On Mon, May 06, 2013 at 04:15:29PM -0700, Yinghai Lu wrote:
> BenH reported that there is some assign unassigned resource problem
> in powerpc.
>
> It turns out after
> | commit 0c5be0cb0edfe3b5c4b62eac68aa2aa15ec681af
> | Date: Thu Feb 23 19:23:29 2012 -0800
> |
> | PCI: Retry on IORESOURCE_IO type allocations
>
> even the root bus does not have io port range, it will keep retrying
> to realloc with mmio.
>
> Current retry logic is : try with must+optional at first, and if
> it fails will try must then try to extend must with optional.
> That will fail as mmio-non-pref and mmio-pref for bridge will
> be next to each other. So we have no chance to extend mmio-non-pref.
>
> We should not fall into retry in this case, as root bus does
> not io port range.
>
> Before we do that we need to split pci_assign_unassiged_resource
> to every root bus, so we can stop early for root bus without ioport
> range, and still continue to retry on buses that do have ioport range.
>
> This will be become more often when we have x86 8 sockets or 32 sockets
> system, and those system will have one root bus per socket.
> They will have some root buses do not have ioport range.
>
> For the retry failing, we could allocate mmio-non-pref bottom-up
> and mmio-pref will be top-down, but that could not be material for v3.10.
If I understand correctly, this particular patch makes no functional
changes, so the changelog above should be saved for the patches that *do*
actually fix problems.
>
> Reported-by: Benjamin Herrenschmidt <b...@kernel.crashing.org>
> Signed-off-by: Yinghai Lu <ying...@kernel.org>
>
> ---
> drivers/pci/setup-bus.c | 101
> +++++++++++++++++++++++-------------------------
> 1 file changed, 49 insertions(+), 52 deletions(-)
>
> Index: linux-2.6/drivers/pci/setup-bus.c
> ===================================================================
> --- linux-2.6.orig/drivers/pci/setup-bus.c
> +++ linux-2.6/drivers/pci/setup-bus.c
> @@ -1315,21 +1315,6 @@ static int __init pci_bus_get_depth(stru
>
> return depth;
> }
> -static int __init pci_get_max_depth(void)
> -{
> - int depth = 0;
> - struct pci_bus *bus;
> -
> - list_for_each_entry(bus, &pci_root_buses, node) {
> - int ret;
> -
> - ret = pci_bus_get_depth(bus);
> - if (ret > depth)
> - depth = ret;
> - }
> -
> - return depth;
> -}
>
> /*
> * -1: undefined, will auto detect later
> @@ -1354,34 +1339,41 @@ void __init pci_realloc_get_opt(char *st
> else if (!strncmp(str, "on", 2))
> pci_realloc_enable = user_enabled;
> }
> -static bool __init pci_realloc_enabled(void)
> +static bool __init pci_realloc_enabled(enum enable_type enable)
> {
> - return pci_realloc_enable >= user_enabled;
> + return enable >= user_enabled;
> }
>
> -static void __init pci_realloc_detect(void)
> +static enum enable_type __init pci_realloc_detect(struct pci_bus *bus,
> + enum enable_type enable_local)
> {
> #if defined(CONFIG_PCI_IOV) && defined(CONFIG_PCI_REALLOC_ENABLE_AUTO)
> - struct pci_dev *dev = NULL;
> + struct pci_dev *dev;
>
> - if (pci_realloc_enable != undefined)
> - return;
> + if (enable_local != undefined)
> + return enable_local;
>
> - for_each_pci_dev(dev) {
> + list_for_each_entry(dev, &bus->devices, bus_list) {
> int i;
>
> for (i = PCI_IOV_RESOURCES; i <= PCI_IOV_RESOURCE_END; i++) {
> struct resource *r = &dev->resource[i];
>
> /* Not assigned, or rejected by kernel ? */
> - if (r->flags && !r->start) {
> - pci_realloc_enable = auto_enabled;
> -
> - return;
> - }
> + if (r->flags && !r->start)
> + return auto_enabled;
> }
> }
> +
> + list_for_each_entry(dev, &bus->devices, bus_list) {
> + struct pci_bus *child = dev->subordinate;
> +
> + if (child &&
> + pci_realloc_detect(child, enable_local) == auto_enabled)
> + return auto_enabled;
> + }
This uses recursion and basically does the same thing as pci_walk_bus().
I think it will be clearer if you make it look something like this:
static int count_unassigned_resources(struct pci_dev *dev, void *data)
{
int *count = data;
for (i = PCI_IOV_RESOURCES; ...)
