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* [PATCH v3 1/4] resource: Change __request_region to inherit from immediate parent
@ 2016-03-09 19:47 Toshi Kani
  2016-03-09 19:47 ` [PATCH v3 2/4] resource: Add remove_resource interface Toshi Kani
                   ` (2 more replies)
  0 siblings, 3 replies; 4+ messages in thread
From: Toshi Kani @ 2016-03-09 19:47 UTC (permalink / raw)
  To: mingo, bp, dan.j.williams, rjw, akpm
  Cc: linux-nvdimm, linux-acpi, linux-kernel, Toshi Kani

__request_region() sets 'flags' of a new resource from @parent
as it inherits the parent's attribute.  When a target resource
has a conflict, this function inserts the new resource entry
under the conflicted entry by updating @parent.  In this case,
the new resource entry needs to inherit attribute from the updated
parent.  This conflict is a typical case since __request_region()
is used to allocate a new resource from a specific resource range.

For instance, request_mem_region() calls __request_region() with
@parent set to &iomem_resource, which is the root entry of the
whole iomem range.  When this request results in inserting a new
entry "DEV-A" under "BUS-1", "DEV-A" needs to inherit from the
immediate parent "BUS-1" as it holds specific attribute for the
range.

root (&iomem_resource)
 :
 + "BUS-1"
    + "DEV-A"

Change __request_region() to set 'flags' and 'desc' of a new entry
from the immediate parent.

Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dan Williams <dan.j.williams@intel.com>
---
 kernel/resource.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/kernel/resource.c b/kernel/resource.c
index 4d46605..5a56e8f 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -1085,15 +1085,16 @@ struct resource * __request_region(struct resource *parent,
 	res->name = name;
 	res->start = start;
 	res->end = start + n - 1;
-	res->flags = resource_type(parent) | resource_ext_type(parent);
-	res->flags |= IORESOURCE_BUSY | flags;
-	res->desc = IORES_DESC_NONE;
 
 	write_lock(&resource_lock);
 
 	for (;;) {
 		struct resource *conflict;
 
+		res->flags = resource_type(parent) | resource_ext_type(parent);
+		res->flags |= IORESOURCE_BUSY | flags;
+		res->desc = parent->desc;
+
 		conflict = __request_resource(parent, res);
 		if (!conflict)
 			break;

^ permalink raw reply	[flat|nested] 4+ messages in thread
end of thread, other threads:[~2016-03-09 18:55 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-03-09 19:47 [PATCH v3 1/4] resource: Change __request_region to inherit from immediate parent Toshi Kani
2016-03-09 19:47 ` [PATCH v3 2/4] resource: Add remove_resource interface Toshi Kani
2016-03-09 19:47 ` [PATCH v3 3/4] resource: Export insert_resource and remove_resource Toshi Kani
2016-03-09 19:47 ` [PATCH v3 4/4] ACPI: Change NFIT driver to insert new resource Toshi Kani

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