[PATCH v5 0/4] resource: Use list_head to link sibling resource

[PATCH v5 0/4] resource: Use list_head to link sibling resource

[Baoquan He]

This patchset is doing:
1) Replace struct resource's sibling list from singly linked list to
list_head. Clearing out those pointer operation within singly linked
list for better code readability.
2) Based on list_head replacement, add a new function
walk_system_ram_res_rev() which can does reversed iteration on
iomem_resource's siblings.
3) Change kexec_file loading to search system RAM top down for kernel
loadin, using walk_system_ram_res_rev().

Note:
This patchset passed testing on my kvm guest, x86_64 arch with network
enabling. The thing we need pay attetion to is that a root resource's
child member need be initialized specifically with LIST_HEAD_INIT() if
statically defined or INIT_LIST_HEAD() for dynamically definition. Here
Just like we do for iomem_resource/ioport_resource, or the change in
get_pci_domain_busn_res().


Links of the old post (Boris pointed out that we should use
https://lkml.kernel.org/r/Message-ID, while it can't be opened from
my side, so paste all of them here.):
v4:
https://lkml.kernel.org/r/20180507063224.24229-1-bhe-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org
https://lkml.org/lkml/2018/5/7/36

v3:
https://lkml.kernel.org/r/20180419001848.3041-1-bhe-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org
https://lkml.org/lkml/2018/4/18/767

v2:
https://lkml.kernel.org/r/20180408024724.16812-1-bhe-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org
https://lkml.org/lkml/2018/4/7/169

v1:
https://lkml.kernel.org/r/20180322033722.9279-1-bhe-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org
https://lkml.org/lkml/2018/3/21/952

Changelog:
v4->v5:
  Add new patch 0001 to move duplicated reparent_resources() to
  kernel/resource.c to make it be shared by different ARCH-es.

  Fix several code bugs reported by test robot on ARCH powerpc and
  microblaze.
v3->v4:
  Fix several bugs test robot reported. Rewrite cover letter and patch
  log according to reviewer's comment.

v2->v3:
  Rename resource functions first_child() and sibling() to
  resource_first_chils() and resource_sibling(). Dan suggested this.

  Move resource_first_chils() and resource_sibling() to linux/ioport.h
  and make them as inline function. Rob suggested this. Accordingly add
  linux/list.h including in linux/ioport.h, please help review if this
  bring efficiency degradation or code redundancy.

  The change on struct resource {} bring two pointers of size increase,
  mention this in git log to make it more specifically, Rob suggested
  this.

v1->v2:
  Use list_head instead to link resource siblings. This is suggested by
  Andrew.

  Rewrite walk_system_ram_res_rev() after list_head is taken to link
  resouce siblings.

Baoquan He (4):
  resource: Move reparent_resources() to kernel/resource.c and make it
    public
  resource: Use list_head to link sibling resource
  resource: add walk_system_ram_res_rev()
  kexec_file: Load kernel at top of system RAM if required

 arch/arm/plat-samsung/pm-check.c            |   6 +-
 arch/microblaze/pci/pci-common.c            |  41 +----
 arch/powerpc/kernel/pci-common.c            |  39 +----
 arch/sparc/kernel/ioport.c                  |   2 +-
 arch/xtensa/include/asm/pci-bridge.h        |   4 +-
 drivers/eisa/eisa-bus.c                     |   2 +
 drivers/gpu/drm/drm_memory.c                |   3 +-
 drivers/gpu/drm/gma500/gtt.c                |   5 +-
 drivers/hv/vmbus_drv.c                      |  52 +++---
 drivers/input/joystick/iforce/iforce-main.c |   4 +-
 drivers/nvdimm/namespace_devs.c             |   6 +-
 drivers/nvdimm/nd.h                         |   5 +-
 drivers/of/address.c                        |   4 +-
 drivers/parisc/lba_pci.c                    |   4 +-
 drivers/pci/host/vmd.c                      |   8 +-
 drivers/pci/probe.c                         |   2 +
 drivers/pci/setup-bus.c                     |   2 +-
 include/linux/ioport.h                      |  21 ++-
 kernel/kexec_file.c                         |   2 +
 kernel/resource.c                           | 259 ++++++++++++++++++----------
 20 files changed, 244 insertions(+), 227 deletions(-)

-- 
2.13.6

[PATCH v5 3/4] resource: add walk_system_ram_res_rev()

[Baoquan He]

This function, being a variant of walk_system_ram_res() introduced in
commit 8c86e70acead ("resource: provide new functions to walk through
resources"), walks through a list of all the resources of System RAM
in reversed order, i.e., from higher to lower.

It will be used in kexec_file code.

Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
---
 include/linux/ioport.h |  3 +++
 kernel/resource.c      | 40 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 43 insertions(+)

diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index b7456ae889dd..066cc263e2cc 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -279,6 +279,9 @@ extern int
 walk_system_ram_res(u64 start, u64 end, void *arg,
 		    int (*func)(struct resource *, void *));
 extern int
+walk_system_ram_res_rev(u64 start, u64 end, void *arg,
+			int (*func)(struct resource *, void *));
+extern int
 walk_iomem_res_desc(unsigned long desc, unsigned long flags, u64 start, u64 end,
 		    void *arg, int (*func)(struct resource *, void *));
 
diff --git a/kernel/resource.c b/kernel/resource.c
index ef9a20b75234..3128ac938f38 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -23,6 +23,8 @@
 #include <linux/pfn.h>
 #include <linux/mm.h>
 #include <linux/resource_ext.h>
+#include <linux/string.h>
+#include <linux/vmalloc.h>
 #include <asm/io.h>
 
 
@@ -443,6 +445,44 @@ int walk_system_ram_res(u64 start, u64 end, void *arg,
 }
 
 /*
+ * This function, being a variant of walk_system_ram_res(), calls the @func
+ * callback against all memory ranges of type System RAM which are marked as
+ * IORESOURCE_SYSTEM_RAM and IORESOUCE_BUSY in reversed order, i.e., from
+ * higher to lower.
+ */
+int walk_system_ram_res_rev(u64 start, u64 end, void *arg,
+				int (*func)(struct resource *, void *))
+{
+	unsigned long flags;
+	struct resource *res;
+	int ret = -1;
+
+	flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
+
+	read_lock(&resource_lock);
+	list_for_each_entry_reverse(res, &iomem_resource.child, sibling) {
+		if (start >= end)
+			break;
+		if ((res->flags & flags) != flags)
+			continue;
+		if (res->desc != IORES_DESC_NONE)
+			continue;
+		if (res->end < start)
+			break;
+
+		if ((res->end >= start) && (res->start < end)) {
+			ret = (*func)(res, arg);
+			if (ret)
+				break;
+		}
+		end = res->start - 1;
+
+	}
+	read_unlock(&resource_lock);
+	return ret;
+}
+
+/*
  * This function calls the @func callback against all memory ranges, which
  * are ranges marked as IORESOURCE_MEM and IORESOUCE_BUSY.
  */
-- 
2.13.6

[PATCH v5 1/4] resource: Move reparent_resources() to kernel/resource.c and make it public

[Baoquan He]

reparent_resources() is duplicated in arch/microblaze/pci/pci-common.c
and arch/powerpc/kernel/pci-common.c, so move it to kernel/resource.c
so that it's shared. Later its code also need be updated using list_head
to replace singly linked list.

Signed-off-by: Baoquan He <bhe-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Cc: Michal Simek <monstr-pSz03upnqPeHXe+LvDLADg@public.gmane.org>
Cc: Benjamin Herrenschmidt <benh-XVmvHMARGAS8U2dJNN8I7kB+6BGkLq7r@public.gmane.org>
Cc: Paul Mackerras <paulus-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>
Cc: Michael Ellerman <mpe-Gsx/Oe8HsFggBc27wqDAHg@public.gmane.org>
---
v4->v5:
  Fix several code bugs reported by test robot on ARCH powerpc and
  microblaze.

v3->v4:
  Fix several bugs test robot reported. And change patch log.

v2->v3:
  Rename resource functions first_child() and sibling() to
  resource_first_chils() and resource_sibling(). Dan suggested this.

  Move resource_first_chils() and resource_sibling() to linux/ioport.h
  and make them as inline function. Rob suggested this. Accordingly add
  linux/list.h including in linux/ioport.h, please help review if this
  bring efficiency degradation or code redundancy.

  The change on struct resource {} bring two pointers of size increase,
  mention this in git log to make it more specifically, Rob suggested
  this.

 arch/microblaze/pci/pci-common.c | 37 -------------------------------------
 arch/powerpc/kernel/pci-common.c | 35 -----------------------------------
 include/linux/ioport.h           |  1 +
 kernel/resource.c                | 36 ++++++++++++++++++++++++++++++++++++
 4 files changed, 37 insertions(+), 72 deletions(-)

diff --git a/arch/microblaze/pci/pci-common.c b/arch/microblaze/pci/pci-common.c
index f34346d56095..7899bafab064 100644
--- a/arch/microblaze/pci/pci-common.c
+++ b/arch/microblaze/pci/pci-common.c
@@ -619,43 +619,6 @@ int pcibios_add_device(struct pci_dev *dev)
 EXPORT_SYMBOL(pcibios_add_device);
 
 /*
- * Reparent resource children of pr that conflict with res
- * under res, and make res replace those children.
- */
-static int __init reparent_resources(struct resource *parent,
-				     struct resource *res)
-{
-	struct resource *p, **pp;
-	struct resource **firstpp = NULL;
-
-	for (pp = &parent->child; (p = *pp) != NULL; pp = &p->sibling) {
-		if (p->end < res->start)
-			continue;
-		if (res->end < p->start)
-			break;
-		if (p->start < res->start || p->end > res->end)
-			return -1;	/* not completely contained */
-		if (firstpp == NULL)
-			firstpp = pp;
-	}
-	if (firstpp == NULL)
-		return -1;	/* didn't find any conflicting entries? */
-	res->parent = parent;
-	res->child = *firstpp;
-	res->sibling = *pp;
-	*firstpp = res;
-	*pp = NULL;
-	for (p = res->child; p != NULL; p = p->sibling) {
-		p->parent = res;
-		pr_debug("PCI: Reparented %s [%llx..%llx] under %s\n",
-			 p->name,
-			 (unsigned long long)p->start,
-			 (unsigned long long)p->end, res->name);
-	}
-	return 0;
-}
-
-/*
  *  Handle resources of PCI devices.  If the world were perfect, we could
  *  just allocate all the resource regions and do nothing more.  It isn't.
  *  On the other hand, we cannot just re-allocate all devices, as it would
diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
index fe9733ffffaa..926035bb378d 100644
--- a/arch/powerpc/kernel/pci-common.c
+++ b/arch/powerpc/kernel/pci-common.c
@@ -1088,41 +1088,6 @@ resource_size_t pcibios_align_resource(void *data, const struct resource *res,
 EXPORT_SYMBOL(pcibios_align_resource);
 