if (r->flags && !r->start)
*count++;
return 0;
}
static pci_realloc_detect(struct pci_bus *bus, ... enable_local)
{
int unassigned;
if (enable_local != undefined)
return enable_local;
unassigned = 0;
pci_walk_bus(bus, count_unassigned_resources, &unassigned);
if (unassigned)
return auto_enabled;
return enable_local;
}
> #endif
> + return enable_local;
> }
>
> /*
> @@ -1389,10 +1381,9 @@ static void __init pci_realloc_detect(vo
> * second and later try will clear small leaf bridge res
> * will stop till to the max deepth if can not find good one
> */
> -void __init
> -pci_assign_unassigned_resources(void)
> +static void __init
> +pci_assign_unassigned_root_bus_resources(struct pci_bus *bus)
> {
> - struct pci_bus *bus;
> LIST_HEAD(realloc_head); /* list of resources that
> want additional resources */
> struct list_head *add_list = NULL;
> @@ -1403,15 +1394,17 @@ pci_assign_unassigned_resources(void)
> unsigned long type_mask = IORESOURCE_IO | IORESOURCE_MEM |
> IORESOURCE_PREFETCH;
> int pci_try_num = 1;
> + enum enable_type enable_local;
>
> /* don't realloc if asked to do so */
> - pci_realloc_detect();
> - if (pci_realloc_enabled()) {
> - int max_depth = pci_get_max_depth();
> + enable_local = pci_realloc_detect(bus, pci_realloc_enable);
> + if (pci_realloc_enabled(enable_local)) {
> + int max_depth = pci_bus_get_depth(bus);
>
> pci_try_num = max_depth + 1;
> - printk(KERN_DEBUG "PCI: max bus depth: %d pci_try_num: %d\n",
> - max_depth, pci_try_num);
> + dev_printk(KERN_DEBUG, &bus->dev,
> + "max bus depth: %d pci_try_num: %d\n",
> + max_depth, pci_try_num);
> }
>
> again:
> @@ -1423,12 +1416,10 @@ again:
> add_list = &realloc_head;
> /* Depth first, calculate sizes and alignments of all
> subordinate buses. */
> - list_for_each_entry(bus, &pci_root_buses, node)
> - __pci_bus_size_bridges(bus, add_list);
> + __pci_bus_size_bridges(bus, add_list);
>
> /* Depth last, allocate resources and update the hardware. */
> - list_for_each_entry(bus, &pci_root_buses, node)
> - __pci_bus_assign_resources(bus, add_list, &fail_head);
> + __pci_bus_assign_resources(bus, add_list, &fail_head);
> if (add_list)
> BUG_ON(!list_empty(add_list));
> tried_times++;
> @@ -1438,17 +1429,17 @@ again:
> goto enable_and_dump;
>
> if (tried_times >= pci_try_num) {
> - if (pci_realloc_enable == undefined)
> - printk(KERN_INFO "Some PCI device resources are
> unassigned, try booting with pci=realloc\n");
> - else if (pci_realloc_enable == auto_enabled)
> - printk(KERN_INFO "Automatically enabled pci realloc, if
> you have problem, try booting with pci=realloc=off\n");
> + if (enable_local == undefined)
> + dev_info(&bus->dev, "Some PCI device resources are
> unassigned, try booting with pci=realloc\n");
> + else if (enable_local == auto_enabled)
> + dev_info(&bus->dev, "Automatically enabled pci realloc,
> if you have problem, try booting with pci=realloc=off\n");
I think you can add enable_local and the pci_realloc_enabled() parameter
in a separate patch. That will remove distractions from the main patch.
>
> free_list(&fail_head);
> goto enable_and_dump;
> }
>
> - printk(KERN_DEBUG "PCI: No. %d try to assign unassigned res\n",
> - tried_times + 1);
> + dev_printk(KERN_DEBUG, &bus->dev,
> + "No. %d try to assign unassigned res\n", tried_times + 1);
>
> /* third times and later will not check if it is leaf */
> if ((tried_times + 1) > 2)
> @@ -1458,12 +1449,11 @@ again:
> * Try to release leaf bridge's resources that doesn't fit resource of
> * child device under that bridge
> */
> - list_for_each_entry(fail_res, &fail_head, list) {
> - bus = fail_res->dev->bus;
> - pci_bus_release_bridge_resources(bus,
> + list_for_each_entry(fail_res, &fail_head, list)
> + pci_bus_release_bridge_resources(fail_res->dev->bus,
This change is gratuitous and distracting. Please move it to a
separate patch.
> fail_res->flags & type_mask,
> rel_type);
> - }
> +
> /* restore size and flags */
> list_for_each_entry(fail_res, &fail_head, list) {
> struct resource *res = fail_res->res;
> @@ -1480,12 +1470,19 @@ again:
>
> enable_and_dump:
> /* Depth last, update the hardware. */
> - list_for_each_entry(bus, &pci_root_buses, node)
> - pci_enable_bridges(bus);
> + pci_enable_bridges(bus);
>
> /* dump the resource on buses */
> + pci_bus_dump_resources(bus);
> +}
> +
> +void __init
> +pci_assign_unassigned_resources(void)
> +{
> + struct pci_bus *bus;
> +
> list_for_each_entry(bus, &pci_root_buses, node)
> - pci_bus_dump_resources(bus);
> + pci_assign_unassigned_root_bus_resources(bus);
> }
>
> void pci_assign_unassigned_bridge_resources(struct pci_dev *bridge)
I think this should be split up into something like the following patches
so we can see what's going on here:
- Remove "bus" temporary when calling pci_bus_release_bridge_resources()
- Add pci_realloc_enabled() parameter and enable_local
- Add pci_realloc_detect() parameters. The "bus" parameter is
ignored for now.
- Change pci_realloc_detect() to iterate over pci_root_buses and
call pci_walk_bus() to find any unassigned resources instead of
using for_each_pci_dev().
- Split pci_assign_unassigned_resources() into iterating over
pci_root_buses and calling pci_assign_unassigned_root_bus_resources(bus).
Change pci_realloc_detect() to only walk the supplied bus instead
of everything in pci_root_buses. This will be basically just removing
list_for_each_entry(bus, &pci_root_buses, node) loops.
Bjorn
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