Patchwork [v2] PCI: endpoint: functions: Use kmemdup instead of duplicating its function

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Submitter Wen Yang
Date Dec. 6, 2018, 12:52 p.m.
Message ID <20181206125225.9497-1-wen.yang99@zte.com.cn>
Download mbox | patch
Permalink /patch/674099/
State New
Headers show

Comments

Wen Yang - Dec. 6, 2018, 12:52 p.m.
kmemdup has implemented the function that kmalloc() + memcpy().
We prefer to kmemdup rather than code opened implementation.

This issue was detected with the help of coccinelle.

Signed-off-by: Wen Yang <wen.yang99@zte.com.cn>
CC: Kishon Vijay Abraham I <kishon@ti.com>
CC: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
CC: Bjorn Helgaas <bhelgaas@google.com>
CC: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
CC: Niklas Cassel <niklas.cassel@axis.com>
CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CC: Cyrille Pitchen <cyrille.pitchen@free-electrons.com>
CC: linux-pci@vger.kernel.org (open list:PCI ENDPOINT SUBSYSTEM)
CC: linux-kernel@vger.kernel.org (open list)
---
 drivers/pci/endpoint/functions/pci-epf-test.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)
Lorenzo Pieralisi - Feb. 8, 2019, 12:20 p.m.
On Thu, Dec 06, 2018 at 08:52:25PM +0800, Wen Yang wrote:
> kmemdup has implemented the function that kmalloc() + memcpy().
> We prefer to kmemdup rather than code opened implementation.
> 
> This issue was detected with the help of coccinelle.
> 
> Signed-off-by: Wen Yang <wen.yang99@zte.com.cn>
> CC: Kishon Vijay Abraham I <kishon@ti.com>
> CC: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> CC: Bjorn Helgaas <bhelgaas@google.com>
> CC: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
> CC: Niklas Cassel <niklas.cassel@axis.com>
> CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> CC: Cyrille Pitchen <cyrille.pitchen@free-electrons.com>
> CC: linux-pci@vger.kernel.org (open list:PCI ENDPOINT SUBSYSTEM)
> CC: linux-kernel@vger.kernel.org (open list)
> ---
>  drivers/pci/endpoint/functions/pci-epf-test.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)

Kishon,

this looks OK to me, anything I am missing ?

Lorenzo

> diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
> index 3e86fa3c7da3..8df6c019f8a2 100644
> --- a/drivers/pci/endpoint/functions/pci-epf-test.c
> +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
> @@ -169,14 +169,12 @@ static int pci_epf_test_read(struct pci_epf_test *epf_test)
>  		goto err_addr;
>  	}
>  
> -	buf = kzalloc(reg->size, GFP_KERNEL);
> +	buf = kmemdup(src_addr, reg->size, GFP_KERNEL);
>  	if (!buf) {
>  		ret = -ENOMEM;
>  		goto err_map_addr;
>  	}
>  
> -	memcpy(buf, src_addr, reg->size);
> -
>  	crc32 = crc32_le(~0, buf, reg->size);
>  	if (crc32 != reg->checksum)
>  		ret = -EIO;
> -- 
> 2.19.1
>
Kishon Vijay Abraham I - Feb. 11, 2019, 5:48 a.m.
Hi Lorenzo,

On 08/02/19 5:50 PM, Lorenzo Pieralisi wrote:
> On Thu, Dec 06, 2018 at 08:52:25PM +0800, Wen Yang wrote:
>> kmemdup has implemented the function that kmalloc() + memcpy().
>> We prefer to kmemdup rather than code opened implementation.
>>
>> This issue was detected with the help of coccinelle.
>>
>> Signed-off-by: Wen Yang <wen.yang99@zte.com.cn>
>> CC: Kishon Vijay Abraham I <kishon@ti.com>
>> CC: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
>> CC: Bjorn Helgaas <bhelgaas@google.com>
>> CC: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
>> CC: Niklas Cassel <niklas.cassel@axis.com>
>> CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>> CC: Cyrille Pitchen <cyrille.pitchen@free-electrons.com>
>> CC: linux-pci@vger.kernel.org (open list:PCI ENDPOINT SUBSYSTEM)
>> CC: linux-kernel@vger.kernel.org (open list)
>> ---
>>  drivers/pci/endpoint/functions/pci-epf-test.c | 4 +---
>>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> Kishon,
> 
> this looks OK to me, anything I am missing ?

For the existing code this might seem the right thing to do but ideally the
memcpy here should be changed to memcpy_fromio/memcpy_toio.

Also later when we plan to use DMA (on the endpoint) for data transfer, we have
to use kzalloc and dma_map_single APIs.

So maybe the right thing would be to just fix it to use memcpy_fromio here.