 /*
- * Reparent resource children of pr that conflict with res
- * under res, and make res replace those children.
- */
-static int reparent_resources(struct resource *parent,
-				     struct resource *res)
-{
-	struct resource *p, **pp;
-	struct resource **firstpp = NULL;
-
-	for (pp = &parent->child; (p = *pp) != NULL; pp = &p->sibling) {
-		if (p->end < res->start)
-			continue;
-		if (res->end < p->start)
-			break;
-		if (p->start < res->start || p->end > res->end)
-			return -1;	/* not completely contained */
-		if (firstpp == NULL)
-			firstpp = pp;
-	}
-	if (firstpp == NULL)
-		return -1;	/* didn't find any conflicting entries? */
-	res->parent = parent;
-	res->child = *firstpp;
-	res->sibling = *pp;
-	*firstpp = res;
-	*pp = NULL;
-	for (p = res->child; p != NULL; p = p->sibling) {
-		p->parent = res;
-		pr_debug("PCI: Reparented %s %pR under %s\n",
-			 p->name, p, res->name);
-	}
-	return 0;
-}
-
-/*
  *  Handle resources of PCI devices.  If the world were perfect, we could
  *  just allocate all the resource regions and do nothing more.  It isn't.
  *  On the other hand, we cannot just re-allocate all devices, as it would
diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index da0ebaec25f0..dfdcd0bfe54e 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -192,6 +192,7 @@ extern int allocate_resource(struct resource *root, struct resource *new,
 struct resource *lookup_resource(struct resource *root, resource_size_t start);
 int adjust_resource(struct resource *res, resource_size_t start,
 		    resource_size_t size);
+int reparent_resources(struct resource *parent, struct resource *res);
 resource_size_t resource_alignment(struct resource *res);
 static inline resource_size_t resource_size(const struct resource *res)
 {
diff --git a/kernel/resource.c b/kernel/resource.c
index 30e1bc68503b..5e7c56d5d838 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -983,6 +983,42 @@ int adjust_resource(struct resource *res, resource_size_t start,
 }
 EXPORT_SYMBOL(adjust_resource);
 
+/*
+ * Reparent resource children of pr that conflict with res
+ * under res, and make res replace those children.
+ */
+static int reparent_resources(struct resource *parent,
+				     struct resource *res)
+{
+	struct resource *p, **pp;
+	struct resource **firstpp = NULL;
+
+	for (pp = &parent->child; (p = *pp) != NULL; pp = &p->sibling) {
+		if (p->end < res->start)
+			continue;
+		if (res->end < p->start)
+			break;
+		if (p->start < res->start || p->end > res->end)
+			return -1;	/* not completely contained */
+		if (firstpp == NULL)
+			firstpp = pp;
+	}
+	if (firstpp == NULL)
+		return -1;	/* didn't find any conflicting entries? */
+	res->parent = parent;
+	res->child = *firstpp;
+	res->sibling = *pp;
+	*firstpp = res;
+	*pp = NULL;
+	for (p = res->child; p != NULL; p = p->sibling) {
+		p->parent = res;
+		pr_debug("PCI: Reparented %s %pR under %s\n",
+			 p->name, p, res->name);
+	}
+	return 0;
+}
+EXPORT_SYMBOL(reparent_resources);
+
 static void __init __reserve_region_with_split(struct resource *root,
 		resource_size_t start, resource_size_t end,
 		const char *name)
-- 
2.13.6

Re: [PATCH v5 1/4] resource: Move reparent_resources() to kernel/resource.c and make it public

[kbuild test robot]

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Hi Baoquan,

I love your patch! Yet something to improve:

[auto build test ERROR on linus/master]
[also build test ERROR on v4.17 next-20180608]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Baoquan-He/resource-Use-list_head-to-link-sibling-resource/20180612-113600
config: i386-tinyconfig (attached as .config)
compiler: gcc-7 (Debian 7.3.0-16) 7.3.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

Note: the linux-review/Baoquan-He/resource-Use-list_head-to-link-sibling-resource/20180612-113600 HEAD 5545e79eef6387857faf41cdffa7be6b1f5d4efe builds fine.
      It only hurts bisectibility.

All errors (new ones prefixed by >>):

>> kernel/resource.c:990:12: error: static declaration of 'reparent_resources' follows non-static declaration
    static int reparent_resources(struct resource *parent,
               ^~~~~~~~~~~~~~~~~~
   In file included from kernel/resource.c:14:0:
   include/linux/ioport.h:195:5: note: previous declaration of 'reparent_resources' was here
    int reparent_resources(struct resource *parent, struct resource *res);
        ^~~~~~~~~~~~~~~~~~
   kernel/resource.c:990:12: warning: 'reparent_resources' defined but not used [-Wunused-function]
    static int reparent_resources(struct resource *parent,
               ^~~~~~~~~~~~~~~~~~

vim +/reparent_resources +990 kernel/resource.c

   985	
   986	/*
   987	 * Reparent resource children of pr that conflict with res
   988	 * under res, and make res replace those children.
   989	 */
 > 990	static int reparent_resources(struct resource *parent,
   991					     struct resource *res)
   992	{
   993		struct resource *p, **pp;
   994		struct resource **firstpp = NULL;
   995	
   996		for (pp = &parent->child; (p = *pp) != NULL; pp = &p->sibling) {
   997			if (p->end < res->start)
   998				continue;
   999			if (res->end < p->start)
  1000				break;
  1001			if (p->start < res->start || p->end > res->end)
  1002				return -1;	/* not completely contained */
  1003			if (firstpp == NULL)
  1004				firstpp = pp;
  1005		}
  1006		if (firstpp == NULL)
  1007			return -1;	/* didn't find any conflicting entries? */
  1008		res->parent = parent;
  1009		res->child = *firstpp;
  1010		res->sibling = *pp;
  1011		*firstpp = res;
  1012		*pp = NULL;
  1013		for (p = res->child; p != NULL; p = p->sibling) {
  1014			p->parent = res;
  1015			pr_debug("PCI: Reparented %s %pR under %s\n",
  1016				 p->name, p, res->name);
  1017		}
  1018		return 0;
  1019	}
  1020	EXPORT_SYMBOL(reparent_resources);
  1021	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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Re: [PATCH v5 1/4] resource: Move reparent_resources() to kernel/resource.c and make it public

[Baoquan He]

On 06/12/18 at 11:28am, Baoquan He wrote:
> reparent_resources() is duplicated in arch/microblaze/pci/pci-common.c
> and arch/powerpc/kernel/pci-common.c, so move it to kernel/resource.c
> so that it's shared. Later its code also need be updated using list_head
> to replace singly linked list.
> 
> Signed-off-by: Baoquan He <bhe-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> Cc: Michal Simek <monstr-pSz03upnqPeHXe+LvDLADg@public.gmane.org>
> Cc: Benjamin Herrenschmidt <benh-XVmvHMARGAS8U2dJNN8I7kB+6BGkLq7r@public.gmane.org>
> Cc: Paul Mackerras <paulus-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>
> Cc: Michael Ellerman <mpe-Gsx/Oe8HsFggBc27wqDAHg@public.gmane.org>
> ---
> v4->v5:
>   Fix several code bugs reported by test robot on ARCH powerpc and
>   microblaze.

Oops, I mistakenly added the patch change log of the current patch 0002
here. This patch is a newly added one.

> 
> v3->v4:
>   Fix several bugs test robot reported. And change patch log.
> 
> v2->v3:
>   Rename resource functions first_child() and sibling() to
>   resource_first_chils() and resource_sibling(). Dan suggested this.
> 
>   Move resource_first_chils() and resource_sibling() to linux/ioport.h
>   and make them as inline function. Rob suggested this. Accordingly add
>   linux/list.h including in linux/ioport.h, please help review if this
>   bring efficiency degradation or code redundancy.
> 
>   The change on struct resource {} bring two pointers of size increase,
>   mention this in git log to make it more specifically, Rob suggested
>   this.
> 
>  arch/microblaze/pci/pci-common.c | 37 -------------------------------------
>  arch/powerpc/kernel/pci-common.c | 35 -----------------------------------
>  include/linux/ioport.h           |  1 +
>  kernel/resource.c                | 36 ++++++++++++++++++++++++++++++++++++
>  4 files changed, 37 insertions(+), 72 deletions(-)
> 
> diff --git a/arch/microblaze/pci/pci-common.c b/arch/microblaze/pci/pci-common.c
> index f34346d56095..7899bafab064 100644
> --- a/arch/microblaze/pci/pci-common.c
> +++ b/arch/microblaze/pci/pci-common.c
> @@ -619,43 +619,6 @@ int pcibios_add_device(struct pci_dev *dev)
>  EXPORT_SYMBOL(pcibios_add_device);
>  
>  /*
> - * Reparent resource children of pr that conflict with res
> - * under res, and make res replace those children.
> - */
> -static int __init reparent_resources(struct resource *parent,
> -				     struct resource *res)
> -{
> -	struct resource *p, **pp;
> -	struct resource **firstpp = NULL;
> -
> -	for (pp = &parent->child; (p = *pp) != NULL; pp = &p->sibling) {
> -		if (p->end < res->start)
> -			continue;
> -		if (res->end < p->start)
> -			break;
> -		if (p->start < res->start || p->end > res->end)
> -			return -1;	/* not completely contained */
> -		if (firstpp == NULL)
> -			firstpp = pp;
> -	}
> -	if (firstpp == NULL)
> -		return -1;	/* didn't find any conflicting entries? */
> -	res->parent = parent;
> -	res->child = *firstpp;
> -	res->sibling = *pp;
> -	*firstpp = res;
> -	*pp = NULL;
> -	for (p = res->child; p != NULL; p = p->sibling) {
> -		p->parent = res;
> -		pr_debug("PCI: Reparented %s [%llx..%llx] under %s\n",
> -			 p->name,
> -			 (unsigned long long)p->start,
> -			 (unsigned long long)p->end, res->name);
> -	}
> -	return 0;
> -}
> -
> -/*
>   *  Handle resources of PCI devices.  If the world were perfect, we could
>   *  just allocate all the resource regions and do nothing more.  It isn't.
>   *  On the other hand, we cannot just re-allocate all devices, as it would
> diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
> index fe9733ffffaa..926035bb378d 100644
> --- a/arch/powerpc/kernel/pci-common.c
> +++ b/arch/powerpc/kernel/pci-common.c
> @@ -1088,41 +1088,6 @@ resource_size_t pcibios_align_resource(void *data, const struct resource *res,
>  EXPORT_SYMBOL(pcibios_align_resource);
>  
>  /*
> - * Reparent resource children of pr that conflict with res
> - * under res, and make res replace those children.
> - */
> -static int reparent_resources(struct resource *parent,
> -				     struct resource *res)
> -{
> -	struct resource *p, **pp;
> -	struct resource **firstpp = NULL;
> -
> -	for (pp = &parent->child; (p = *pp) != NULL; pp = &p->sibling) {
> -		if (p->end < res->start)
> -			continue;
> -		if (res->end < p->start)
> -			break;
> -		if (p->start < res->start || p->end > res->end)
> -			return -1;	/* not completely contained */
> -		if (firstpp == NULL)
> -			firstpp = pp;
> -	}
> -	if (firstpp == NULL)
> -		return -1;	/* didn't find any conflicting entries? */
> -	res->parent = parent;
> -	res->child = *firstpp;
> -	res->sibling = *pp;
> -	*firstpp = res;
> -	*pp = NULL;
> -	for (p = res->child; p != NULL; p = p->sibling) {
> -		p->parent = res;
> -		pr_debug("PCI: Reparented %s %pR under %s\n",
> -			 p->name, p, res->name);
> -	}
> -	return 0;
> -}
> -
> -/*
>   *  Handle resources of PCI devices.  If the world were perfect, we could
>   *  just allocate all the resource regions and do nothing more.  It isn't.
>   *  On the other hand, we cannot just re-allocate all devices, as it would
> diff --git a/include/linux/ioport.h b/include/linux/ioport.h
> index da0ebaec25f0..dfdcd0bfe54e 100644
> --- a/include/linux/ioport.h
> +++ b/include/linux/ioport.h
> @@ -192,6 +192,7 @@ extern int allocate_resource(struct resource *root, struct resource *new,
>  struct resource *lookup_resource(struct resource *root, resource_size_t start);
>  int adjust_resource(struct resource *res, resource_size_t start,
>  		    resource_size_t size);
> +int reparent_resources(struct resource *parent, struct resource *res);
>  resource_size_t resource_alignment(struct resource *res);
>  static inline resource_size_t resource_size(const struct resource *res)
>  {
> diff --git a/kernel/resource.c b/kernel/resource.c
> index 30e1bc68503b..5e7c56d5d838 100644
> --- a/kernel/resource.c
> +++ b/kernel/resource.c
> @@ -983,6 +983,42 @@ int adjust_resource(struct resource *res, resource_size_t start,
>  }
>  EXPORT_SYMBOL(adjust_resource);
>  
> +/*
> + * Reparent resource children of pr that conflict with res
> + * under res, and make res replace those children.
> + */
> +static int reparent_resources(struct resource *parent,
> +				     struct resource *res)
> +{
> +	struct resource *p, **pp;
> +	struct resource **firstpp = NULL;
> +
> +	for (pp = &parent->child; (p = *pp) != NULL; pp = &p->sibling) {
> +		if (p->end < res->start)
> +			continue;
> +		if (res->end < p->start)
> +			break;
> +		if (p->start < res->start || p->end > res->end)
> +			return -1;	/* not completely contained */
> +		if (firstpp == NULL)
> +			firstpp = pp;
> +	}
> +	if (firstpp == NULL)
> +		return -1;	/* didn't find any conflicting entries? */
> +	res->parent = parent;
> +	res->child = *firstpp;
> +	res->sibling = *pp;
> +	*firstpp = res;
> +	*pp = NULL;
> +	for (p = res->child; p != NULL; p = p->sibling) {
> +		p->parent = res;
> +		pr_debug("PCI: Reparented %s %pR under %s\n",
> +			 p->name, p, res->name);
> +	}
> +	return 0;
> +}
> +EXPORT_SYMBOL(reparent_resources);
> +
>  static void __init __reserve_region_with_split(struct resource *root,
>  		resource_size_t start, resource_size_t end,
>  		const char *name)
> -- 
> 2.13.6
> 

