Re: Linux 2.6.27-rc5: System boot regression caused by commit a2bd7274b47124d2fc4dfdb8c0591f545ba749dd

Yinghai Lu
2008-08-31T00:16:32Z

[-- Attachment #1: Type: text/plain, Size: 1269 bytes --]

> So I decided to try applying the patches against the tree as it was
> before bef69ea0...:
>
> =================================
> $ git checkout -f HEAD^
> Note: moving to "HEAD^" which isn't a local branch
> If you want to create a new branch from this checkout, you may do so
> (now or later) by using -b with the checkout command again. Example:
> git checkout -b <new_branch_name>
> HEAD is now at 00aeb42... Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6
>
> $ git apply --verbose --check ../split_e820_reserve.patch
> Checking patch arch/x86/kernel/e820.c...
> Checking patch arch/x86/pci/i386.c...
> Checking patch include/asm-x86/e820.h...
>
> $ git apply --verbose ../split_e820_reserve.patch
> Checking patch arch/x86/kernel/e820.c...
> Checking patch arch/x86/pci/i386.c...
> Checking patch include/asm-x86/e820.h...
> Applied patch arch/x86/kernel/e820.c cleanly.
> Applied patch arch/x86/pci/i386.c cleanly.
> Applied patch include/asm-x86/e820.h cleanly.
>
> $ git apply --verbose --check ../split_e820_reserve_xx1.patch
> Checking patch arch/x86/kernel/e820.c...
> Checking patch include/linux/ioport.h...
> Checking patch kernel/resource.c...

please use split_e820_reserve_xx2.patch instead...

Thanks

YH

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #2: split_e820_reserve_xx2.patch --]
[-- Type: text/x-patch; name=split_e820_reserve_xx2.patch, Size: 5127 bytes --]

From: Yinghai Lu <yhlu.kernel@gmail.com>
Subject: [PATCH] x86: split e820 reserved entries record to late v4 - fix v6

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@gmail.com>

---
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);

/**