linux-kernel - [RFC Part1 PATCH v3 09/17] resource: Consolidate resource walking code

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Date:   Mon, 24 Jul 2017 14:07:49 -0500
From:   Brijesh Singh <brijesh.singh@....com>
To:     linux-kernel@...r.kernel.org, x86@...nel.org,
        linux-efi@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
        kvm@...r.kernel.org
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H . Peter Anvin" <hpa@...or.com>, Borislav Petkov <bp@...e.de>,
        Andy Lutomirski <luto@...nel.org>,
        Tony Luck <tony.luck@...el.com>,
        Piotr Luc <piotr.luc@...el.com>,
        Tom Lendacky <thomas.lendacky@....com>,
        Fenghua Yu <fenghua.yu@...el.com>,
        Lu Baolu <baolu.lu@...ux.intel.com>,
        Reza Arbab <arbab@...ux.vnet.ibm.com>,
        David Howells <dhowells@...hat.com>,
        Matt Fleming <matt@...eblueprint.co.uk>,
        "Kirill A . Shutemov" <kirill.shutemov@...ux.intel.com>,
        Laura Abbott <labbott@...hat.com>,
        Ard Biesheuvel <ard.biesheuvel@...aro.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Eric Biederman <ebiederm@...ssion.com>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
        Jonathan Corbet <corbet@....net>,
        Dave Airlie <airlied@...hat.com>,
        Kees Cook <keescook@...omium.org>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Radim Krčmář <rkrcmar@...hat.com>,
        Arnd Bergmann <arnd@...db.de>, Tejun Heo <tj@...nel.org>,
        Christoph Lameter <cl@...ux.com>,
        Brijesh Singh <brijesh.singh@....com>
Subject: [RFC Part1 PATCH v3 09/17] resource: Consolidate resource walking code

From: Tom Lendacky <thomas.lendacky@....com>

The walk_iomem_res_desc(), walk_system_ram_res() and walk_system_ram_range()
functions each have much of the same code.  Create a new function that
consolidates the common code from these functions in one place to reduce
the amount of duplicated code.

Signed-off-by: Tom Lendacky <thomas.lendacky@....com>
Signed-off-by: Brijesh Singh <brijesh.singh@....com>
---
 kernel/resource.c | 53 ++++++++++++++++++++++++++---------------------------
 1 file changed, 26 insertions(+), 27 deletions(-)

diff --git a/kernel/resource.c b/kernel/resource.c
index 9b5f044..7b20b3e 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -397,9 +397,30 @@ static int find_next_iomem_res(struct resource *res, unsigned long desc,
 		res->start = p->start;
 	if (res->end > p->end)
 		res->end = p->end;
+	res->desc = p->desc;
 	return 0;
 }
 
+static int __walk_iomem_res_desc(struct resource *res, unsigned long desc,
+				 bool first_level_children_only,
+				 void *arg, int (*func)(u64, u64, void *))
+{
+	u64 orig_end = res->end;
+	int ret = -1;
+
+	while ((res->start < res->end) &&
+	       !find_next_iomem_res(res, desc, first_level_children_only)) {
+		ret = (*func)(res->start, res->end, arg);
+		if (ret)
+			break;
+
+		res->start = res->end + 1;
+		res->end = orig_end;
+	}
+
+	return ret;
+}
+
 /*
  * Walks through iomem resources and calls func() with matching resource
  * ranges. This walks through whole tree and not just first level children.
@@ -418,26 +439,12 @@ int walk_iomem_res_desc(unsigned long desc, unsigned long flags, u64 start,
 		u64 end, void *arg, int (*func)(u64, u64, void *))
 {
 	struct resource res;
-	u64 orig_end;
-	int ret = -1;
 
 	res.start = start;
 	res.end = end;
 	res.flags = flags;
-	orig_end = res.end;
-
-	while ((res.start < res.end) &&
-		(!find_next_iomem_res(&res, desc, false))) {
-
-		ret = (*func)(res.start, res.end, arg);
-		if (ret)
-			break;
-
-		res.start = res.end + 1;
-		res.end = orig_end;
-	}
 
-	return ret;
+	return __walk_iomem_res_desc(&res, desc, false, arg, func);
 }
 
 /*
@@ -451,22 +458,13 @@ int walk_system_ram_res(u64 start, u64 end, void *arg,
 				int (*func)(u64, u64, void *))
 {
 	struct resource res;
-	u64 orig_end;
-	int ret = -1;
 
 	res.start = start;
 	res.end = end;
 	res.flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
-	orig_end = res.end;
-	while ((res.start < res.end) &&
-		(!find_next_iomem_res(&res, IORES_DESC_NONE, true))) {
-		ret = (*func)(res.start, res.end, arg);
-		if (ret)
-			break;
-		res.start = res.end + 1;
-		res.end = orig_end;
-	}
-	return ret;
+
+	return __walk_iomem_res_desc(&res, IORES_DESC_NONE, true,
+				     arg, func);
 }
 
 #if !defined(CONFIG_ARCH_HAS_WALK_MEMORY)
@@ -508,6 +506,7 @@ static int __is_ram(unsigned long pfn, unsigned long nr_pages, void *arg)
 {
 	return 1;
 }
+
 /*
  * This generic page_is_ram() returns true if specified address is
  * registered as System RAM in iomem_resource list.
-- 
2.9.4