linux-kernel - Re: [PATCH] cxl/region: Fix memregion leaks in devm_cxl_add

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Date: Tue, 7 May 2024 05:28:37 +0000
From: "Zhijian Li (Fujitsu)" <lizhijian@...itsu.com>
To: Dan Williams <dan.j.williams@...el.com>, Ira Weiny <ira.weiny@...el.com>,
	"dave@...olabs.net" <dave@...olabs.net>, "jonathan.cameron@...wei.com"
	<Jonathan.Cameron@...wei.com>, "dave.jiang@...el.com" <dave.jiang@...el.com>,
	"alison.schofield@...el.com" <alison.schofield@...el.com>,
	"vishal.l.verma@...el.com" <vishal.l.verma@...el.com>,
	"linux-cxl@...r.kernel.org" <linux-cxl@...r.kernel.org>
CC: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] cxl/region: Fix memregion leaks in devm_cxl_add_region()



On 04/05/2024 00:07, Dan Williams wrote:
> Zhijian Li (Fujitsu) wrote:
>>> I'm not following what the problem is you are trying to fix.  This seems
>>> like it just moves the memregion_free() around a bit but the logic is the
>>> same.
>>
>> This patch not only memregion_free(id) out of cxl_region_alloc() but
>> also add an  extra memregion_free(id) in EINVAL case which led to a
>> memory leak previously
>>
> 
> I think I would prefer to just eliminate that failure case, something
> like:

It sounds good to me. I will update it in V2

Thanks
Zhijian


> 
> -- >8 --
> diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
> index 5c186e0a39b9..95ba32f8649c 100644
> --- a/drivers/cxl/core/region.c
> +++ b/drivers/cxl/core/region.c
> @@ -2352,15 +2352,6 @@ static struct cxl_region *devm_cxl_add_region(struct cxl_root_decoder *cxlrd,
>          struct device *dev;
>          int rc;
>   
> -       switch (mode) {
> -       case CXL_DECODER_RAM:
> -       case CXL_DECODER_PMEM:
> -               break;
> -       default:
> -               dev_err(&cxlrd->cxlsd.cxld.dev, "unsupported mode %d\n", mode);
> -               return ERR_PTR(-EINVAL);
> -       }
> -
>          cxlr = cxl_region_alloc(cxlrd, id);
>          if (IS_ERR(cxlr))
>                  return cxlr;
> @@ -2415,6 +2406,15 @@ static struct cxl_region *__create_region(struct cxl_root_decoder *cxlrd,
>   {
>          int rc;
>   
> +       switch (mode) {
> +       case CXL_DECODER_RAM:
> +       case CXL_DECODER_PMEM:
> +               break;
> +       default:
> +               dev_err(&cxlrd->cxlsd.cxld.dev, "unsupported mode %d\n", mode);
> +               return ERR_PTR(-EINVAL);
> +       }
> +
>          rc = memregion_alloc(GFP_KERNEL);
>          if (rc < 0)
>                  return ERR_PTR(rc);
>