Hi Tejun,
I am sorry, I don't take any test for the patch attached in previous mail, and it can't fix the bug completely, please ignore it
I provide a new patch attached in this mail which pass test and can fix the issue described below
__next_mem_range_rev() defined in mm/memblock.c doesn't Achieve desired purpose if parameter type_b ==NULL
This new patch can fix the issue and get the last reversed region contained in type_a rightly
The new patch is descripted as follows
From 0e242eda7696f176a9a2e585a1db01f0575b39c9 Mon Sep 17 00:00:00 2001
From: zijun_hu <zijun_hu@xxxxxxx>
Date: Mon, 25 Jul 2016 15:06:57 +0800
Subject: [PATCH] mm/memblock.c: fix index adjustment error in
__next_mem_range_rev()
fix region index adjustment error when parameter type_b of
__next_mem_range_rev() == NULL
Signed-off-by: zijun_hu <zijun_hu@xxxxxxx>
---
mm/memblock.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/mm/memblock.c b/mm/memblock.c
index ac12489..cc5aeab 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -991,7 +991,11 @@ void __init_memblock __next_mem_range_rev(u64 *idx, int nid, ulong flags,
if (*idx == (u64)ULLONG_MAX) {
idx_a = type_a->cnt - 1;
-idx_b = type_b->cnt;
+/* in order to get the last reversed region rightly */
+if (type_b != NULL)
+idx_b = type_b->cnt;
+else
+idx_b = 0;
}
for (; idx_a >= 0; idx_a--) {
@@ -1024,7 +1028,7 @@ void __init_memblock __next_mem_range_rev(u64 *idx, int nid, ulong flags,
*out_end = m_end;
if (out_nid)
*out_nid = m_nid;
-idx_a++;
+idx_a--;
*idx = (u32)idx_a | (u64)idx_b << 32;
return;
}
--
1.9.1
Zijun Hu
Tel: +86 021 3813 0008 Ext: 8556
F1 Building, 299 Kang Wei Road, Pudong New Area,
Shanghai 201315, China
htc.com
-----邮件原件-----
发件人: Tejun Heo [mailto:htejun@xxxxxxxxx] 代表 Tejun Heo
发送时间: 2016年7月26日 2:52
收件人: Zijun Hu(胡自軍)
抄送: akpm@xxxxxxxxxxxxxxxxxxxx; kuleshovmail@xxxxxxxxx; ard.biesheuvel@xxxxxxxxxx; tangchen@xxxxxxxxxxxxxx; weiyang@xxxxxxxxxxxxxxxxxx; dev@xxxxxxxxxx; david@xxxxxxxxxxxxxxxxxxxxx; linux-mm@xxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
主题: Re: [PATCH] mm/memblock.c: fix index adjustment error in __next_mem_range_rev()
On Mon, Jul 25, 2016 at 07:34:12AM +0000, zijun_hu@xxxxxxx wrote:
> Hi All,
> There is a bug in mm/memblock.c
> Could you review and phase-in this patch?
> Thanks a lot
>
> From 3abf1822d30f77f126bd7a3c09bb243d9c17a029 Mon Sep 17 00:00:00 2001
> From: zijun_hu <zijun_hu@xxxxxxx>
> Date: Mon, 25 Jul 2016 15:06:57 +0800
> Subject: [PATCH] mm/memblock.c: fix index adjustment error in
> __next_mem_range_rev()
>
> fix region index adjustment error when parameter type_b of
> __next_mem_range_rev() == NULL
>
> Signed-off-by: zijun_hu <zijun_hu@xxxxxxx>
> ---
> mm/memblock.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/memblock.c b/mm/memblock.c index ac12489..b14973e
> 100644
> --- a/mm/memblock.c
> +++ b/mm/memblock.c
> @@ -1024,7 +1024,7 @@ void __init_memblock __next_mem_range_rev(u64 *idx, int nid, ulong flags,
> *out_end = m_end;
> if (out_nid)
> *out_nid = m_nid;
> - idx_a++;
> + idx_a--;
Looks good to me. Do you happen to have a test case for this bug?
Thanks.
--
tejun
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Description: 0001-mm-memblock.c-fix-index-adjustment-error-in.patch