path: root/include
diff options
authorToshi Kani <toshi.kani@hp.com>2013-04-29 15:08:19 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-04-29 15:54:37 -0700
commit825f787bb49676083b97c1de1f8f2f8f26b5c908 (patch)
treef0cda2ad649b442fffc064dc625aa85e2b005ae2 /include
parentae8e3a915aef5af5ace5936c56f05f0b1502ded1 (diff)
resource: add release_mem_region_adjustable()
Add release_mem_region_adjustable(), which releases a requested region from a currently busy memory resource. This interface adjusts the matched memory resource accordingly even if the requested region does not match exactly but still fits into. This new interface is intended for memory hot-delete. During bootup, memory resources are inserted from the boot descriptor table, such as EFI Memory Table and e820. Each memory resource entry usually covers the whole contigous memory range. Memory hot-delete request, on the other hand, may target to a particular range of memory resource, and its size can be much smaller than the whole contiguous memory. Since the existing release interfaces like __release_region() require a requested region to be exactly matched to a resource entry, they do not allow a partial resource to be released. This new interface is restrictive (i.e. release under certain conditions), which is consistent with other release interfaces, __release_region() and __release_resource(). Additional release conditions, such as an overlapping region to a resource entry, can be supported after they are confirmed as valid cases. There is no change to the existing interfaces since their restriction is valid for I/O resources. [akpm@linux-foundation.org: use GFP_ATOMIC under write_lock()] [akpm@linux-foundation.org: switch back to GFP_KERNEL, less buggily] [akpm@linux-foundation.org: remove unneeded and wrong kfree(), per Toshi] Signed-off-by: Toshi Kani <toshi.kani@hp.com> Reviewed-by : Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: David Rientjes <rientjes@google.com> Reviewed-by: Ram Pai <linuxram@us.ibm.com> Cc: T Makphaibulchoke <tmac@hp.com> Cc: Wen Congyang <wency@cn.fujitsu.com> Cc: Tang Chen <tangchen@cn.fujitsu.com> Cc: Jiang Liu <jiang.liu@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
1 files changed, 4 insertions, 0 deletions
diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index 85ac9b9b72a..89b7c24a36e 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -192,6 +192,10 @@ extern struct resource * __request_region(struct resource *,
extern int __check_region(struct resource *, resource_size_t, resource_size_t);
extern void __release_region(struct resource *, resource_size_t,
+extern int release_mem_region_adjustable(struct resource *, resource_size_t,
+ resource_size_t);
static inline int __deprecated check_region(resource_size_t s,
resource_size_t n)