head->next; list;) {
+ res = list->res;
+ idx = res - &list->dev->resource[0];
+
+ if (!resource_size(res) && res->add_size) {
+ res->end = res->start + res->add_size - 1;
+ if(pci_assign_resource(list->dev, idx))
+ reset_resource(res);
+ } else if (res->add_size) {
+ adjust_resource(res, res->start,
+ resource_size(res) + res->add_size);
+ }
+ tmp = list;
+ list = list->next;
+ kfree(tmp);
+ }
+}
+
+static void assign_requested_resources_sorted(struct resource_list *head,
struct resource_list_x *fail_head)
{
struct resource *res;
@@ -102,7 +134,7 @@ static void __assign_resources_sorted(struct resource_list *head,
res = list->res;
idx = res - &list->dev->resource[0];
- if (pci_assign_resource(list->dev, idx)) {
+ if (resource_size(res) && pci_assign_resource(list->dev, idx)) {
if (fail_head && !pci_is_root_bus(list->dev->bus)) {
/*
* if the failed res is for ROM BAR, and it will
@@ -112,16 +144,24 @@ static void __assign_resources_sorted(struct resource_list *head,
(!(res->flags & IORESOURCE_ROM_ENABLE))))
add_to_failed_list(fail_head, list->dev, res);
}
- res->start = 0;
- res->end = 0;
- res->flags = 0;
+ reset_resource(res);
}
tmp = list;
list = list->next;
- kfree(tmp);
}
}
+static void __assign_resources_sorted(struct resource_list *head,
+ struct resource_list_x *fail_head)
+{
+ /* Satisfy the must-have resource requests */
+ assign_requested_resources_sorted(head, fail_head);
+
+ /* Try to satisfy any additional nice-to-have resource
+ requests */
+ adjust_resources_sorted(head);
+}
+
static void pdev_assign_resources_sorted(struct pci_dev *dev,
struct resource_list_x *fail_head)
{
@@ -404,15 +444,37 @@ static struct resource *find_free_bus_resource(struct pci_bus *bus, unsigned lon
return NULL;
}
+static resource_size_t calculate_iosize(resource_size_t size,
+ resource_size_t min_size,
+ resource_size_t size1,
+ resource_size_t old_size,
+ resource_size_t align)
+{
+ if (size < min_size)
+ size = min_size;
+ if (old_size == 1 )
+ old_size = 0;
+ /* To be fixed in 2.5: we should have sort of HAVE_ISA
+ flag in the struct pci_bus. */
+#if defined(CONFIG_ISA) || defined(CONFIG_EISA)
+ size = (size & 0xff) + ((size & ~0xffUL) << 2);
+#endif
+ size = ALIGN(size + size1, align);
+ if (size < old_size)
+ size = old_size;
+ return size;
+}
+
/* Sizing the IO windows of the PCI-PCI bridge is trivial,
since these windows have 4K granularity and the IO ranges
of non-bridge PCI devices are limited to 256 bytes.
We must be careful with the ISA aliasing though. */
-static void pbus_size_io(struct pci_bus *bus, resource_size_t min_size)
+static void pbus_size_io(struct pci_bus *bus, resource_size_t min_size,
+ resource_size_t add_size)
{
struct pci_dev *dev;
struct resource *b_res = find_free_bus_resource(bus, IORESOURCE_IO);
- unsigned long size = 0, size1 = 0, old_size;
+ unsigned long size = 0, size1 = 0;
if (!b_res)
return;
@@ -435,20 +497,14 @@ static void pbus_size_io(struct pci_bus *bus, resource_size_t min_size)
size1 += r_size;
}
}
- if (size < min_size)
- size = min_size;
- old_size = resource_size(b_res);
- if (old_size == 1)
- old_size = 0;
-/* To be fixed in 2.5: we should have sort of HAVE_ISA
- flag in the struct pci_bus. */
-#if defined(CONFIG_ISA) || defined(CONFIG_EISA)
- size = (size & 0xff) + ((size & ~0xffUL) << 2);
-#endif
- size = ALIGN(size + size1, 4096);
- if (size < old_size)
- size = old_size;
- if (!size) {
+
+ size = calculate_iosize(size, min_size, size1,
+ resource_size(b_res), 4096);
+ size1 = !add_size? size:
+ calculate_iosize(size, min_size+add_size, size1,
+ resource_size(b_res), 4096);
+
+ if (!size && !size1) {
if (b_res->start || b_res->end)
dev_info(&bus->self->dev, "disabling bridge window "
"%pR to [bus %02x-%02x] (unused)\n", b_res,
@@ -459,16 +515,35 @@ static void pbus_size_io(struct pci_bus *bus, resource_size_t min_size)
/* Alignment of the IO window is always 4K */
b_res->start = 4096;
b_res->end = b_res->start + size - 1;