Re: [PATCH v5 1/4] resource: Move reparent_resources() to kernel/resource.c and make it public

[Andy Shevchenko]

On Tue, Jun 12, 2018 at 6:28 AM, Baoquan He <bhe-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> wrote:
> reparent_resources() is duplicated in arch/microblaze/pci/pci-common.c
> and arch/powerpc/kernel/pci-common.c, so move it to kernel/resource.c
> so that it's shared. Later its code also need be updated using list_head
> to replace singly linked list.

While this is a good deduplication of the code, some requirements for
public functions would be good to satisfy.

> +/*
> + * Reparent resource children of pr that conflict with res
> + * under res, and make res replace those children.
> + */

kernel doc format, though...

> +static int reparent_resources(struct resource *parent,
> +                                    struct resource *res)

...is it really public with static keyword?!



> +{

> +       for (pp = &parent->child; (p = *pp) != NULL; pp = &p->sibling) {
> +               if (p->end < res->start)
> +                       continue;
> +               if (res->end < p->start)
> +                       break;

> +               if (p->start < res->start || p->end > res->end)
> +                       return -1;      /* not completely contained */

Usually we are expecting real eeror codes.

> +               if (firstpp == NULL)
> +                       firstpp = pp;
> +       }

> +       if (firstpp == NULL)
> +               return -1;      /* didn't find any conflicting entries? */

Ditto.

> +}
> +EXPORT_SYMBOL(reparent_resources);

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v5 1/4] resource: Move reparent_resources() to kernel/resource.c and make it public

[Baoquan He]

On 06/12/18 at 11:29am, Andy Shevchenko wrote:
> On Tue, Jun 12, 2018 at 6:28 AM, Baoquan He <bhe-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> wrote:
> > reparent_resources() is duplicated in arch/microblaze/pci/pci-common.c
> > and arch/powerpc/kernel/pci-common.c, so move it to kernel/resource.c
> > so that it's shared. Later its code also need be updated using list_head
> > to replace singly linked list.
> 
> While this is a good deduplication of the code, some requirements for
> public functions would be good to satisfy.
> 
> > +/*
> > + * Reparent resource children of pr that conflict with res
> > + * under res, and make res replace those children.
> > + */
> 
> kernel doc format, though...

> 
> > +static int reparent_resources(struct resource *parent,
> > +                                    struct resource *res)
> 
> ...is it really public with static keyword?!

Thanks for looking into this. This is a code bug, I copied and changed,
but forgot merging the changing to local commit. And the error reported
by test robot in patch 2 was changed too locally, forgot merging it to
patch. Will repost to address this.

> 
> 
> 
> > +{
> 
> > +       for (pp = &parent->child; (p = *pp) != NULL; pp = &p->sibling) {
> > +               if (p->end < res->start)
> > +                       continue;
> > +               if (res->end < p->start)
> > +                       break;
> 
> > +               if (p->start < res->start || p->end > res->end)
> > +                       return -1;      /* not completely contained */
> 
> Usually we are expecting real eeror codes.

Hmm, I just copied it from arch/powerpc/kernel/pci-common.c. The
function interface expects an integer returned value, not sure what a
real error codes look like, could you give more hints? Will change
accordingly.

> 
> > +               if (firstpp == NULL)
> > +                       firstpp = pp;
> > +       }
> 
> > +       if (firstpp == NULL)
> > +               return -1;      /* didn't find any conflicting entries? */
> 
> Ditto.
> 
> > +}
> > +EXPORT_SYMBOL(reparent_resources);
> 
> -- 
> With Best Regards,
> Andy Shevchenko

Re: [PATCH v5 1/4] resource: Move reparent_resources() to kernel/resource.c and make it public

[Andy Shevchenko]

On Tue, Jun 12, 2018 at 12:38 PM, Baoquan He <bhe-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> wrote:
> On 06/12/18 at 11:29am, Andy Shevchenko wrote:
>> On Tue, Jun 12, 2018 at 6:28 AM, Baoquan He <bhe-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> wrote:

>> > +{
>>
>> > +       for (pp = &parent->child; (p = *pp) != NULL; pp = &p->sibling) {
>> > +               if (p->end < res->start)
>> > +                       continue;
>> > +               if (res->end < p->start)
>> > +                       break;
>>
>> > +               if (p->start < res->start || p->end > res->end)
>> > +                       return -1;      /* not completely contained */
>>
>> Usually we are expecting real eeror codes.
>
> Hmm, I just copied it from arch/powerpc/kernel/pci-common.c. The
> function interface expects an integer returned value, not sure what a
> real error codes look like, could you give more hints? Will change
> accordingly.

I briefly looked at the code and error codes we have, so, my proposal
is one of the following
 - use -ECANCELED (not the best choice for first occurrence here,
though I can't find better)
 - use positive integers (or enum), like
  #define RES_REPARENTED 0
  #define RES_OVERLAPPED 1
  #define RES_NOCONFLICT 2


>> > +               if (firstpp == NULL)
>> > +                       firstpp = pp;
>> > +       }
>>
>> > +       if (firstpp == NULL)
>> > +               return -1;      /* didn't find any conflicting entries? */
>>
>> Ditto.

Ditto.

>>
>> > +}
>> > +EXPORT_SYMBOL(reparent_resources);

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v5 1/4] resource: Move reparent_resources() to kernel/resource.c and make it public

[Andy Shevchenko]

On Tue, Jun 12, 2018 at 5:20 PM, Andy Shevchenko
<andy.shevchenko-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> On Tue, Jun 12, 2018 at 12:38 PM, Baoquan He <bhe-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> wrote:
>> On 06/12/18 at 11:29am, Andy Shevchenko wrote:
>>> On Tue, Jun 12, 2018 at 6:28 AM, Baoquan He <bhe-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> wrote:
>
>>> > +{
>>>
>>> > +       for (pp = &parent->child; (p = *pp) != NULL; pp = &p->sibling) {
>>> > +               if (p->end < res->start)
>>> > +                       continue;
>>> > +               if (res->end < p->start)
>>> > +                       break;
>>>
>>> > +               if (p->start < res->start || p->end > res->end)
>>> > +                       return -1;      /* not completely contained */
>>>
>>> Usually we are expecting real eeror codes.
>>
>> Hmm, I just copied it from arch/powerpc/kernel/pci-common.c. The
>> function interface expects an integer returned value, not sure what a
>> real error codes look like, could you give more hints? Will change
>> accordingly.
>
> I briefly looked at the code and error codes we have, so, my proposal
> is one of the following

>  - use -ECANCELED (not the best choice for first occurrence here,
> though I can't find better)

Actually -ENOTSUPP might suit the first case (although the actual
would be something like -EOVERLAP, which we don't have)

>  - use positive integers (or enum), like
>   #define RES_REPARENTED 0
>   #define RES_OVERLAPPED 1
>   #define RES_NOCONFLICT 2
>
>
>>> > +               if (firstpp == NULL)
>>> > +                       firstpp = pp;
>>> > +       }
>>>
>>> > +       if (firstpp == NULL)
>>> > +               return -1;      /* didn't find any conflicting entries? */
>>>
>>> Ditto.
>
> Ditto.
>
>>>
>>> > +}
>>> > +EXPORT_SYMBOL(reparent_resources);
>
> --
> With Best Regards,
> Andy Shevchenko



-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v5 1/4] resource: Move reparent_resources() to kernel/resource.c and make it public

[Baoquan He]

Hi Andy,

On 06/12/18 at 05:24pm, Andy Shevchenko wrote:
> On Tue, Jun 12, 2018 at 5:20 PM, Andy Shevchenko
> <andy.shevchenko-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> >> Hmm, I just copied it from arch/powerpc/kernel/pci-common.c. The
> >> function interface expects an integer returned value, not sure what a
> >> real error codes look like, could you give more hints? Will change
> >> accordingly.
> >
> > I briefly looked at the code and error codes we have, so, my proposal
> > is one of the following
> 
> >  - use -ECANCELED (not the best choice for first occurrence here,
> > though I can't find better)
> 
> Actually -ENOTSUPP might suit the first case (although the actual
> would be something like -EOVERLAP, which we don't have)

Sorry for late reply, and many thanks for your great suggestion.

I am fine to use -ENOTSUPP as the first returned value, and -ECANCELED
for the 2nd one. Or define an enum as you suggested inside the function
or in header file.

