linux-kernel - Re: [PATCH 2/3] of/numa: fix a memory@ dt node can only contains one memory block

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Message-ID: <CAL_JsqJXu36qYMOZeWDnMQ8BnOxMrixv5N70hvTjDixhMCQKRw@mail.gmail.com>
Date:	Thu, 26 May 2016 23:20:55 -0500
From:	Rob Herring <robh@...nel.org>
To:	"Leizhen (ThunderTown)" <thunder.leizhen@...wei.com>
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 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.

Rob