+Nico who has been working on tinification of the kernel.
On Mon, Apr 9, 2018 at 4:08 AM, Baoquan He <bhe@xxxxxxxxxx> wrote:
> The struct resource uses singly linked list to link siblings. It's not
> easy to do reverse iteration on sibling list. So replace it with list_head.
Why is reverse iteration needed?
> And code refactoring makes codes in kernel/resource.c more readable than
> pointer operation.
resource_for_each_* helpers could solve that without the size increase.
> Besides, type of member variables of struct resource, sibling and child, are
> changed from 'struct resource *' to 'struct list_head'. Kernel size will
> increase because of those statically defined struct resource instances.
The DT struct device_node also has the same tree structure with
parent, child, sibling pointers and converting to list_head had been
on the todo list for a while. ACPI also has some tree walking
functions (drivers/acpi/acpica/pstree.c). Perhaps there should be a
common tree struct and helpers defined either on top of list_head or a
new struct if that saves some size.
>
> Signed-off-by: Baoquan He <bhe@xxxxxxxxxx>
> ---
> v2->v3:
> Make sibling() and first_child() global so that they can be called
> out of kernel/resource.c to simplify code.
These should probably be inline functions. Or exported if not.
>
> Fix several code bugs found by kbuild test robot.
>
> Got report from lkp that kernel size increased. It's on purpose since
> the type change of sibling and child inside struct resource{}. For
> each struct resource variable, it will cost another 16 bytes on x86 64.
The size increase should be mentioned in the commit log. More
generally, the size increase is 2 pointers.
Rob
>
> arch/sparc/kernel/ioport.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/e820.c | 2 +-
> 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 | 6 +-
> kernel/resource.c | 193 ++++++++++++++--------------
> 15 files changed, 149 insertions(+), 149 deletions(-)
>
> diff --git a/arch/sparc/kernel/ioport.c b/arch/sparc/kernel/ioport.c
> index 3bcef9ce74df..4e91fbbbedcc 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/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 bc65c4d79c1f..7ba8a25520d9 100644
> --- a/drivers/hv/vmbus_drv.c
> +++ b/drivers/hv/vmbus_drv.c
> @@ -1413,9 +1413,8 @@ 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) {
>
> @@ -1462,44 +1461,36 @@ 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) {
> @@ -1508,10 +1499,9 @@ 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;
> @@ -1597,7 +1587,8 @@ 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;
>
> @@ -1640,7 +1631,8 @@ 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/e820.c b/drivers/nvdimm/e820.c
> index 6f9a6ffd7cde..513e661bb0d8 100644
> --- a/drivers/nvdimm/e820.c
> +++ b/drivers/nvdimm/e820.c
> @@ -53,7 +53,7 @@ static int e820_pmem_probe(struct platform_device *pdev)
> goto err;
> platform_set_drvdata(pdev, nvdimm_bus);
>
> - for (p = iomem_resource.child; p ; p = p->sibling) {
> + list_for_each_entry(p, &iomem_resource.child, sibling) {
> struct nd_region_desc ndr_desc;
>
> if (p->desc != IORES_DESC_PERSISTENT_MEMORY_LEGACY)
> diff --git a/drivers/nvdimm/namespace_devs.c b/drivers/nvdimm/namespace_devs.c
> index 658ada497be0..bcbdf5335909 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 = 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 = 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 184e070d50a2..1dc0b2370bd1 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..84f04418ae0b 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(first_child(&r->child), d+2);
> + lba_dump_res(sibling(r), d);
> }
>
>
> diff --git a/drivers/pci/host/vmd.c b/drivers/pci/host/vmd.c
> index 930a8fa08bd6..c3000af903ea 100644
> --- a/drivers/pci/host/vmd.c
> +++ b/drivers/pci/host/vmd.c
> @@ -520,14 +520,14 @@ 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 ac91b6fd0bcd..d162c77bec29 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 072784f55ea5..0d5e30004ca6 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 da0ebaec25f0..03d1510f03e0 100644
> --- a/include/linux/ioport.h
> +++ b/include/linux/ioport.h
> @@ -22,7 +22,8 @@ struct resource {
> const char *name;
> unsigned long flags;
> unsigned long desc;
> - struct resource *parent, *sibling, *child;
> + struct list_head child, sibling;
> + struct resource *parent;
> };
>
> /*
> @@ -189,6 +190,8 @@ extern int allocate_resource(struct resource *root, struct resource *new,
> resource_size_t,
> resource_size_t),
> void *alignf_data);
> +extern struct resource *sibling(struct resource *res);
> +extern struct resource *first_child(struct list_head *head);
> 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);
> @@ -215,7 +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)