Or use -EBUSY for the first case because existing resource is
overlapping but not fully contained by 'res'; and -EINVAL for
the 2nd case since didn't find any one resources which is contained by
'res', means we passed in a invalid resource. 

All is fine to me, I can repost with each of them.

Thanks
Baoquan

> 
> >  - use positive integers (or enum), like
> >   #define RES_REPARENTED 0
> >   #define RES_OVERLAPPED 1
> >   #define RES_NOCONFLICT 2
> >
> >
> >>> > +               if (firstpp == NULL)
> >>> > +                       firstpp = pp;
> >>> > +       }
> >>>
> >>> > +       if (firstpp == NULL)
> >>> > +               return -1;      /* didn't find any conflicting entries? */
> >>>
> >>> Ditto.
> >
> > Ditto.
> >
> >>>
> >>> > +}
> >>> > +EXPORT_SYMBOL(reparent_resources);
> >
> > --
> > With Best Regards,
> > Andy Shevchenko
> 
> 
> 
> -- 
> With Best Regards,
> Andy Shevchenko

Re: [PATCH v5 1/4] resource: Move reparent_resources() to kernel/resource.c and make it public

[Andy Shevchenko]

On Tue, Jul 3, 2018 at 5:55 PM, Baoquan He <bhe@redhat.com> wrote:
> On 06/12/18 at 05:24pm, Andy Shevchenko wrote:
>> On Tue, Jun 12, 2018 at 5:20 PM, Andy Shevchenko
>> <andy.shevchenko@gmail.com> wrote:

>> > I briefly looked at the code and error codes we have, so, my proposal
>> > is one of the following
>>
>> >  - use -ECANCELED (not the best choice for first occurrence here,
>> > though I can't find better)
>>
>> Actually -ENOTSUPP might suit the first case (although the actual
>> would be something like -EOVERLAP, which we don't have)
>
> Sorry for late reply, and many thanks for your great suggestion.
>

> I am fine to use -ENOTSUPP as the first returned value, and -ECANCELED
> for the 2nd one.

I have no strong opinion, but I like (slightly better) this approach ^^^

> Or define an enum as you suggested inside the function
> or in header file.

>
> Or use -EBUSY for the first case because existing resource is
> overlapping but not fully contained by 'res'; and -EINVAL for
> the 2nd case since didn't find any one resources which is contained by
> 'res', means we passed in a invalid resource.
>
> All is fine to me, I can repost with each of them.

>> >  - use positive integers (or enum), like
>> >   #define RES_REPARENTED 0
>> >   #define RES_OVERLAPPED 1
>> >   #define RES_NOCONFLICT 2

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v5 1/4] resource: Move reparent_resources() to kernel/resource.c and make it public

[Baoquan He]

On 07/03/18 at 11:57pm, Andy Shevchenko wrote:
> On Tue, Jul 3, 2018 at 5:55 PM, Baoquan He <bhe-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> wrote:
> > On 06/12/18 at 05:24pm, Andy Shevchenko wrote:
> >> On Tue, Jun 12, 2018 at 5:20 PM, Andy Shevchenko
> >> <andy.shevchenko-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> 
> >> > I briefly looked at the code and error codes we have, so, my proposal
> >> > is one of the following
> >>
> >> >  - use -ECANCELED (not the best choice for first occurrence here,
> >> > though I can't find better)
> >>
> >> Actually -ENOTSUPP might suit the first case (although the actual
> >> would be something like -EOVERLAP, which we don't have)
> >
> > Sorry for late reply, and many thanks for your great suggestion.
> >
> 
> > I am fine to use -ENOTSUPP as the first returned value, and -ECANCELED
> > for the 2nd one.
> 
> I have no strong opinion, but I like (slightly better) this approach ^^^

Done, post v6 in this way, many thanks.

> 
> > Or define an enum as you suggested inside the function
> > or in header file.
> 
> >
> > Or use -EBUSY for the first case because existing resource is
> > overlapping but not fully contained by 'res'; and -EINVAL for
> > the 2nd case since didn't find any one resources which is contained by
> > 'res', means we passed in a invalid resource.
> >
> > All is fine to me, I can repost with each of them.
> 
> >> >  - use positive integers (or enum), like
> >> >   #define RES_REPARENTED 0
> >> >   #define RES_OVERLAPPED 1
> >> >   #define RES_NOCONFLICT 2
> 
> -- 
> With Best Regards,
> Andy Shevchenko

Re: [PATCH v5 1/4] resource: Move reparent_resources() to kernel/resource.c and make it public

[Baoquan He]

On 06/12/18 at 11:29am, Andy Shevchenko wrote:
> On Tue, Jun 12, 2018 at 6:28 AM, Baoquan He <bhe-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> wrote:
> > reparent_resources() is duplicated in arch/microblaze/pci/pci-common.c
> > and arch/powerpc/kernel/pci-common.c, so move it to kernel/resource.c
> > so that it's shared. Later its code also need be updated using list_head
> > to replace singly linked list.
> 
> While this is a good deduplication of the code, some requirements for
> public functions would be good to satisfy.
> 
> > +/*
> > + * Reparent resource children of pr that conflict with res
> > + * under res, and make res replace those children.
> > + */
> 
> kernel doc format, though...

Will rewrite it, thanks.

> 
> > +static int reparent_resources(struct resource *parent,
> > +                                    struct resource *res)
> 
> ...is it really public with static keyword?!
> 
> 
> 
> > +{
> 
> > +       for (pp = &parent->child; (p = *pp) != NULL; pp = &p->sibling) {
> > +               if (p->end < res->start)
> > +                       continue;
> > +               if (res->end < p->start)
> > +                       break;
> 
> > +               if (p->start < res->start || p->end > res->end)
> > +                       return -1;      /* not completely contained */
> 
> Usually we are expecting real eeror codes.
> 
> > +               if (firstpp == NULL)
> > +                       firstpp = pp;
> > +       }
> 
> > +       if (firstpp == NULL)
> > +               return -1;      /* didn't find any conflicting entries? */
> 
> Ditto.
> 
> > +}
> > +EXPORT_SYMBOL(reparent_resources);
> 
> -- 
> With Best Regards,
> Andy Shevchenko

[PATCH v5 2/4] resource: Use list_head to link sibling resource

[Baoquan He]

The struct resource uses singly linked list to link siblings, implemented
by pointer operation. Replace it with list_head for better code readability.

Based on this list_head replacement, it will be very easy to do reverse
iteration on iomem_resource's sibling list in later patch.

Besides, type of member variables of struct resource, sibling and child, are
changed from 'struct resource *' to 'struct list_head'. This brings two
pointers of size increase.

Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Cc: David Airlie <airlied@linux.ie>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Frank Rowand <frowand.list@gmail.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Jonathan Derrick <jonathan.derrick@intel.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Yaowei Bai <baiyaowei@cmss.chinamobile.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: devel@linuxdriverproject.org
Cc: linux-input@vger.kernel.org
Cc: linux-nvdimm@lists.01.org
Cc: devicetree@vger.kernel.org
Cc: linux-pci@vger.kernel.org
---
 arch/arm/plat-samsung/pm-check.c            |   6 +-
 arch/microblaze/pci/pci-common.c            |   4 +-
 arch/powerpc/kernel/pci-common.c            |   4 +-
 arch/sparc/kernel/ioport.c                  |   2 +-
 arch/xtensa/include/asm/pci-bridge.h        |   4 +-
 drivers/eisa/eisa-bus.c                     |   2 +
 drivers/gpu/drm/drm_memory.c                |   3 +-
 drivers/gpu/drm/gma500/gtt.c                |   5 +-
 drivers/hv/vmbus_drv.c                      |  52 +++----
 drivers/input/joystick/iforce/iforce-main.c |   4 +-
 drivers/nvdimm/namespace_devs.c             |   6 +-
 drivers/nvdimm/nd.h                         |   5 +-
 drivers/of/address.c                        |   4 +-
 drivers/parisc/lba_pci.c                    |   4 +-
 drivers/pci/host/vmd.c                      |   8 +-
 drivers/pci/probe.c                         |   2 +
 drivers/pci/setup-bus.c                     |   2 +-
 include/linux/ioport.h                      |  17 ++-
 kernel/resource.c                           | 211 ++++++++++++++--------------
 19 files changed, 176 insertions(+), 169 deletions(-)

diff --git a/arch/arm/plat-samsung/pm-check.c b/arch/arm/plat-samsung/pm-check.c
index cd2c02c68bc3..5494355b1c49 100644
--- a/arch/arm/plat-samsung/pm-check.c
+++ b/arch/arm/plat-samsung/pm-check.c
@@ -46,8 +46,8 @@ typedef u32 *(run_fn_t)(struct resource *ptr, u32 *arg);
 static void s3c_pm_run_res(struct resource *ptr, run_fn_t fn, u32 *arg)
 {
 	while (ptr != NULL) {
-		if (ptr->child != NULL)
-			s3c_pm_run_res(ptr->child, fn, arg);
+		if (!list_empty(&ptr->child))
+			s3c_pm_run_res(resource_first_child(&ptr->child), fn, arg);
 
 		if ((ptr->flags & IORESOURCE_SYSTEM_RAM)
 				== IORESOURCE_SYSTEM_RAM) {
@@ -57,7 +57,7 @@ static void s3c_pm_run_res(struct resource *ptr, run_fn_t fn, u32 *arg)
 			arg = (fn)(ptr, arg);
 		}
 
-		ptr = ptr->sibling;
+		ptr = resource_sibling(ptr);
 	}
 }
 
diff --git a/arch/microblaze/pci/pci-common.c b/arch/microblaze/pci/pci-common.c
index 7899bafab064..2bf73e27e231 100644
--- a/arch/microblaze/pci/pci-common.c
+++ b/arch/microblaze/pci/pci-common.c
@@ -533,7 +533,9 @@ void pci_process_bridge_OF_ranges(struct pci_controller *hose,
 			res->flags = range.flags;
 			res->start = range.cpu_addr;
 			res->end = range.cpu_addr + range.size - 1;
-			res->parent = res->child = res->sibling = NULL;
+			res->parent = NULL;
+			INIT_LIST_HEAD(&res->child);
+			INIT_LIST_HEAD(&res->sibling);
 		}
 	}
 
diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
index 926035bb378d..28fbe83c9daf 100644
--- a/arch/powerpc/kernel/pci-common.c
+++ b/arch/powerpc/kernel/pci-common.c
@@ -761,7 +761,9 @@ void pci_process_bridge_OF_ranges(struct pci_controller *hose,
 			res->flags = range.flags;
 			res->start = range.cpu_addr;
 			res->end = range.cpu_addr + range.size - 1;
-			res->parent = res->child = res->sibling = NULL;
+			res->parent = NULL;
+			INIT_LIST_HEAD(&res->child);
+			INIT_LIST_HEAD(&res->sibling);
 		}
 	}
 }
diff --git a/arch/sparc/kernel/ioport.c b/arch/sparc/kernel/ioport.c
index cca9134cfa7d..99efe4e98b16 100644
--- a/arch/sparc/kernel/ioport.c
+++ b/arch/sparc/kernel/ioport.c
@@ -669,7 +669,7 @@ static int sparc_io_proc_show(struct seq_file *m, void *v)
 	struct resource *root = m->private, *r;
 	const char *nm;
 