+ b_res->add_size = size1-size;
b_res->flags |= IORESOURCE_STARTALIGN;
}
+
+static resource_size_t calculate_memsize(resource_size_t size,
+ resource_size_t min_size,
+ resource_size_t size1,
+ resource_size_t old_size,
+ resource_size_t align)
+{
+ if (size < min_size)
+ size = min_size;
+ if (old_size == 1 )
+ old_size = 0;
+ if (size < old_size)
+ size = old_size;
+ size = ALIGN(size + size1, align);
+ return size;
+}
+
/* Calculate the size of the bus and minimal alignment which
guarantees that all child resources fit in this size. */
static int pbus_size_mem(struct pci_bus *bus, unsigned long mask,
- unsigned long type, resource_size_t min_size)
+ unsigned long type, resource_size_t min_size,
+ resource_size_t add_size)
{
struct pci_dev *dev;
- resource_size_t min_align, align, size, old_size;
+ resource_size_t min_align, align, size, size1;
resource_size_t aligns[12]; /* Alignments from 1Mb to 2Gb */
int order, max_order;
struct resource *b_res = find_free_bus_resource(bus, type);
@@ -516,13 +591,6 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask,
mem64_mask &= r->flags & IORESOURCE_MEM_64;
}
}
- if (size < min_size)
- size = min_size;
- old_size = resource_size(b_res);
- if (old_size == 1)
- old_size = 0;
- if (size < old_size)
- size = old_size;
align = 0;
min_align = 0;
@@ -537,8 +605,13 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask,
min_align = align1 >> 1;
align += aligns[order];
}
- size = ALIGN(size, min_align);
- if (!size) {
+
+ size = calculate_memsize(size, min_size, 0, resource_size(b_res), align);
+ size1 = !add_size ? size :
+ calculate_memsize(size, min_size+add_size, 0,
+ resource_size(b_res), align);
+
+ if (!size && !size1) {
if (b_res->start || b_res->end)
dev_info(&bus->self->dev, "disabling bridge window "
"%pR to [bus %02x-%02x] (unused)\n", b_res,
@@ -548,8 +621,8 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask,
}
b_res->start = min_align;
b_res->end = size + min_align - 1;
- b_res->flags |= IORESOURCE_STARTALIGN;
- b_res->flags |= mem64_mask;
+ b_res->add_size = size1 - size;
+ b_res->flags |= IORESOURCE_STARTALIGN | mem64_mask;
return 1;
}
@@ -606,7 +679,7 @@ void __ref pci_bus_size_bridges(struct pci_bus *bus)
{
struct pci_dev *dev;
unsigned long mask, prefmask;
- resource_size_t min_mem_size = 0, min_io_size = 0;
+ 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;
@@ -637,11 +710,11 @@ void __ref pci_bus_size_bridges(struct pci_bus *bus)
case PCI_CLASS_BRIDGE_PCI:
pci_bridge_check_ranges(bus);
if (bus->self->is_hotplug_bridge) {
- min_io_size = pci_hotplug_io_size;
- min_mem_size = pci_hotplug_mem_size;
+ additional_io_size = pci_hotplug_io_size;
+ additional_mem_size = pci_hotplug_mem_size;
}
default:
- pbus_size_io(bus, min_io_size);
+ pbus_size_io(bus, 0, additional_io_size);
/* If the bridge supports prefetchable range, size it
separately. If it doesn't, or its prefetchable window
has already been allocated by arch code, try
@@ -649,11 +722,11 @@ void __ref pci_bus_size_bridges(struct pci_bus *bus)
resources. */
mask = IORESOURCE_MEM;
prefmask = IORESOURCE_MEM | IORESOURCE_PREFETCH;
- if (pbus_size_mem(bus, prefmask, prefmask, min_mem_size))
+ if (pbus_size_mem(bus, prefmask, prefmask, 0, additional_mem_size))
mask = prefmask; /* Success, size non-prefetch only. */
else
- min_mem_size += min_mem_size;
- pbus_size_mem(bus, mask, IORESOURCE_MEM, min_mem_size);
+ additional_mem_size += additional_mem_size;
+ pbus_size_mem(bus, mask, IORESOURCE_MEM, 0, additional_mem_size);
break;
}
}
diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index e9bb22c..70b4ae6 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -18,6 +18,7 @@
struct resource {
resource_size_t start;
resource_size_t end;
+ resource_size_t add_size; /* additional nice-to-have resource */
const char *name;
unsigned long flags;
struct resource *parent, *sibling, *child;
--
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