Re: [PATCH] x86: split e820 reserved entries record to late v4 - fix v6

[Yinghai Lu]

Adding to : Ivan..

On Sat, Aug 30, 2008 at 1:34 PM, Yinghai Lu <yhlu.kernel@xxxxxxxxx> wrote:
> try to insert_resource second time, by expand the resource...
>
> for case: e820 reserved entry is partially overlapped with bar res...
>
> hope it will never happen
>
> v2: according to Linus, add insert_resource_expand_to_fit, and change
>        __insert_resource to static without lock
>
> v3: use reserve_region_with_split() instead to hand overlapping
>        with test case by extend 0xe0000000 - 0xeffffff to 0xdd800000 -
>        get
>                e0000000-efffffff : PCI MMCONFIG 0
>                         e0000000-efffffff : reserved
>        in /proc/iomem
>        get
>                found conflict for reserved [dd800000, efffffff], try to reserve with split
>                    __reserve_region_with_split: (PCI Bus #80) [dd000000, ddffffff], res: (reserved) [dd800000, efffffff]
>                    __reserve_region_with_split: (PCI Bus #00) [de000000, dfffffff], res: (reserved) [de000000, efffffff]
>                initcall pci_subsys_init+0x0/0x121 returned 0 after 381 msecs
>        in dmesg
>
> v4: take out __insert_resource and insert_resource_expand_to_fit : Linus already check in.
>    use reserve_region_with_split at the first point
>    use const char *name
>
> v5: fix checking on overlapping
>
> v6: only reserve common area in conflict
>        so got sth in /proc/iomem
>                d8000000-dfffffff : PCI Bus #00
>                  dc000000-dfffffff : GART
>                    dc000000-dfffffff : reserved
>                e0000000-efffffff : PCI MMCONFIG 0
>                  e0000000-efffffff : reserved
>        when we have big range in e820
>                00000000dc000000-00000000f0000000 (reserved)
>
> Signed-off-by: Yinghai Lu <yhlu.kernel@xxxxxxxxx>
>
> ---
>  arch/x86/kernel/e820.c |    2 -
>  include/linux/ioport.h |    3 ++
>  kernel/resource.c      |   69 ++++++++++++++++++++++++++++++++++++++++++++++++-
>  3 files changed, 72 insertions(+), 2 deletions(-)
>
> Index: linux-2.6/arch/x86/kernel/e820.c
> ===================================================================
> --- linux-2.6.orig/arch/x86/kernel/e820.c
> +++ linux-2.6/arch/x86/kernel/e820.c
> @@ -1320,7 +1320,7 @@ void __init e820_reserve_resources_late(
>        res = e820_res;
>        for (i = 0; i < e820.nr_map; i++) {
>                if (!res->parent && res->end)
> -                       insert_resource(&iomem_resource, res);
> +                       reserve_region_with_split(&iomem_resource, res->start, res->end, res->name);
>                res++;
>        }
>  }
> Index: linux-2.6/include/linux/ioport.h
> ===================================================================
> --- linux-2.6.orig/include/linux/ioport.h
> +++ linux-2.6/include/linux/ioport.h
> @@ -108,6 +108,9 @@ extern struct resource iomem_resource;
>
>  extern int request_resource(struct resource *root, struct resource *new);
>  extern int release_resource(struct resource *new);
> +extern void reserve_region_with_split(struct resource *root,
> +                            resource_size_t start, resource_size_t end,
> +                            const char *name);
>  extern int insert_resource(struct resource *parent, struct resource *new);
>  extern void insert_resource_expand_to_fit(struct resource *root, struct resource *new);
>  extern int allocate_resource(struct resource *root, struct resource *new,
> Index: linux-2.6/kernel/resource.c
> ===================================================================
> --- linux-2.6.orig/kernel/resource.c
> +++ linux-2.6/kernel/resource.c
> @@ -512,10 +512,77 @@ int adjust_resource(struct resource *res
>        result = 0;
>
>  out:
> -       write_unlock(&resource_lock);
>        return result;
>  }
>
> +static void __init __reserve_region_with_split(struct resource *root,
> +               resource_size_t start, resource_size_t end,
> +               const char *name)
> +{
> +       struct resource *parent = root;
> +       struct resource *conflict;
> +       struct resource *res = kzalloc(sizeof(*res), GFP_KERNEL);
> +
> +       if (!res)
> +               return;
> +
> +       res->name = name;
> +       res->start = start;
> +       res->end = end;
> +       res->flags = IORESOURCE_BUSY;
> +
> +       for (;;) {
> +               conflict = __request_resource(parent, res);
> +               if (!conflict)
> +                       break;
> +               if (conflict != parent) {
> +                       parent = conflict;
> +                       if (!(conflict->flags & IORESOURCE_BUSY))
> +                               continue;
> +               }
> +
> +               /* Uhhuh, that didn't work out.. */
> +               kfree(res);
> +               res = NULL;
> +               break;
> +       }
> +
> +       if (!res) {
> +               printk(KERN_DEBUG "    __reserve_region_with_split: (%s) [%llx, %llx], res: (%s) [%llx, %llx]\n",
> +                        conflict->name, conflict->start, conflict->end,
> +                        name, start, end);
> +
> +               /* failed, split and try again */
> +
> +               /* conflict coverred whole area */
> +               if (conflict->start <= start && conflict->end >= end)
> +                       return;
> +
> +               if (conflict->start > start)
> +                       __reserve_region_with_split(root, start, conflict->start-1, name);
> +               if (!(conflict->flags & IORESOURCE_BUSY)) {
> +                       resource_size_t common_start, common_end;
> +
> +                       common_start = max(conflict->start, start);
> +                       common_end = min(conflict->end, end);
> +                       if (common_start < common_end)
> +                               __reserve_region_with_split(root, common_start, common_end, name);
> +               }
> +               if (conflict->end < end)
> +                       __reserve_region_with_split(root, conflict->end+1, end, name);
> +       }
> +
> +}
> +
> +void reserve_region_with_split(struct resource *root,
> +               resource_size_t start, resource_size_t end,
> +               const char *name)
> +{
> +       write_lock(&resource_lock);
> +       __reserve_region_with_split(root, start, end, name);
> +       write_unlock(&resource_lock);
> +}
> +
>  EXPORT_SYMBOL(adjust_resource);
>
>  /**
>
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