-	for (r = root->child; r != NULL; r = r->sibling) {
+	list_for_each_entry(r, &root->child, sibling) {
 		if ((nm = r->name) == NULL) nm = "???";
 		seq_printf(m, "%016llx-%016llx: %s\n",
 				(unsigned long long)r->start,
diff --git a/arch/xtensa/include/asm/pci-bridge.h b/arch/xtensa/include/asm/pci-bridge.h
index 0b68c76ec1e6..f487b06817df 100644
--- a/arch/xtensa/include/asm/pci-bridge.h
+++ b/arch/xtensa/include/asm/pci-bridge.h
@@ -71,8 +71,8 @@ static inline void pcibios_init_resource(struct resource *res,
 	res->flags = flags;
 	res->name = name;
 	res->parent = NULL;
-	res->sibling = NULL;
-	res->child = NULL;
+	INIT_LIST_HEAD(&res->child);
+	INIT_LIST_HEAD(&res->sibling);
 }
 
 
diff --git a/drivers/eisa/eisa-bus.c b/drivers/eisa/eisa-bus.c
index 1e8062f6dbfc..dba78f75fd06 100644
--- a/drivers/eisa/eisa-bus.c
+++ b/drivers/eisa/eisa-bus.c
@@ -408,6 +408,8 @@ static struct resource eisa_root_res = {
 	.start = 0,
 	.end   = 0xffffffff,
 	.flags = IORESOURCE_IO,
+	.sibling = LIST_HEAD_INIT(eisa_root_res.sibling),
+	.child  = LIST_HEAD_INIT(eisa_root_res.child),
 };
 
 static int eisa_bus_count;
diff --git a/drivers/gpu/drm/drm_memory.c b/drivers/gpu/drm/drm_memory.c
index 3c54044214db..53e300a993dc 100644
--- a/drivers/gpu/drm/drm_memory.c
+++ b/drivers/gpu/drm/drm_memory.c
@@ -155,9 +155,8 @@ u64 drm_get_max_iomem(void)
 	struct resource *tmp;
 	resource_size_t max_iomem = 0;
 
-	for (tmp = iomem_resource.child; tmp; tmp = tmp->sibling) {
+	list_for_each_entry(tmp, &iomem_resource.child, sibling)
 		max_iomem = max(max_iomem,  tmp->end);
-	}
 
 	return max_iomem;
 }
diff --git a/drivers/gpu/drm/gma500/gtt.c b/drivers/gpu/drm/gma500/gtt.c
index 3949b0990916..addd3bc009af 100644
--- a/drivers/gpu/drm/gma500/gtt.c
+++ b/drivers/gpu/drm/gma500/gtt.c
@@ -565,7 +565,7 @@ int psb_gtt_init(struct drm_device *dev, int resume)
 int psb_gtt_restore(struct drm_device *dev)
 {
 	struct drm_psb_private *dev_priv = dev->dev_private;
-	struct resource *r = dev_priv->gtt_mem->child;
+	struct resource *r;
 	struct gtt_range *range;
 	unsigned int restored = 0, total = 0, size = 0;
 
@@ -573,14 +573,13 @@ int psb_gtt_restore(struct drm_device *dev)
 	mutex_lock(&dev_priv->gtt_mutex);
 	psb_gtt_init(dev, 1);
 
-	while (r != NULL) {
+	list_for_each_entry(r, &dev_priv->gtt_mem->child, sibling) {
 		range = container_of(r, struct gtt_range, resource);
 		if (range->pages) {
 			psb_gtt_insert(dev, range, 1);
 			size += range->resource.end - range->resource.start;
 			restored++;
 		}
-		r = r->sibling;
 		total++;
 	}
 	mutex_unlock(&dev_priv->gtt_mutex);
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index b10fe26c4891..d87ec5a1bc4c 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -1412,9 +1412,8 @@ static acpi_status vmbus_walk_resources(struct acpi_resource *res, void *ctx)
 {
 	resource_size_t start = 0;
 	resource_size_t end = 0;
-	struct resource *new_res;
+	struct resource *new_res, *tmp;
 	struct resource **old_res = &hyperv_mmio;
-	struct resource **prev_res = NULL;
 
 	switch (res->type) {
 
@@ -1461,44 +1460,36 @@ static acpi_status vmbus_walk_resources(struct acpi_resource *res, void *ctx)
 	/*
 	 * If two ranges are adjacent, merge them.
 	 */
-	do {
-		if (!*old_res) {
-			*old_res = new_res;
-			break;
-		}
-
-		if (((*old_res)->end + 1) == new_res->start) {
-			(*old_res)->end = new_res->end;
+	if (!*old_res) {
+		*old_res = new_res;
+		return AE_OK;
+	}
+	tmp = *old_res;
+	list_for_each_entry_from(tmp, &tmp->parent->child, sibling) {
+		if ((tmp->end + 1) == new_res->start) {
+			tmp->end = new_res->end;
 			kfree(new_res);
 			break;
 		}
 
-		if ((*old_res)->start == new_res->end + 1) {
-			(*old_res)->start = new_res->start;
+		if (tmp->start == new_res->end + 1) {
+			tmp->start = new_res->start;
 			kfree(new_res);
 			break;
 		}
 
-		if ((*old_res)->start > new_res->end) {
-			new_res->sibling = *old_res;
-			if (prev_res)
-				(*prev_res)->sibling = new_res;
-			*old_res = new_res;
+		if (tmp->start > new_res->end) {
+			list_add(&new_res->sibling, tmp->sibling.prev);
 			break;
 		}
-
-		prev_res = old_res;
-		old_res = &(*old_res)->sibling;
-
-	} while (1);
+	}
 
 	return AE_OK;
 }
 
 static int vmbus_acpi_remove(struct acpi_device *device)
 {
-	struct resource *cur_res;
-	struct resource *next_res;
+	struct resource *res;
 
 	if (hyperv_mmio) {
 		if (fb_mmio) {
@@ -1507,10 +1498,9 @@ static int vmbus_acpi_remove(struct acpi_device *device)
 			fb_mmio = NULL;
 		}
 
-		for (cur_res = hyperv_mmio; cur_res; cur_res = next_res) {
-			next_res = cur_res->sibling;
-			kfree(cur_res);
-		}
+		res = hyperv_mmio;
+		list_for_each_entry_from(res, &res->parent->child, sibling)
+			kfree(res);
 	}
 
 	return 0;
@@ -1596,7 +1586,8 @@ int vmbus_allocate_mmio(struct resource **new, struct hv_device *device_obj,
 		}
 	}
 
-	for (iter = hyperv_mmio; iter; iter = iter->sibling) {
+	iter = hyperv_mmio;
+	list_for_each_entry_from(iter, &iter->parent->child, sibling) {
 		if ((iter->start >= max) || (iter->end <= min))
 			continue;
 
@@ -1639,7 +1630,8 @@ void vmbus_free_mmio(resource_size_t start, resource_size_t size)
 	struct resource *iter;
 
 	down(&hyperv_mmio_lock);
-	for (iter = hyperv_mmio; iter; iter = iter->sibling) {
+	iter = hyperv_mmio;
+	list_for_each_entry_from(iter, &iter->parent->child, sibling) {
 		if ((iter->start >= start + size) || (iter->end <= start))
 			continue;
 
diff --git a/drivers/input/joystick/iforce/iforce-main.c b/drivers/input/joystick/iforce/iforce-main.c
index daeeb4c7e3b0..5c0be27b33ff 100644
--- a/drivers/input/joystick/iforce/iforce-main.c
+++ b/drivers/input/joystick/iforce/iforce-main.c
@@ -305,8 +305,8 @@ int iforce_init_device(struct iforce *iforce)
 	iforce->device_memory.end = 200;
 	iforce->device_memory.flags = IORESOURCE_MEM;
 	iforce->device_memory.parent = NULL;
-	iforce->device_memory.child = NULL;
-	iforce->device_memory.sibling = NULL;
+	INIT_LIST_HEAD(&iforce->device_memory.child);
+	INIT_LIST_HEAD(&iforce->device_memory.sibling);
 
 /*
  * Wait until device ready - until it sends its first response.
diff --git a/drivers/nvdimm/namespace_devs.c b/drivers/nvdimm/namespace_devs.c
index 28afdd668905..f53d410d9981 100644
--- a/drivers/nvdimm/namespace_devs.c
+++ b/drivers/nvdimm/namespace_devs.c
@@ -637,7 +637,7 @@ static resource_size_t scan_allocate(struct nd_region *nd_region,
  retry:
 	first = 0;
 	for_each_dpa_resource(ndd, res) {
-		struct resource *next = res->sibling, *new_res = NULL;
+		struct resource *next = resource_sibling(res), *new_res = NULL;
 		resource_size_t allocate, available = 0;
 		enum alloc_loc loc = ALLOC_ERR;
 		const char *action;
@@ -763,7 +763,7 @@ static resource_size_t scan_allocate(struct nd_region *nd_region,
 	 * an initial "pmem-reserve pass".  Only do an initial BLK allocation
 	 * when none of the DPA space is reserved.
 	 */
-	if ((is_pmem || !ndd->dpa.child) && n == to_allocate)
+	if ((is_pmem || list_empty(&ndd->dpa.child)) && n == to_allocate)
 		return init_dpa_allocation(label_id, nd_region, nd_mapping, n);
 	return n;
 }
@@ -779,7 +779,7 @@ static int merge_dpa(struct nd_region *nd_region,
  retry:
 	for_each_dpa_resource(ndd, res) {
 		int rc;
-		struct resource *next = res->sibling;
+		struct resource *next = resource_sibling(res);
 		resource_size_t end = res->start + resource_size(res);
 
 		if (!next || strcmp(res->name, label_id->id) != 0
diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h
index 32e0364b48b9..da7da15e03e7 100644
--- a/drivers/nvdimm/nd.h
+++ b/drivers/nvdimm/nd.h
@@ -102,11 +102,10 @@ unsigned sizeof_namespace_label(struct nvdimm_drvdata *ndd);
 		(unsigned long long) (res ? res->start : 0), ##arg)
 
 #define for_each_dpa_resource(ndd, res) \
-	for (res = (ndd)->dpa.child; res; res = res->sibling)
+	list_for_each_entry(res, &(ndd)->dpa.child, sibling)
 
