Re: [PATCH] kernel/resource: make iomem_resource implicit in release_mem_region_adjustable()

[Wei Yang]

On Wed, Sep 16, 2020 at 09:30:41AM +0200, David Hildenbrand wrote:
>"mem" in the name already indicates the root, similar to
>release_mem_region() and devm_request_mem_region(). Make it implicit.
>The only single caller always passes iomem_resource, other parents are
>not applicable.
>

Looks good to me.

Reviewed-by: Wei Yang <richard.weiyang@xxxxxxxxxxxxxxxxx>

>Suggested-by: Wei Yang <richard.weiyang@xxxxxxxxxxxxxxxxx>
>Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
>Cc: Michal Hocko <mhocko@xxxxxxxx>
>Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
>Cc: Jason Gunthorpe <jgg@xxxxxxxx>
>Cc: Kees Cook <keescook@xxxxxxxxxxxx>
>Cc: Ard Biesheuvel <ardb@xxxxxxxxxx>
>Cc: Pankaj Gupta <pankaj.gupta.linux@xxxxxxxxx>
>Cc: Baoquan He <bhe@xxxxxxxxxx>
>Cc: Wei Yang <richard.weiyang@xxxxxxxxxxxxxxxxx>
>Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
>---
>
>Based on next-20200915. Follow up on
>	"[PATCH v4 0/8] selective merging of system ram resources" [1]
>That's in next-20200915. As noted during review of v2 by Wei [2].
>
>[1] https://lkml.kernel.org/r/20200911103459.10306-1-david@xxxxxxxxxx
>[2] https://lkml.kernel.org/r/20200915021012.GC2007@L-31X9LVDL-1304.local
>
>---
> include/linux/ioport.h | 3 +--
> kernel/resource.c      | 5 ++---
> mm/memory_hotplug.c    | 2 +-
> 3 files changed, 4 insertions(+), 6 deletions(-)
>
>diff --git a/include/linux/ioport.h b/include/linux/ioport.h
>index 7e61389dcb01..5135d4b86cd6 100644
>--- a/include/linux/ioport.h
>+++ b/include/linux/ioport.h
>@@ -251,8 +251,7 @@ extern struct resource * __request_region(struct resource *,
> extern void __release_region(struct resource *, resource_size_t,
> 				resource_size_t);
> #ifdef CONFIG_MEMORY_HOTREMOVE
>-extern void release_mem_region_adjustable(struct resource *, resource_size_t,
>-					  resource_size_t);
>+extern void release_mem_region_adjustable(resource_size_t, resource_size_t);
> #endif
> #ifdef CONFIG_MEMORY_HOTPLUG
> extern void merge_system_ram_resource(struct resource *res);
>diff --git a/kernel/resource.c b/kernel/resource.c
>index 7a91b935f4c2..ca2a666e4317 100644
>--- a/kernel/resource.c
>+++ b/kernel/resource.c
>@@ -1240,7 +1240,6 @@ EXPORT_SYMBOL(__release_region);
> #ifdef CONFIG_MEMORY_HOTREMOVE
> /**
>  * release_mem_region_adjustable - release a previously reserved memory region
>- * @parent: parent resource descriptor
>  * @start: resource start address
>  * @size: resource region size
>  *
>@@ -1258,9 +1257,9 @@ EXPORT_SYMBOL(__release_region);
>  *   assumes that all children remain in the lower address entry for
>  *   simplicity.  Enhance this logic when necessary.
>  */
>-void release_mem_region_adjustable(struct resource *parent,
>-				   resource_size_t start, resource_size_t size)
>+void release_mem_region_adjustable(resource_size_t start, resource_size_t size)
> {
>+	struct resource *parent = &iomem_resource;
> 	struct resource *new_res = NULL;
> 	bool alloc_nofail = false;
> 	struct resource **p;
>diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
>index 553c718226b3..7c5e4744ac51 100644
>--- a/mm/memory_hotplug.c
>+++ b/mm/memory_hotplug.c
>@@ -1764,7 +1764,7 @@ static int __ref try_remove_memory(int nid, u64 start, u64 size)
> 		memblock_remove(start, size);
> 	}
> 
>-	release_mem_region_adjustable(&iomem_resource, start, size);
>+	release_mem_region_adjustable(start, size);
> 
> 	try_offline_node(nid);
> 
>-- 
>2.26.2

-- 
Wei Yang
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