> diff --git a/kernel/resource.c b/kernel/resource.c
> index e270b5048988..473c624606f9 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 +61,32 @@ 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);
>
> +struct resource *sibling(struct resource *res)
> +{
> + if (res->parent && !list_is_last(&res->sibling, &res->parent->child))
> + return list_next_entry(res, sibling);
> + return NULL;
> +}
> +
> +struct resource *first_child(struct list_head *head)
> +{
> + return list_first_entry_or_null(head, struct resource, sibling);
> +}
> +
> 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 sibling(p);
>
> - if (p->child)
> - return p->child;
> - while (!p->sibling && p->parent)
> + if (!list_empty(&p->child))
> + return first_child(&p->child);
> + while (!sibling(p) && p->parent)
> p = p->parent;
> - return p->sibling;
> + return sibling(p);
> }
>
> static void *r_next(struct seq_file *m, void *v, loff_t *pos)
> @@ -90,7 +106,7 @@ static void *r_start(struct seq_file *m, loff_t *pos)
> struct resource *p = m->private;
> loff_t l = 0;
> read_lock(&resource_lock);
> - for (p = p->child; p && l < *pos; p = r_next(m, p, &l))
> + for (p = first_child(&p->child); p && l < *pos; p = r_next(m, p, &l))
> ;
> return p;
> }
> @@ -186,8 +202,7 @@ 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);
> @@ -199,10 +214,9 @@ 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 = first_child(&bootmem_resource_free);
> + if (res)
> + list_del(&res->sibling);
> spin_unlock(&bootmem_resource_lock);
>
> if (res)
> @@ -210,6 +224,8 @@ 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;
> }
>
> @@ -218,7 +234,7 @@ 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;
> @@ -226,64 +242,62 @@ 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);
> @@ -292,6 +306,8 @@ 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)
> @@ -376,7 +392,8 @@ 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 = 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))
> @@ -564,7 +581,7 @@ 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)));
> @@ -618,7 +635,7 @@ 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 = first_child(&root->child);
> struct resource tmp = *new, avail, alloc;
>
> tmp.start = root->start;
> @@ -628,7 +645,7 @@ 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 = sibling(this);
> }
> for(;;) {
> if (this)
> @@ -663,7 +680,7 @@ next: if (!this || this->end == root->end)
>
> if (this != old)
> tmp.start = this->end + 1;
> - this = this->sibling;
> + this = sibling(this);
> }
> return -EBUSY;
> }
> @@ -707,7 +724,7 @@ static int reallocate_resource(struct resource *root, struct resource *old,
> goto out;
> }
>
> - if (old->child) {
> + if (!list_empty(&old->child)) {
> err = -EBUSY;
> goto out;
> }
> @@ -788,7 +805,7 @@ 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;
> }
> @@ -821,32 +838,27 @@ static struct resource * __insert_resource(struct resource *parent, struct resou
> break;
> }
>
> - for (next = first; ; next = next->sibling) {
> + for (next = first; ; next = sibling(next)) {
> /* Partial overlap? Bad, and unfixable */
> if (next->start < new->start || next->end > new->end)
> return next;
> - if (!next->sibling)
> + if (!sibling(next))
> break;
> - if (next->sibling->start > new->end)
> + if (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;
> }
>
> @@ -968,19 +980,17 @@ 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 (sibling(res) && (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;
>
> @@ -1205,34 +1215,32 @@ 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 = 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 = 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 = sibling(res);
> }
>
> write_unlock(&resource_lock);
> @@ -1267,9 +1275,7 @@ 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;
>
> @@ -1280,16 +1286,16 @@ 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 = 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 = sibling(res);
> continue;
> }
>
> @@ -1297,14 +1303,14 @@ int release_mem_region_adjustable(struct resource *parent,
> break;
>
> if (!(res->flags & IORESOURCE_BUSY)) {
> - p = &res->child;
> + res = 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) {
> @@ -1327,14 +1333,13 @@ 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;
> }
>
> @@ -1515,7 +1520,7 @@ 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;
> }
> @@ -1535,7 +1540,7 @@ 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 = first_child(&p->child); p; p = r_next(NULL, p, &l)) {
> /*
> * We can probably skip the resources without
> * IORESOURCE_IO attribute?
> @@ -1591,7 +1596,7 @@ 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 = 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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