On Friday, January 14, 2011 11:19:15 am Ram Pai wrote: > PCI: reserve additional resources for hotplug bridges > only after all essential resources are allocated. > > Linux tries to reserve minimal resources for hotplug > bridges. This works fine as long as there are enough > resources to satisfy all other essential resource > requirements. However if enough resources are not > available to satisfy both the essential resources > and the reservation for hotplug resources, the > resource-allocator reports error and returns failure. > > This patch distinguishes between essential resources and > nice-to-have resources. 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 > requests caused by not-so-smart allocation behavior of > the native BIOS. > > https://bugzilla.kernel.org/show_bug.cgi?id=15960 > captures the details of the issue and the motivation > behind this patch. Please don't indent and right-justify the changelog. This is a PCI-specific issue, so I'm not comfortable adding add_size to struct resource. That penalizes all resource users while only helping PCI. Also, the struct resource lives forever, and the add_size information is only useful while we're configuring the bridge. Bjorn > Signed-off-by: Ram Pai <linuxram@xxxxxxxxxx> > > drivers/pci/setup-bus.c | 142 +++++++++++++++++++++++++++++++++++------------- > include/linux/ioport.h | 1 > 2 files changed, 105 insertions(+), 38 deletions(-) > > diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c > index 66cb8f4..76a7fb7 100644 > --- a/drivers/pci/setup-bus.c > +++ b/drivers/pci/setup-bus.c > @@ -91,7 +91,26 @@ static void __dev_sort_resources(struct pci_dev *dev, > pdev_sort_resources(dev, head); > } > > -static void __assign_resources_sorted(struct resource_list *head, > + > +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 (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; > @@ -114,14 +133,25 @@ static void __assign_resources_sorted(struct resource_list *head, > } > res->start = 0; > res->end = 0; > + res->add_size = 0; > res->flags = 0; > } > 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 +434,37 @@ 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 +487,16 @@ 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); > + if (add_size) > + size1 = calculate_iosize(size, min_size+add_size, size1, > + resource_size(b_res), 4096); > + else > + size1 = size; > + > + 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 +507,35 @@ 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 +583,6 @@ 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 +597,14 @@ 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); > + if (add_size) > + size1 = calculate_memsize(size, min_size+add_size, 0, resource_size(b_res), align); > + else > + size1 = size; > + > + 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 +614,8 @@ 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 +672,7 @@ 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 +703,11 @@ 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 +715,11 @@ 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..d00c61c 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; > const char *name; > unsigned long flags; > struct resource *parent, *sibling, *child; > -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
