Subject: [PATCH v2 4/5] kernel/resource: Introduce walk_system_ram_excluding_child_res()

From: Marc Zyngier <[email-masked]>
Date: Mon, 31 May 2021 10:57:19 +0100

Introduce a new helper called walk_system_ram_excluding_child_res(),
which does the same job as walk_system_ram_res() but excludes
overlapping child resources.

Again, nobody is interested in such a filtering, so no functional
change is expected.

Acked-by: Catalin Marinas <[email-masked]>
Reviewed-by: Ard Biesheuvel <[email-masked]>
Signed-off-by: Marc Zyngier <[email-masked]>
---
 include/linux/ioport.h |  3 +++
 kernel/resource.c      | 15 +++++++++++++++
 2 files changed, 18 insertions(+)

diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index 8359c50f9988..f9638d085349 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -320,6 +320,9 @@ extern int
 walk_system_ram_res(u64 start, u64 end, void *arg,
 		    int (*func)(struct resource *, void *));
 extern int
+walk_system_ram_excluding_child_res(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 0e4d2ca763cd..92b765eaba58 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -492,6 +492,21 @@ int walk_system_ram_res(u64 start, u64 end, void *arg,
 				     false, arg, func);
 }
 
+/*
+ * This function calls the @func callback against all memory ranges of type
+ * System RAM which are marked as IORESOURCE_SYSTEM_RAM and IORESOUCE_BUSY,
+ * excluding RAM ranges that have overlapping child resources.
+ * Same constraints as @walk_system_ram_res apply.
+ */
+int walk_system_ram_excluding_child_res(u64 start, u64 end, void *arg,
+					int (*func)(struct resource *, void *))
+{
+	unsigned long flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
+
+	return __walk_iomem_res_desc(start, end, flags, IORES_DESC_NONE,
+				     true, arg, func);
+}
+
 /*
  * This function calls the @func callback against all memory ranges, which
  * are ranges marked as IORESOURCE_MEM and IORESOUCE_BUSY.
-- 
2.30.2

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