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Message-ID: <5747F16B.5050404@huawei.com>
Date: Fri, 27 May 2016 15:04:11 +0800
From: "Leizhen (ThunderTown)" <thunder.leizhen@...wei.com>
To: Rob Herring <robh@...nel.org>
CC: Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will.deacon@....com>,
linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
Ganapatrao Kulkarni <gkulkarni@...iumnetworks.com>,
Robert Richter <rrichter@...ium.com>,
"David Daney" <david.daney@...ium.com>,
Frank Rowand <frowand.list@...il.com>,
"Grant Likely" <grant.likely@...aro.org>,
devicetree <devicetree@...r.kernel.org>,
linux-kernel <linux-kernel@...r.kernel.org>,
Zefan Li <lizefan@...wei.com>, Xinwei Hu <huxinwei@...wei.com>,
Tianhong Ding <dingtianhong@...wei.com>,
Hanjun Guo <guohanjun@...wei.com>
Subject: Re: [PATCH 2/3] of/numa: fix a memory@ dt node can only contains one
memory block
On 2016/5/27 12:20, Rob Herring wrote:
> On Thu, May 26, 2016 at 10:36 PM, Leizhen (ThunderTown)
> <thunder.leizhen@...wei.com> wrote:
>>
>>
>> On 2016/5/26 21:13, Rob Herring wrote:
>>> On Thu, May 26, 2016 at 10:43:58AM +0800, Zhen Lei wrote:
>>>> For a normal memory@ devicetree node, its reg property can contains more
>>>> memory blocks.
>>>>
>>>> Because we don't known how many memory blocks maybe contained, so we try
>>>> from index=0, increase 1 until error returned(the end).
>>>>
>>>> Signed-off-by: Zhen Lei <thunder.leizhen@...wei.com>
>>>> ---
>>>> drivers/of/of_numa.c | 30 ++++++++++++++++++++----------
>>>> 1 file changed, 20 insertions(+), 10 deletions(-)
>>>>
>>>> diff --git a/drivers/of/of_numa.c b/drivers/of/of_numa.c
>>>> index 21d831f..2c5f249 100644
>>>> --- a/drivers/of/of_numa.c
>>>> +++ b/drivers/of/of_numa.c
>>>> @@ -63,7 +63,7 @@ static int __init of_numa_parse_memory_nodes(void)
>>>> struct device_node *np = NULL;
>>>> struct resource rsrc;
>>>> u32 nid;
>>>> - int r = 0;
>>>> + int i, r = 0;
>>>>
>>>> for (;;) {
>>>> np = of_find_node_by_type(np, "memory");
>>>> @@ -82,17 +82,27 @@ static int __init of_numa_parse_memory_nodes(void)
>>>> /* some other error */
>>>> break;
>>>>
>>>> - r = of_address_to_resource(np, 0, &rsrc);
>>>> - if (r) {
>>>> - pr_err("NUMA: bad reg property in memory node\n");
>>>> - break;
>>>> + for (i = 0; ; i++) {
>>>> + r = of_address_to_resource(np, i, &rsrc);
>>>> + if (r) {
>>>> + /* reached the end of of_address */
>>>> + if (i > 0) {
>>>> + r = 0;
>>>> + break;
>>>> + }
>>>> +
>>>> + pr_err("NUMA: bad reg property in memory node\n");
>>>> + goto finished;
>>>> + }
>>>> +
>>>> + r = numa_add_memblk(nid, rsrc.start,
>>>> + rsrc.end - rsrc.start + 1);
>>>> + if (r)
>>>> + goto finished;
>>>> }
>>>> -
>>>> - r = numa_add_memblk(nid, rsrc.start,
>>>> - rsrc.end - rsrc.start + 1);
>>>> - if (r)
>>>> - break;
>>>> }
>>>> +
>>>> +finished:
>>>> of_node_put(np);
>>>
>>> This function can be simplified down to:
>>>
>>> for_each_node_by_type(np, "memory") {
>> OK, That's good.
>>
>>> r = of_property_read_u32(np, "numa-node-id", &nid);
>>> if (r == -EINVAL)
>>> /*
>>> * property doesn't exist if -EINVAL, continue
>>> * looking for more memory nodes with
>>> * "numa-node-id" property
>>> */
>>> continue;
>> Hi, everybody:
>> If some "memory" node contains "numa-node-id", but some others missed. Can we simply ignored it?
>> I think we should break out too, and faking to only have node0.
>
> Continuing to work is probably better than not.
>
>>
>>> else if (r)
>>> /* some other error */
>>> break;
>>>
>>> r = of_address_to_resource(np, 0, &rsrc);
>>> for (i = 0; !r; i++, r = of_address_to_resource(np, i,
>>
>> But r(non-zero) is just break this loop, the original is break the outer for (;;) loop
>
> It is not really the kernel's job to validate the DT. If there's
> random things in it then kernel's behavior is undefined.
>
>>
>> How about as below?
>>
>> for_each_node_by_type(np, "memory") {
>> ... ...
>>
>> for (i = 0; !of_address_to_resource(np, i, &rsrc); i++) {
>> r = numa_add_memblk(nid, rsrc.start,
>> rsrc.end - rsrc.start + 1);
>> if (r)
>> goto finished;
>> }
>>
>> if (!i)
>> pr_err("NUMA: bad reg property in memory node\n");
>> }
>>
>> finished:
>
> Please try to avoid the goto. You can check r in the outer loop too.
OK. I have rewritten this function according to your advice.
for_each_node_by_type(np, "memory") {
r = of_property_read_u32(np, "numa-node-id", &nid);
if (r == -EINVAL)
/*
* property doesn't exist if -EINVAL, continue
* looking for more memory nodes with
* "numa-node-id" property
*/
continue;
//I deleted the break of "some other error", and it will break in below "if (!i || r)" branch
for (i = 0; !r && !of_address_to_resource(np, i, &rsrc); i++)
r = numa_add_memblk(nid, rsrc.start,
rsrc.end - rsrc.start + 1);
if (!i || r) {
of_node_put(np); //I moved here, so that it looks more clear. Because in the normal use of for_each_node_by_type, of_node_put is not required
pr_err("NUMA: bad property in memory node\n"); //Deleted "reg", so that it's suitable or harmless for other error cases
break;
}
}
return r;
>
> Rob
>
> .
>
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