linux-kernel - [PATCH 1/3] mm, vmalloc: Only call setup_vmalloc_vm only in __get_vm_area

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Date:	Mon, 03 Jun 2013 23:31:39 +0800
From:	Zhang Yanfei <zhangyanfei.yes@...il.com>
To:	Andrew Morton <akpm@...ux-foundation.org>
CC:	Joonsoo Kim <iamjoonsoo.kim@....com>,
	Joonsoo Kim <js1304@...il.com>, Linux MM <linux-mm@...ck.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: [PATCH 1/3] mm, vmalloc: Only call setup_vmalloc_vm only in __get_vm_area_node

From: Zhang Yanfei <zhangyanfei@...fujitsu.com>

Now for insert_vmalloc_vm, it only calls the two functions:
- setup_vmalloc_vm: fill vm_struct and vmap_area instances
- clear_vm_unlist: clear VM_UNLIST bit in vm_struct->flags

So in function __get_vm_area_node, if VM_UNLIST bit unset
in flags, that is the else branch here, we don't need to
clear VM_UNLIST bit for vm->flags since this bit is obviously
not set. That is to say, we could only call setup_vmalloc_vm
instead of insert_vmalloc_vm here. And then we could even
remove the if test here.

Signed-off-by: Zhang Yanfei <zhangyanfei@...fujitsu.com>
---
 mm/vmalloc.c |   11 +----------
 1 files changed, 1 insertions(+), 10 deletions(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index d365724..6580c76 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1367,16 +1367,7 @@ static struct vm_struct *__get_vm_area_node(unsigned long size,
 		return NULL;
 	}
 
-	/*
-	 * When this function is called from __vmalloc_node_range,
-	 * we add VM_UNLIST flag to avoid accessing uninitialized
-	 * members of vm_struct such as pages and nr_pages fields.
-	 * They will be set later.
-	 */
-	if (flags & VM_UNLIST)
-		setup_vmalloc_vm(area, va, flags, caller);
-	else
-		insert_vmalloc_vm(area, va, flags, caller);
+	setup_vmalloc_vm(area, va, flags, caller);
 
 	return area;
 }
-- 
1.7.1
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