 #define for_each_dpa_resource_safe(ndd, res, next) \
-	for (res = (ndd)->dpa.child, next = res ? res->sibling : NULL; \
-			res; res = next, next = next ? next->sibling : NULL)
+	list_for_each_entry_safe(res, next, &(ndd)->dpa.child, sibling)
 
 struct nd_percpu_lane {
 	int count;
diff --git a/drivers/of/address.c b/drivers/of/address.c
index 53349912ac75..e2e25719ab52 100644
--- a/drivers/of/address.c
+++ b/drivers/of/address.c
@@ -330,7 +330,9 @@ int of_pci_range_to_resource(struct of_pci_range *range,
 {
 	int err;
 	res->flags = range->flags;
-	res->parent = res->child = res->sibling = NULL;
+	res->parent = NULL;
+	INIT_LIST_HEAD(&res->child);
+	INIT_LIST_HEAD(&res->sibling);
 	res->name = np->full_name;
 
 	if (res->flags & IORESOURCE_IO) {
diff --git a/drivers/parisc/lba_pci.c b/drivers/parisc/lba_pci.c
index 69bd98421eb1..7482bdfd1959 100644
--- a/drivers/parisc/lba_pci.c
+++ b/drivers/parisc/lba_pci.c
@@ -170,8 +170,8 @@ lba_dump_res(struct resource *r, int d)
 	for (i = d; i ; --i) printk(" ");
 	printk(KERN_DEBUG "%p [%lx,%lx]/%lx\n", r,
 		(long)r->start, (long)r->end, r->flags);
-	lba_dump_res(r->child, d+2);
-	lba_dump_res(r->sibling, d);
+	lba_dump_res(resource_first_child(&r->child), d+2);
+	lba_dump_res(resource_sibling(r), d);
 }
 
 
diff --git a/drivers/pci/host/vmd.c b/drivers/pci/host/vmd.c
index 942b64fc7f1f..e3ace20345c7 100644
--- a/drivers/pci/host/vmd.c
+++ b/drivers/pci/host/vmd.c
@@ -542,14 +542,14 @@ static struct pci_ops vmd_ops = {
 
 static void vmd_attach_resources(struct vmd_dev *vmd)
 {
-	vmd->dev->resource[VMD_MEMBAR1].child = &vmd->resources[1];
-	vmd->dev->resource[VMD_MEMBAR2].child = &vmd->resources[2];
+	list_add(&vmd->resources[1].sibling, &vmd->dev->resource[VMD_MEMBAR1].child);
+	list_add(&vmd->resources[2].sibling, &vmd->dev->resource[VMD_MEMBAR2].child);
 }
 
 static void vmd_detach_resources(struct vmd_dev *vmd)
 {
-	vmd->dev->resource[VMD_MEMBAR1].child = NULL;
-	vmd->dev->resource[VMD_MEMBAR2].child = NULL;
+	INIT_LIST_HEAD(&vmd->dev->resource[VMD_MEMBAR1].child);
+	INIT_LIST_HEAD(&vmd->dev->resource[VMD_MEMBAR2].child);
 }
 
 /*
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index ac876e32de4b..9624dd1dfd49 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -59,6 +59,8 @@ static struct resource *get_pci_domain_busn_res(int domain_nr)
 	r->res.start = 0;
 	r->res.end = 0xff;
 	r->res.flags = IORESOURCE_BUS | IORESOURCE_PCI_FIXED;
+	INIT_LIST_HEAD(&r->res.child);
+	INIT_LIST_HEAD(&r->res.sibling);
 
 	list_add_tail(&r->list, &pci_domain_busn_res_list);
 
diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index 79b1824e83b4..8e685af8938d 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -2107,7 +2107,7 @@ int pci_reassign_bridge_resources(struct pci_dev *bridge, unsigned long type)
 				continue;
 
 			/* Ignore BARs which are still in use */
-			if (res->child)
+			if (!list_empty(&res->child))
 				continue;
 
 			ret = add_to_list(&saved, bridge, res, 0, 0);
diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index dfdcd0bfe54e..b7456ae889dd 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -12,6 +12,7 @@
 #ifndef __ASSEMBLY__
 #include <linux/compiler.h>
 #include <linux/types.h>
+#include <linux/list.h>
 /*
  * Resources are tree-like, allowing
  * nesting etc..
@@ -22,7 +23,8 @@ struct resource {
 	const char *name;
 	unsigned long flags;
 	unsigned long desc;
-	struct resource *parent, *sibling, *child;
+	struct list_head child, sibling;
+	struct resource *parent;
 };
 
 /*
@@ -216,7 +218,6 @@ static inline bool resource_contains(struct resource *r1, struct resource *r2)
 	return r1->start <= r2->start && r1->end >= r2->end;
 }
 
-
 /* Convenience shorthand with allocation */
 #define request_region(start,n,name)		__request_region(&ioport_resource, (start), (n), (name), 0)
 #define request_muxed_region(start,n,name)	__request_region(&ioport_resource, (start), (n), (name), IORESOURCE_MUXED)
@@ -287,6 +288,18 @@ static inline bool resource_overlaps(struct resource *r1, struct resource *r2)
        return (r1->start <= r2->end && r1->end >= r2->start);
 }
 
+static inline struct resource *resource_sibling(struct resource *res)
+{
+	if (res->parent && !list_is_last(&res->sibling, &res->parent->child))
+		return list_next_entry(res, sibling);
+	return NULL;
+}
+
+static inline struct resource *resource_first_child(struct list_head *head)
+{
+	return list_first_entry_or_null(head, struct resource, sibling);
+}
+
 
 #endif /* __ASSEMBLY__ */
 #endif	/* _LINUX_IOPORT_H */
diff --git a/kernel/resource.c b/kernel/resource.c
index 5e7c56d5d838..ef9a20b75234 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -31,6 +31,8 @@ struct resource ioport_resource = {
 	.start	= 0,
 	.end	= IO_SPACE_LIMIT,
 	.flags	= IORESOURCE_IO,
+	.sibling = LIST_HEAD_INIT(ioport_resource.sibling),
+	.child  = LIST_HEAD_INIT(ioport_resource.child),
 };
 EXPORT_SYMBOL(ioport_resource);
 
@@ -39,6 +41,8 @@ struct resource iomem_resource = {
 	.start	= 0,
 	.end	= -1,
 	.flags	= IORESOURCE_MEM,
+	.sibling = LIST_HEAD_INIT(iomem_resource.sibling),
+	.child  = LIST_HEAD_INIT(iomem_resource.child),
 };
 EXPORT_SYMBOL(iomem_resource);
 
@@ -57,20 +61,20 @@ static DEFINE_RWLOCK(resource_lock);
  * by boot mem after the system is up. So for reusing the resource entry
  * we need to remember the resource.
  */
-static struct resource *bootmem_resource_free;
+static struct list_head bootmem_resource_free = LIST_HEAD_INIT(bootmem_resource_free);
 static DEFINE_SPINLOCK(bootmem_resource_lock);
 
 static struct resource *next_resource(struct resource *p, bool sibling_only)
 {
 	/* Caller wants to traverse through siblings only */
 	if (sibling_only)
-		return p->sibling;
+		return resource_sibling(p);
 
-	if (p->child)
-		return p->child;
-	while (!p->sibling && p->parent)
+	if (!list_empty(&p->child))
+		return resource_first_child(&p->child);
+	while (!resource_sibling(p) && p->parent)
 		p = p->parent;
-	return p->sibling;
+	return resource_sibling(p);
 }
 
 static void *r_next(struct seq_file *m, void *v, loff_t *pos)
@@ -90,7 +94,7 @@ static void *r_start(struct seq_file *m, loff_t *pos)
 	struct resource *p = PDE_DATA(file_inode(m->file));
 	loff_t l = 0;
 	read_lock(&resource_lock);
-	for (p = p->child; p && l < *pos; p = r_next(m, p, &l))
+	for (p = resource_first_child(&p->child); p && l < *pos; p = r_next(m, p, &l))
 		;
 	return p;
 }
@@ -153,8 +157,7 @@ static void free_resource(struct resource *res)
 
 	if (!PageSlab(virt_to_head_page(res))) {
 		spin_lock(&bootmem_resource_lock);
-		res->sibling = bootmem_resource_free;
-		bootmem_resource_free = res;
+		list_add(&res->sibling, &bootmem_resource_free);
 		spin_unlock(&bootmem_resource_lock);
 	} else {
 		kfree(res);
@@ -166,10 +169,9 @@ static struct resource *alloc_resource(gfp_t flags)
 	struct resource *res = NULL;
 
 	spin_lock(&bootmem_resource_lock);
-	if (bootmem_resource_free) {
-		res = bootmem_resource_free;
-		bootmem_resource_free = res->sibling;
-	}
+	res = resource_first_child(&bootmem_resource_free);
+	if (res)
+		list_del(&res->sibling);
 	spin_unlock(&bootmem_resource_lock);
 
 	if (res)
@@ -177,6 +179,8 @@ static struct resource *alloc_resource(gfp_t flags)
 	else
 		res = kzalloc(sizeof(struct resource), flags);
 
+	INIT_LIST_HEAD(&res->child);
+	INIT_LIST_HEAD(&res->sibling);
 	return res;
 }
 
@@ -185,7 +189,7 @@ static struct resource * __request_resource(struct resource *root, struct resour
 {
 	resource_size_t start = new->start;
 	resource_size_t end = new->end;
-	struct resource *tmp, **p;
+	struct resource *tmp;
 
 	if (end < start)
 		return root;
@@ -193,64 +197,62 @@ static struct resource * __request_resource(struct resource *root, struct resour
 		return root;
 	if (end > root->end)
 		return root;
-	p = &root->child;
-	for (;;) {
-		tmp = *p;
-		if (!tmp || tmp->start > end) {
-			new->sibling = tmp;
-			*p = new;
+
+	if (list_empty(&root->child)) {
+		list_add(&new->sibling, &root->child);
+		new->parent = root;
+		INIT_LIST_HEAD(&new->child);
+		return NULL;
+	}
+
+	list_for_each_entry(tmp, &root->child, sibling) {
+		if (tmp->start > end) {
+			list_add(&new->sibling, tmp->sibling.prev);
 			new->parent = root;
+			INIT_LIST_HEAD(&new->child);
 			return NULL;
 		}
-		p = &tmp->sibling;
 		if (tmp->end < start)
 			continue;
 		return tmp;
 	}
+
+	list_add_tail(&new->sibling, &root->child);
+	new->parent = root;
+	INIT_LIST_HEAD(&new->child);
+	return NULL;
 }
 
 static int __release_resource(struct resource *old, bool release_child)
 {
-	struct resource *tmp, **p, *chd;
+	struct resource *tmp, *next, *chd;
 
-	p = &old->parent->child;
-	for (;;) {
-		tmp = *p;
-		if (!tmp)
-			break;
+	list_for_each_entry_safe(tmp, next, &old->parent->child, sibling) {
 		if (tmp == old) {
-			if (release_child || !(tmp->child)) {
-				*p = tmp->sibling;
+			if (release_child || list_empty(&tmp->child)) {
+				list_del(&tmp->sibling);
 			} else {
-				for (chd = tmp->child;; chd = chd->sibling) {
+				list_for_each_entry(chd, &tmp->child, sibling)
 					chd->parent = tmp->parent;
-					if (!(chd->sibling))
-						break;
-				}
-				*p = tmp->child;
-				chd->sibling = tmp->sibling;
+				list_splice(&tmp->child, tmp->sibling.prev);
+				list_del(&tmp->sibling);
 			}
+
 			old->parent = NULL;
 			return 0;
 		}
-		p = &tmp->sibling;
 	}
 	return -EINVAL;
 }
 
 static void __release_child_resources(struct resource *r)
 {
-	struct resource *tmp, *p;
+	struct resource *tmp, *next;
 	resource_size_t size;
 
