netdev - Re: [PATCH v2 03/15] cxl: add function for type2 resource request

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Message-ID: <20240822160730.00002102.zhiw@nvidia.com>
Date: Thu, 22 Aug 2024 16:07:30 +0300
From: Zhi Wang <zhiw@...dia.com>
To: <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>, <richard.hughes@....com>,
	Alejandro Lucero <alucerop@....com>, <targupta@...dia.com>,
	<zhiwang@...nel.org>
Subject: Re: [PATCH v2 03/15] cxl: add function for type2 resource request

On Mon, 15 Jul 2024 18:28:23 +0100
<alejandro.lucero-palau@....com> wrote:

> From: Alejandro Lucero <alucerop@....com>
> 
> Create a new function for a type2 device requesting a resource
> passing the opaque struct to work with.
> 
> Signed-off-by: Alejandro Lucero <alucerop@....com>
> ---
>  drivers/cxl/core/memdev.c          | 13 +++++++++++++
>  drivers/net/ethernet/sfc/efx_cxl.c |  7 ++++++-
>  include/linux/cxl_accel_mem.h      |  1 +
>  3 files changed, 20 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c
> index 61b5d35b49e7..04c3a0f8bc2e 100644
> --- a/drivers/cxl/core/memdev.c
> +++ b/drivers/cxl/core/memdev.c
> @@ -744,6 +744,19 @@ void cxl_accel_set_resource(struct cxl_dev_state
> *cxlds, struct resource res, }
>  EXPORT_SYMBOL_NS_GPL(cxl_accel_set_resource, CXL);
>  
> +int cxl_accel_request_resource(struct cxl_dev_state *cxlds, bool
> is_ram) +{
> +	int rc;
> +
> +	if (is_ram)
> +		rc = request_resource(&cxlds->dpa_res,
> &cxlds->ram_res);
> +	else
> +		rc = request_resource(&cxlds->dpa_res,
> &cxlds->pmem_res); +
> +	return rc;
> +}
> +EXPORT_SYMBOL_NS_GPL(cxl_accel_request_resource, CXL);
> +

Hi Alejandro:

Since we only have cxl_accel_request_resource() here, how is
the resource going to be released? e.g. in an error handling path. 

Thanks,
Zhi.

>  static int cxl_memdev_release_file(struct inode *inode, struct file
> *file) {
>  	struct cxl_memdev *cxlmd =
> diff --git a/drivers/net/ethernet/sfc/efx_cxl.c
> b/drivers/net/ethernet/sfc/efx_cxl.c index 10c4fb915278..9cefcaf3caca
> 100644 --- a/drivers/net/ethernet/sfc/efx_cxl.c
> +++ b/drivers/net/ethernet/sfc/efx_cxl.c
> @@ -48,8 +48,13 @@ void efx_cxl_init(struct efx_nic *efx)
>  	res = DEFINE_RES_MEM_NAMED(0, EFX_CTPIO_BUFFER_SIZE, "ram");
>  	cxl_accel_set_resource(cxl->cxlds, res, CXL_ACCEL_RES_RAM);
>  
> -	if (cxl_pci_accel_setup_regs(pci_dev, cxl->cxlds))
> +	if (cxl_pci_accel_setup_regs(pci_dev, cxl->cxlds)) {
>  		pci_info(pci_dev, "CXL accel setup regs failed");
> +		return;
> +	}
> +
> +	if (cxl_accel_request_resource(cxl->cxlds, true))
> +		pci_info(pci_dev, "CXL accel resource request
> failed"); }
>  
>  
> diff --git a/include/linux/cxl_accel_mem.h
> b/include/linux/cxl_accel_mem.h index ca7af4a9cefc..c7b254edc096
> 100644 --- a/include/linux/cxl_accel_mem.h
> +++ b/include/linux/cxl_accel_mem.h
> @@ -20,4 +20,5 @@ void cxl_accel_set_serial(cxl_accel_state *cxlds,
> u64 serial); void cxl_accel_set_resource(struct cxl_dev_state *cxlds,
> struct resource res, enum accel_resource);
>  int cxl_pci_accel_setup_regs(struct pci_dev *pdev, struct
> cxl_dev_state *cxlds); +int cxl_accel_request_resource(struct
> cxl_dev_state *cxlds, bool is_ram); #endif