netdev - Re: [PATCH v6 08/28] cxl: add functions for resource request/release by a driver

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Message-ID: <a7782f8b-30a1-97cf-8bf3-707d5b4f0984@amd.com>
Date: Mon, 9 Dec 2024 09:07:37 +0000
From: Alejandro Lucero Palau <alucerop@....com>
To: Kalesh Anakkur Purayil <kalesh-anakkur.purayil@...adcom.com>,
 alejandro.lucero-palau@....com
Cc: linux-cxl@...r.kernel.org, netdev@...r.kernel.org,
 dan.j.williams@...el.com, martin.habets@...inx.com, edward.cree@....com,
 davem@...emloft.net, kuba@...nel.org, pabeni@...hat.com,
 edumazet@...gle.com, dave.jiang@...el.com
Subject: Re: [PATCH v6 08/28] cxl: add functions for resource request/release
 by a driver


On 12/6/24 04:00, Kalesh Anakkur Purayil wrote:
> On Tue, Dec 3, 2024 at 12:11 AM <alejandro.lucero-palau@....com> wrote:
>> From: Alejandro Lucero <alucerop@....com>
>>
>> Create accessors for an accel driver requesting and releasing a resource.
>>
>> Signed-off-by: Alejandro Lucero <alucerop@....com>
>> Reviewed-by: Ben Cheatham <benjamin.cheatham@....com>
>> ---
>>   drivers/cxl/core/memdev.c | 51 +++++++++++++++++++++++++++++++++++++++
>>   include/cxl/cxl.h         |  2 ++
>>   2 files changed, 53 insertions(+)
>>
>> diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c
>> index 8257993562b6..1d43fa60525b 100644
>> --- a/drivers/cxl/core/memdev.c
>> +++ b/drivers/cxl/core/memdev.c
>> @@ -744,6 +744,57 @@ int cxl_set_resource(struct cxl_dev_state *cxlds, struct resource res,
>>   }
>>   EXPORT_SYMBOL_NS_GPL(cxl_set_resource, CXL);
>>
>> +int cxl_request_resource(struct cxl_dev_state *cxlds, enum cxl_resource type)
>> +{
>> +       int rc;
>> +
>> +       switch (type) {
>> +       case CXL_RES_RAM:
>> +               if (!resource_size(&cxlds->ram_res)) {
>> +                       dev_err(cxlds->dev,
>> +                               "resource request for ram with size 0\n");
> This can fit in one line?


I do not think so. I goes beyond 80 chars.


>> +                       return -EINVAL;
>> +               }
>> +
>> +               rc = request_resource(&cxlds->dpa_res, &cxlds->ram_res);
>> +               break;
>> +       case CXL_RES_PMEM:
>> +               if (!resource_size(&cxlds->pmem_res)) {
>> +                       dev_err(cxlds->dev,
>> +                               "resource request for pmem with size 0\n");
> This can fit in one line?o


Same here.


>> +                       return -EINVAL;
>> +               }
>> +               rc = request_resource(&cxlds->dpa_res, &cxlds->pmem_res);
> As an optimization, you can return directly from here and thereby
> avoid the need of local variable "rc". In the default case, you are
> returning directly anyway.


Right. Cleaner code.

I'll do so.

Thanks!


>> +               break;
>> +       default:
>> +               dev_err(cxlds->dev, "unsupported resource type (%u)\n", type);
>> +               return -EINVAL;
>> +       }
>> +
>> +       return rc;
>> +}
>> +EXPORT_SYMBOL_NS_GPL(cxl_request_resource, CXL);
>> +
>> +int cxl_release_resource(struct cxl_dev_state *cxlds, enum cxl_resource type)
>> +{
>> +       int rc;
>> +
>> +       switch (type) {
>> +       case CXL_RES_RAM:
>> +               rc = release_resource(&cxlds->ram_res);
>> +               break;
>> +       case CXL_RES_PMEM:
>> +               rc = release_resource(&cxlds->pmem_res);
>> +               break;
>> +       default:
>> +               dev_err(cxlds->dev, "unknown resource type (%u)\n", type);
>> +               return -EINVAL;
>> +       }
>> +
>> +       return rc;
>> +}
>> +EXPORT_SYMBOL_NS_GPL(cxl_release_resource, CXL);
>> +
>>   static int cxl_memdev_release_file(struct inode *inode, struct file *file)
>>   {
>>          struct cxl_memdev *cxlmd =
>> diff --git a/include/cxl/cxl.h b/include/cxl/cxl.h
>> index 18fb01adcf19..44664c9928a4 100644
>> --- a/include/cxl/cxl.h
>> +++ b/include/cxl/cxl.h
>> @@ -42,4 +42,6 @@ bool cxl_pci_check_caps(struct cxl_dev_state *cxlds,
>>                          unsigned long *expected_caps,
>>                          unsigned long *current_caps);
>>   int cxl_pci_accel_setup_regs(struct pci_dev *pdev, struct cxl_dev_state *cxlds);
>> +int cxl_request_resource(struct cxl_dev_state *cxlds, enum cxl_resource type);
>> +int cxl_release_resource(struct cxl_dev_state *cxlds, enum cxl_resource type);
>>   #endif
>> --
>> 2.17.1
>>
>>
>