-	p = r->child;
-	r->child = NULL;
-	while (p) {
-		tmp = p;
-		p = p->sibling;
-
+	list_for_each_entry_safe(tmp, next, &r->child, sibling) {
 		tmp->parent = NULL;
-		tmp->sibling = NULL;
+		INIT_LIST_HEAD(&tmp->sibling);
 		__release_child_resources(tmp);
 
 		printk(KERN_DEBUG "release child resource %pR\n", tmp);
@@ -259,6 +261,8 @@ static void __release_child_resources(struct resource *r)
 		tmp->start = 0;
 		tmp->end = size - 1;
 	}
+
+	INIT_LIST_HEAD(&tmp->child);
 }
 
 void release_child_resources(struct resource *r)
@@ -343,7 +347,8 @@ static int find_next_iomem_res(struct resource *res, unsigned long desc,
 
 	read_lock(&resource_lock);
 
-	for (p = iomem_resource.child; p; p = next_resource(p, sibling_only)) {
+	for (p = resource_first_child(&iomem_resource.child); p;
+			p = next_resource(p, sibling_only)) {
 		if ((p->flags & res->flags) != res->flags)
 			continue;
 		if ((desc != IORES_DESC_NONE) && (desc != p->desc))
@@ -532,7 +537,7 @@ int region_intersects(resource_size_t start, size_t size, unsigned long flags,
 	struct resource *p;
 
 	read_lock(&resource_lock);
-	for (p = iomem_resource.child; p ; p = p->sibling) {
+	list_for_each_entry(p, &iomem_resource.child, sibling) {
 		bool is_type = (((p->flags & flags) == flags) &&
 				((desc == IORES_DESC_NONE) ||
 				 (desc == p->desc)));
@@ -586,7 +591,7 @@ static int __find_resource(struct resource *root, struct resource *old,
 			 resource_size_t  size,
 			 struct resource_constraint *constraint)
 {
-	struct resource *this = root->child;
+	struct resource *this = resource_first_child(&root->child);
 	struct resource tmp = *new, avail, alloc;
 
 	tmp.start = root->start;
@@ -596,7 +601,7 @@ static int __find_resource(struct resource *root, struct resource *old,
 	 */
 	if (this && this->start == root->start) {
 		tmp.start = (this == old) ? old->start : this->end + 1;
-		this = this->sibling;
+		this = resource_sibling(this);
 	}
 	for(;;) {
 		if (this)
@@ -632,7 +637,7 @@ next:		if (!this || this->end == root->end)
 
 		if (this != old)
 			tmp.start = this->end + 1;
-		this = this->sibling;
+		this = resource_sibling(this);
 	}
 	return -EBUSY;
 }
@@ -676,7 +681,7 @@ static int reallocate_resource(struct resource *root, struct resource *old,
 		goto out;
 	}
 
-	if (old->child) {
+	if (!list_empty(&old->child)) {
 		err = -EBUSY;
 		goto out;
 	}
@@ -757,7 +762,7 @@ struct resource *lookup_resource(struct resource *root, resource_size_t start)
 	struct resource *res;
 
 	read_lock(&resource_lock);
-	for (res = root->child; res; res = res->sibling) {
+	list_for_each_entry(res, &root->child, sibling) {
 		if (res->start == start)
 			break;
 	}
@@ -790,32 +795,27 @@ static struct resource * __insert_resource(struct resource *parent, struct resou
 			break;
 	}
 
-	for (next = first; ; next = next->sibling) {
+	for (next = first; ; next = resource_sibling(next)) {
 		/* Partial overlap? Bad, and unfixable */
 		if (next->start < new->start || next->end > new->end)
 			return next;
-		if (!next->sibling)
+		if (!resource_sibling(next))
 			break;
-		if (next->sibling->start > new->end)
+		if (resource_sibling(next)->start > new->end)
 			break;
 	}
-
 	new->parent = parent;
-	new->sibling = next->sibling;
-	new->child = first;
+	list_add(&new->sibling, &next->sibling);
+	INIT_LIST_HEAD(&new->child);
 
-	next->sibling = NULL;
-	for (next = first; next; next = next->sibling)
+	/*
+	 * From first to next, they all fall into new's region, so change them
+	 * as new's children.
+	 */
+	list_cut_position(&new->child, first->sibling.prev, &next->sibling);
+	list_for_each_entry(next, &new->child, sibling)
 		next->parent = new;
 
-	if (parent->child == first) {
-		parent->child = new;
-	} else {
-		next = parent->child;
-		while (next->sibling != first)
-			next = next->sibling;
-		next->sibling = new;
-	}
 	return NULL;
 }
 
@@ -937,19 +937,17 @@ static int __adjust_resource(struct resource *res, resource_size_t start,
 	if ((start < parent->start) || (end > parent->end))
 		goto out;
 
-	if (res->sibling && (res->sibling->start <= end))
+	if (resource_sibling(res) && (resource_sibling(res)->start <= end))
 		goto out;
 
-	tmp = parent->child;
-	if (tmp != res) {
-		while (tmp->sibling != res)
-			tmp = tmp->sibling;
+	if (res->sibling.prev != &parent->child) {
+		tmp = list_prev_entry(res, sibling);
 		if (start <= tmp->end)
 			goto out;
 	}
 
 skip:
-	for (tmp = res->child; tmp; tmp = tmp->sibling)
+	list_for_each_entry(tmp, &res->child, sibling)
 		if ((tmp->start < start) || (tmp->end > end))
 			goto out;
 
@@ -987,31 +985,33 @@ EXPORT_SYMBOL(adjust_resource);
  * Reparent resource children of pr that conflict with res
  * under res, and make res replace those children.
  */
-static int reparent_resources(struct resource *parent,
-				     struct resource *res)
+int reparent_resources(struct resource *parent, struct resource *res)
 {
-	struct resource *p, **pp;
-	struct resource **firstpp = NULL;
+	struct resource *p, *first = NULL;
 
-	for (pp = &parent->child; (p = *pp) != NULL; pp = &p->sibling) {
+	list_for_each_entry(p, &parent->child, sibling) {
 		if (p->end < res->start)
 			continue;
 		if (res->end < p->start)
 			break;
 		if (p->start < res->start || p->end > res->end)
 			return -1;	/* not completely contained */
-		if (firstpp == NULL)
-			firstpp = pp;
+		if (first == NULL)
+			first = p;
 	}
-	if (firstpp == NULL)
+	if (first == NULL)
 		return -1;	/* didn't find any conflicting entries? */
 	res->parent = parent;
-	res->child = *firstpp;
-	res->sibling = *pp;
-	*firstpp = res;
-	*pp = NULL;
-	for (p = res->child; p != NULL; p = p->sibling) {
-		p->parent = res;
+	list_add(&res->sibling, &p->sibling.prev);
+	INIT_LIST_HEAD(&res->child);
+
+	/*
+	 * From first to p's previous sibling, they all fall into
+	 * res's region, change them as res's children.
+	 */
+	list_cut_position(&res->child, first->sibling.prev, res->sibling.prev);
+	list_for_each_entry(p, &new->child, sibling) {
+                p->parent = new;
 		pr_debug("PCI: Reparented %s %pR under %s\n",
 			 p->name, p, res->name);
 	}
@@ -1210,34 +1210,32 @@ EXPORT_SYMBOL(__request_region);
 void __release_region(struct resource *parent, resource_size_t start,
 			resource_size_t n)
 {
-	struct resource **p;
+	struct resource *res;
 	resource_size_t end;
 
-	p = &parent->child;
+	res = resource_first_child(&parent->child);
 	end = start + n - 1;
 
 	write_lock(&resource_lock);
 
 	for (;;) {
-		struct resource *res = *p;
-
 		if (!res)
 			break;
 		if (res->start <= start && res->end >= end) {
 			if (!(res->flags & IORESOURCE_BUSY)) {
-				p = &res->child;
+				res = resource_first_child(&res->child);
 				continue;
 			}
 			if (res->start != start || res->end != end)
 				break;
-			*p = res->sibling;
+			list_del(&res->sibling);
 			write_unlock(&resource_lock);
 			if (res->flags & IORESOURCE_MUXED)
 				wake_up(&muxed_resource_wait);
 			free_resource(res);
 			return;
 		}
-		p = &res->sibling;
+		res = resource_sibling(res);
 	}
 
 	write_unlock(&resource_lock);
@@ -1272,9 +1270,7 @@ EXPORT_SYMBOL(__release_region);
 int release_mem_region_adjustable(struct resource *parent,
 			resource_size_t start, resource_size_t size)
 {
-	struct resource **p;
-	struct resource *res;
-	struct resource *new_res;
+	struct resource *res, *new_res;
 	resource_size_t end;
 	int ret = -EINVAL;
 
@@ -1285,16 +1281,16 @@ int release_mem_region_adjustable(struct resource *parent,
 	/* The alloc_resource() result gets checked later */
 	new_res = alloc_resource(GFP_KERNEL);
 
-	p = &parent->child;
+	res = resource_first_child(&parent->child);
 	write_lock(&resource_lock);
 
-	while ((res = *p)) {
+	while ((res)) {
 		if (res->start >= end)
 			break;
 
 		/* look for the next resource if it does not fit into */
 		if (res->start > start || res->end < end) {
-			p = &res->sibling;
+			res = resource_sibling(res);
 			continue;
 		}
 
@@ -1302,14 +1298,14 @@ int release_mem_region_adjustable(struct resource *parent,
 			break;
 
 		if (!(res->flags & IORESOURCE_BUSY)) {
-			p = &res->child;
+			res = resource_first_child(&res->child);
 			continue;
 		}
 
 		/* found the target resource; let's adjust accordingly */
 		if (res->start == start && res->end == end) {
 			/* free the whole entry */
-			*p = res->sibling;
+			list_del(&res->sibling);
 			free_resource(res);
 			ret = 0;
 		} else if (res->start == start && res->end != end) {
@@ -1332,14 +1328,13 @@ int release_mem_region_adjustable(struct resource *parent,
 			new_res->flags = res->flags;
 			new_res->desc = res->desc;
 			new_res->parent = res->parent;
-			new_res->sibling = res->sibling;
-			new_res->child = NULL;
+			INIT_LIST_HEAD(&new_res->child);
 
 			ret = __adjust_resource(res, res->start,
 						start - res->start);
 			if (ret)
 				break;
-			res->sibling = new_res;
+			list_add(&new_res->sibling, &res->sibling);
 			new_res = NULL;
 		}
 
@@ -1520,7 +1515,7 @@ static int __init reserve_setup(char *str)
 			res->end = io_start + io_num - 1;
 			res->flags |= IORESOURCE_BUSY;
 			res->desc = IORES_DESC_NONE;
-			res->child = NULL;
+			INIT_LIST_HEAD(&res->child);
 			if (request_resource(parent, res) == 0)
 				reserved = x+1;
 		}
@@ -1540,7 +1535,7 @@ int iomem_map_sanity_check(resource_size_t addr, unsigned long size)
 	loff_t l;
 
 	read_lock(&resource_lock);
-	for (p = p->child; p ; p = r_next(NULL, p, &l)) {
+	for (p = resource_first_child(&p->child); p; p = r_next(NULL, p, &l)) {
 		/*
 		 * We can probably skip the resources without
 		 * IORESOURCE_IO attribute?
@@ -1596,7 +1591,7 @@ bool iomem_is_exclusive(u64 addr)
 	addr = addr & PAGE_MASK;
 
 	read_lock(&resource_lock);
-	for (p = p->child; p ; p = r_next(NULL, p, &l)) {
+	for (p = resource_first_child(&p->child); p; p = r_next(NULL, p, &l)) {
 		/*
 		 * We can probably skip the resources without
 		 * IORESOURCE_IO attribute?
-- 
2.13.6