Thanks
Kishon
> 
> Lorenzo
> 
>> diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
>> index 3e86fa3c7da3..8df6c019f8a2 100644
>> --- a/drivers/pci/endpoint/functions/pci-epf-test.c
>> +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
>> @@ -169,14 +169,12 @@ static int pci_epf_test_read(struct pci_epf_test *epf_test)
>>  		goto err_addr;
>>  	}
>>  
>> -	buf = kzalloc(reg->size, GFP_KERNEL);
>> +	buf = kmemdup(src_addr, reg->size, GFP_KERNEL);
>>  	if (!buf) {
>>  		ret = -ENOMEM;
>>  		goto err_map_addr;
>>  	}
>>  
>> -	memcpy(buf, src_addr, reg->size);
>> -
>>  	crc32 = crc32_le(~0, buf, reg->size);
>>  	if (crc32 != reg->checksum)
>>  		ret = -EIO;
>> -- 
>> 2.19.1
>>
Gustavo Pimentel - Feb. 11, 2019, 9:15 a.m.
On 11/02/2019 05:48, Kishon Vijay Abraham I wrote:
> Hi Lorenzo,
> 
> On 08/02/19 5:50 PM, Lorenzo Pieralisi wrote:
>> On Thu, Dec 06, 2018 at 08:52:25PM +0800, Wen Yang wrote:
>>> kmemdup has implemented the function that kmalloc() + memcpy().
>>> We prefer to kmemdup rather than code opened implementation.
>>>
>>> This issue was detected with the help of coccinelle.
>>>
>>> Signed-off-by: Wen Yang <wen.yang99@zte.com.cn>
>>> CC: Kishon Vijay Abraham I <kishon@ti.com>
>>> CC: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
>>> CC: Bjorn Helgaas <bhelgaas@google.com>
>>> CC: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
>>> CC: Niklas Cassel <niklas.cassel@axis.com>
>>> CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>>> CC: Cyrille Pitchen <cyrille.pitchen@free-electrons.com>
>>> CC: linux-pci@vger.kernel.org (open list:PCI ENDPOINT SUBSYSTEM)
>>> CC: linux-kernel@vger.kernel.org (open list)
>>> ---
>>>  drivers/pci/endpoint/functions/pci-epf-test.c | 4 +---
>>>  1 file changed, 1 insertion(+), 3 deletions(-)
>>
>> Kishon,
>>
>> this looks OK to me, anything I am missing ?
> 
> For the existing code this might seem the right thing to do but ideally the
> memcpy here should be changed to memcpy_fromio/memcpy_toio.
> 
> Also later when we plan to use DMA (on the endpoint) for data transfer, we have
> to use kzalloc and dma_map_single APIs.

Are you considering to use the eDMA driver that I'm developing?

> 
> So maybe the right thing would be to just fix it to use memcpy_fromio here.
> 
> Thanks
> Kishon
>>
>> Lorenzo
>>
>>> diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
>>> index 3e86fa3c7da3..8df6c019f8a2 100644
>>> --- a/drivers/pci/endpoint/functions/pci-epf-test.c
>>> +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
>>> @@ -169,14 +169,12 @@ static int pci_epf_test_read(struct pci_epf_test *epf_test)
>>>  		goto err_addr;
>>>  	}
>>>  
>>> -	buf = kzalloc(reg->size, GFP_KERNEL);
>>> +	buf = kmemdup(src_addr, reg->size, GFP_KERNEL);
>>>  	if (!buf) {
>>>  		ret = -ENOMEM;
>>>  		goto err_map_addr;
>>>  	}
>>>  
>>> -	memcpy(buf, src_addr, reg->size);
>>> -
>>>  	crc32 = crc32_le(~0, buf, reg->size);
>>>  	if (crc32 != reg->checksum)
>>>  		ret = -EIO;
>>> -- 
>>> 2.19.1
>>>
Kishon Vijay Abraham I - Feb. 11, 2019, 12:37 p.m.
Hi Gustavo,

On 11/02/19 2:45 PM, Gustavo Pimentel wrote:
> On 11/02/2019 05:48, Kishon Vijay Abraham I wrote:
>> Hi Lorenzo,
>>
>> On 08/02/19 5:50 PM, Lorenzo Pieralisi wrote:
>>> On Thu, Dec 06, 2018 at 08:52:25PM +0800, Wen Yang wrote:
>>>> kmemdup has implemented the function that kmalloc() + memcpy().
>>>> We prefer to kmemdup rather than code opened implementation.
>>>>
>>>> This issue was detected with the help of coccinelle.
>>>>
>>>> Signed-off-by: Wen Yang <wen.yang99@zte.com.cn>
>>>> CC: Kishon Vijay Abraham I <kishon@ti.com>
>>>> CC: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
>>>> CC: Bjorn Helgaas <bhelgaas@google.com>
>>>> CC: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
>>>> CC: Niklas Cassel <niklas.cassel@axis.com>
>>>> CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>>>> CC: Cyrille Pitchen <cyrille.pitchen@free-electrons.com>
>>>> CC: linux-pci@vger.kernel.org (open list:PCI ENDPOINT SUBSYSTEM)
>>>> CC: linux-kernel@vger.kernel.org (open list)
>>>> ---
>>>>  drivers/pci/endpoint/functions/pci-epf-test.c | 4 +---
>>>>  1 file changed, 1 insertion(+), 3 deletions(-)
>>>
>>> Kishon,
>>>
>>> this looks OK to me, anything I am missing ?
>>
>> For the existing code this might seem the right thing to do but ideally the
>> memcpy here should be changed to memcpy_fromio/memcpy_toio.
>>
>> Also later when we plan to use DMA (on the endpoint) for data transfer, we have
>> to use kzalloc and dma_map_single APIs.
> 
> Are you considering to use the eDMA driver that I'm developing?

I used system DMA for my testing. But in the DesignWare driver, we should be
able to choose between system DMA or any other DMA based on the platforms
capabilities.

Thanks
Kishon

Patch

diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
index 3e86fa3c7da3..8df6c019f8a2 100644
--- a/drivers/pci/endpoint/functions/pci-epf-test.c
+++ b/drivers/pci/endpoint/functions/pci-epf-test.c
@@ -169,14 +169,12 @@  static int pci_epf_test_read(struct pci_epf_test *epf_test)
 		goto err_addr;
 	}
 
-	buf = kzalloc(reg->size, GFP_KERNEL);
+	buf = kmemdup(src_addr, reg->size, GFP_KERNEL);
 	if (!buf) {
 		ret = -ENOMEM;
 		goto err_map_addr;
 	}
 
-	memcpy(buf, src_addr, reg->size);
-
 	crc32 = crc32_le(~0, buf, reg->size);
 	if (crc32 != reg->checksum)
 		ret = -EIO;