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Re: [PATCH v5 2/4] resource: Use list_head to link sibling resource

[kbuild test robot]

Hi Baoquan,

I love your patch! Yet something to improve:

[auto build test ERROR on linus/master]
[also build test ERROR on v4.17 next-20180608]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Baoquan-He/resource-Use-list_head-to-link-sibling-resource/20180612-113600
config: i386-tinyconfig (attached as .config)
compiler: gcc-7 (Debian 7.3.0-16) 7.3.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

All errors (new ones prefixed by >>):

   kernel/resource.c: In function 'reparent_resources':
>> kernel/resource.c:1005:26: error: passing argument 2 of 'list_add' from incompatible pointer type [-Werror=incompatible-pointer-types]
     list_add(&res->sibling, &p->sibling.prev);
                             ^
   In file included from include/linux/ioport.h:15:0,
                    from kernel/resource.c:14:
   include/linux/list.h:77:20: note: expected 'struct list_head *' but argument is of type 'struct list_head **'
    static inline void list_add(struct list_head *new, struct list_head *head)
                       ^~~~~~~~
   In file included from include/linux/list.h:9:0,
                    from include/linux/ioport.h:15,
                    from kernel/resource.c:14:
>> kernel/resource.c:1013:26: error: 'new' undeclared (first use in this function); did you mean 'net'?
     list_for_each_entry(p, &new->child, sibling) {
                             ^
   include/linux/kernel.h:963:26: note: in definition of macro 'container_of'
     void *__mptr = (void *)(ptr);     \
                             ^~~
   include/linux/list.h:377:2: note: in expansion of macro 'list_entry'
     list_entry((ptr)->next, type, member)
     ^~~~~~~~~~
   include/linux/list.h:464:13: note: in expansion of macro 'list_first_entry'
     for (pos = list_first_entry(head, typeof(*pos), member); \
                ^~~~~~~~~~~~~~~~
   kernel/resource.c:1013:2: note: in expansion of macro 'list_for_each_entry'
     list_for_each_entry(p, &new->child, sibling) {
     ^~~~~~~~~~~~~~~~~~~
   kernel/resource.c:1013:26: note: each undeclared identifier is reported only once for each function it appears in
     list_for_each_entry(p, &new->child, sibling) {
                             ^
   include/linux/kernel.h:963:26: note: in definition of macro 'container_of'
     void *__mptr = (void *)(ptr);     \
                             ^~~
   include/linux/list.h:377:2: note: in expansion of macro 'list_entry'
     list_entry((ptr)->next, type, member)
     ^~~~~~~~~~
   include/linux/list.h:464:13: note: in expansion of macro 'list_first_entry'
     for (pos = list_first_entry(head, typeof(*pos), member); \
                ^~~~~~~~~~~~~~~~
   kernel/resource.c:1013:2: note: in expansion of macro 'list_for_each_entry'
     list_for_each_entry(p, &new->child, sibling) {
     ^~~~~~~~~~~~~~~~~~~
   cc1: some warnings being treated as errors

vim +/list_add +1005 kernel/resource.c

   983	
   984	/*
   985	 * Reparent resource children of pr that conflict with res
   986	 * under res, and make res replace those children.
   987	 */
   988	int reparent_resources(struct resource *parent, struct resource *res)
   989	{
   990		struct resource *p, *first = NULL;
   991	
   992		list_for_each_entry(p, &parent->child, sibling) {
   993			if (p->end < res->start)
   994				continue;
   995			if (res->end < p->start)
   996				break;
   997			if (p->start < res->start || p->end > res->end)
   998				return -1;	/* not completely contained */
   999			if (first == NULL)
  1000				first = p;
  1001		}
  1002		if (first == NULL)
  1003			return -1;	/* didn't find any conflicting entries? */
  1004		res->parent = parent;
> 1005		list_add(&res->sibling, &p->sibling.prev);
  1006		INIT_LIST_HEAD(&res->child);
  1007	
  1008		/*
  1009		 * From first to p's previous sibling, they all fall into
  1010		 * res's region, change them as res's children.
  1011		 */
  1012		list_cut_position(&res->child, first->sibling.prev, res->sibling.prev);
> 1013		list_for_each_entry(p, &new->child, sibling) {
  1014	                p->parent = new;
  1015			pr_debug("PCI: Reparented %s %pR under %s\n",
  1016				 p->name, p, res->name);
  1017		}
  1018		return 0;
  1019	}
  1020	EXPORT_SYMBOL(reparent_resources);
  1021	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

Re: [PATCH v5 2/4] resource: Use list_head to link sibling resource

[kbuild test robot]

Hi Baoquan,

I love your patch! Perhaps something to improve:

[auto build test WARNING on linus/master]
[also build test WARNING on v4.17 next-20180608]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Baoquan-He/resource-Use-list_head-to-link-sibling-resource/20180612-113600
config: x86_64-randconfig-x011-201823 (attached as .config)
compiler: gcc-7 (Debian 7.3.0-16) 7.3.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

All warnings (new ones prefixed by >>):

   kernel/resource.c: In function 'reparent_resources':
   kernel/resource.c:1005:26: error: passing argument 2 of 'list_add' from incompatible pointer type [-Werror=incompatible-pointer-types]
     list_add(&res->sibling, &p->sibling.prev);
                             ^
   In file included from include/linux/ioport.h:15:0,
                    from kernel/resource.c:14:
   include/linux/list.h:77:20: note: expected 'struct list_head *' but argument is of type 'struct list_head **'
    static inline void list_add(struct list_head *new, struct list_head *head)
                       ^~~~~~~~
   In file included from include/linux/list.h:9:0,
                    from include/linux/ioport.h:15,
                    from kernel/resource.c:14:
   kernel/resource.c:1013:26: error: 'new' undeclared (first use in this function); did you mean 'net'?
     list_for_each_entry(p, &new->child, sibling) {
                             ^
   include/linux/kernel.h:963:26: note: in definition of macro 'container_of'
     void *__mptr = (void *)(ptr);     \
                             ^~~
   include/linux/list.h:377:2: note: in expansion of macro 'list_entry'
     list_entry((ptr)->next, type, member)
     ^~~~~~~~~~
   include/linux/list.h:464:13: note: in expansion of macro 'list_first_entry'
     for (pos = list_first_entry(head, typeof(*pos), member); \
                ^~~~~~~~~~~~~~~~
>> kernel/resource.c:1013:2: note: in expansion of macro 'list_for_each_entry'
     list_for_each_entry(p, &new->child, sibling) {
     ^~~~~~~~~~~~~~~~~~~
   kernel/resource.c:1013:26: note: each undeclared identifier is reported only once for each function it appears in
     list_for_each_entry(p, &new->child, sibling) {
                             ^
   include/linux/kernel.h:963:26: note: in definition of macro 'container_of'
     void *__mptr = (void *)(ptr);     \
                             ^~~
   include/linux/list.h:377:2: note: in expansion of macro 'list_entry'
     list_entry((ptr)->next, type, member)
     ^~~~~~~~~~
   include/linux/list.h:464:13: note: in expansion of macro 'list_first_entry'
     for (pos = list_first_entry(head, typeof(*pos), member); \
                ^~~~~~~~~~~~~~~~
>> kernel/resource.c:1013:2: note: in expansion of macro 'list_for_each_entry'
     list_for_each_entry(p, &new->child, sibling) {
     ^~~~~~~~~~~~~~~~~~~
   cc1: some warnings being treated as errors

vim +/list_for_each_entry +1013 kernel/resource.c

   983	
   984	/*
   985	 * Reparent resource children of pr that conflict with res
   986	 * under res, and make res replace those children.
   987	 */
   988	int reparent_resources(struct resource *parent, struct resource *res)
   989	{
   990		struct resource *p, *first = NULL;
   991	
   992		list_for_each_entry(p, &parent->child, sibling) {
   993			if (p->end < res->start)
   994				continue;
   995			if (res->end < p->start)
   996				break;
   997			if (p->start < res->start || p->end > res->end)
   998				return -1;	/* not completely contained */
   999			if (first == NULL)
  1000				first = p;
  1001		}
  1002		if (first == NULL)
  1003			return -1;	/* didn't find any conflicting entries? */
  1004		res->parent = parent;
  1005		list_add(&res->sibling, &p->sibling.prev);
  1006		INIT_LIST_HEAD(&res->child);
  1007	
  1008		/*
  1009		 * From first to p's previous sibling, they all fall into
  1010		 * res's region, change them as res's children.
  1011		 */
  1012		list_cut_position(&res->child, first->sibling.prev, res->sibling.prev);
> 1013		list_for_each_entry(p, &new->child, sibling) {
  1014	                p->parent = new;
  1015			pr_debug("PCI: Reparented %s %pR under %s\n",
  1016				 p->name, p, res->name);
  1017		}
  1018		return 0;
  1019	}
  1020	EXPORT_SYMBOL(reparent_resources);
  1021	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[PATCH v5 4/4] kexec_file: Load kernel at top of system RAM if required

[Baoquan He]

For kexec_file loading, if kexec_buf.top_down is 'true', the memory which
is used to load kernel/initrd/purgatory is supposed to be allocated from
top to down. This is what we have been doing all along in the old kexec
loading interface and the kexec loading is still default setting in some
distributions. However, the current kexec_file loading interface doesn't
do likt this. The function arch_kexec_walk_mem() it calls ignores checking
kexec_buf.top_down, but calls walk_system_ram_res() directly to go through
all resources of System RAM from bottom to up, to try to find memory region
which can contain the specific kexec buffer, then call locate_mem_hole_callback()
to allocate memory in that found memory region from top to down. This brings
confusion especially when KASLR is widely supported , users have to make clear
why kexec/kdump kernel loading position is different between these two
interfaces in order to exclude unnecessary noises. Hence these two interfaces
need be unified on behaviour.

Here add checking if kexec_buf.top_down is 'true' in arch_kexec_walk_mem(),
if yes, call the newly added walk_system_ram_res_rev() to find memory region
from top to down to load kernel.

Signed-off-by: Baoquan He <bhe-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Cc: Eric Biederman <ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
Cc: Vivek Goyal <vgoyal-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Cc: Dave Young <dyoung-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Cc: Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
Cc: Yinghai Lu <yinghai-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: kexec-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
---
 kernel/kexec_file.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index 75d8e7cf040e..7a66d9d5a534 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -518,6 +518,8 @@ int __weak arch_kexec_walk_mem(struct kexec_buf *kbuf,
 					   IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY,
 					   crashk_res.start, crashk_res.end,
 					   kbuf, func);
+	else if (kbuf->top_down)
+		return walk_system_ram_res_rev(0, ULONG_MAX, kbuf, func);
 	else
 		return walk_system_ram_res(0, ULONG_MAX, kbuf, func);
 }
-- 
2.13.6