Re: [PATCH] mmc: change to use kmalloc

[yalin wang]

> On Nov 12, 2015, at 05:57, Andy Shevchenko  wrote:
> 
> On Wed, Nov 11, 2015 at 11:17 PM, Peter Hurley  
> wrote:
>> On 11/11/2015 12:02 PM, Alim Akhtar wrote:
>>> Hi Yalin,
>>> 
>>> On Wed, Nov 11, 2015 at 9:53 AM, yalin wang  
>>> wrote:
 Use kmalloc instead of kzalloc, zero the memory is not needed.
 
>>> why you want to do this? what problem you faces, and how this resolves the 
>>> same?
>> 
>> The patch fixes an inefficiency: explicitly zeroing memory that is then
>> immediately overwritten 6 lines below is wasteful.
> 
> It might fix previous kzalloc as well, though better not to do since
> it's error prone.
> 
yeah,  i will send a new patch ,



>> 
>> Regards,
>> Peter Hurley
>> 
 Signed-off-by: yalin wang 
 ---
 drivers/mmc/card/block.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
 
 diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
 index 23b6c8e..975cd3e 100644
 --- a/drivers/mmc/card/block.c
 +++ b/drivers/mmc/card/block.c
 @@ -365,7 +365,7 @@ static struct mmc_blk_ioc_data 
 *mmc_blk_ioctl_copy_from_user(
if (!idata->buf_bytes)
return idata;
 
 -   idata->buf = kzalloc(idata->buf_bytes, GFP_KERNEL);
 +   idata->buf = kmalloc(idata->buf_bytes, GFP_KERNEL);
if (!idata->buf) {
err = -ENOMEM;
goto idata_err;
 --
 1.9.1
>> 
>> --
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>> Please read the FAQ at  http://www.tux.org/lkml/
> 
> 
> 
> -- 
> With Best Regards,
> Andy Shevchenko

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Re: [PATCH] mmc: change to use kmalloc

[Alim Akhtar]

Hi Yalin,

On Wed, Nov 11, 2015 at 9:53 AM, yalin wang  wrote:
> Use kmalloc instead of kzalloc, zero the memory is not needed.
>
why you want to do this? what problem you faces, and how this resolves the same?

> Signed-off-by: yalin wang 
> ---
>  drivers/mmc/card/block.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
> index 23b6c8e..975cd3e 100644
> --- a/drivers/mmc/card/block.c
> +++ b/drivers/mmc/card/block.c
> @@ -365,7 +365,7 @@ static struct mmc_blk_ioc_data 
> *mmc_blk_ioctl_copy_from_user(
> if (!idata->buf_bytes)
> return idata;
>
> -   idata->buf = kzalloc(idata->buf_bytes, GFP_KERNEL);
> +   idata->buf = kmalloc(idata->buf_bytes, GFP_KERNEL);
> if (!idata->buf) {
> err = -ENOMEM;
> goto idata_err;
> --
> 1.9.1
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
> the body of a message to majord...@vger.kernel.org
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-- 
Regards,
Alim
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Re: [PATCH] mmc: change to use kmalloc

[Peter Hurley]

On 11/11/2015 12:02 PM, Alim Akhtar wrote:
> Hi Yalin,
> 
> On Wed, Nov 11, 2015 at 9:53 AM, yalin wang  wrote:
>> Use kmalloc instead of kzalloc, zero the memory is not needed.
>>
> why you want to do this? what problem you faces, and how this resolves the 
> same?

The patch fixes an inefficiency: explicitly zeroing memory that is then
immediately overwritten 6 lines below is wasteful.

Regards,
Peter Hurley

>> Signed-off-by: yalin wang 
>> ---
>>  drivers/mmc/card/block.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
>> index 23b6c8e..975cd3e 100644
>> --- a/drivers/mmc/card/block.c
>> +++ b/drivers/mmc/card/block.c
>> @@ -365,7 +365,7 @@ static struct mmc_blk_ioc_data 
>> *mmc_blk_ioctl_copy_from_user(
>> if (!idata->buf_bytes)
>> return idata;
>>
>> -   idata->buf = kzalloc(idata->buf_bytes, GFP_KERNEL);
>> +   idata->buf = kmalloc(idata->buf_bytes, GFP_KERNEL);
>> if (!idata->buf) {
>> err = -ENOMEM;
>> goto idata_err;
>> --
>> 1.9.1

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Re: [PATCH] mmc: change to use kmalloc

[Andy Shevchenko]

On Wed, Nov 11, 2015 at 11:17 PM, Peter Hurley  wrote:
> On 11/11/2015 12:02 PM, Alim Akhtar wrote:
>> Hi Yalin,
>>
>> On Wed, Nov 11, 2015 at 9:53 AM, yalin wang  wrote:
>>> Use kmalloc instead of kzalloc, zero the memory is not needed.
>>>
>> why you want to do this? what problem you faces, and how this resolves the 
>> same?
>
> The patch fixes an inefficiency: explicitly zeroing memory that is then
> immediately overwritten 6 lines below is wasteful.

It might fix previous kzalloc as well, though better not to do since
it's error prone.

>
> Regards,
> Peter Hurley
>
>>> Signed-off-by: yalin wang 
>>> ---
>>>  drivers/mmc/card/block.c | 2 +-
>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
>>> index 23b6c8e..975cd3e 100644
>>> --- a/drivers/mmc/card/block.c
>>> +++ b/drivers/mmc/card/block.c
>>> @@ -365,7 +365,7 @@ static struct mmc_blk_ioc_data 
>>> *mmc_blk_ioctl_copy_from_user(
>>> if (!idata->buf_bytes)
>>> return idata;
>>>
>>> -   idata->buf = kzalloc(idata->buf_bytes, GFP_KERNEL);
>>> +   idata->buf = kmalloc(idata->buf_bytes, GFP_KERNEL);
>>> if (!idata->buf) {
>>> err = -ENOMEM;
>>> goto idata_err;
>>> --
>>> 1.9.1
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majord...@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/



-- 
With Best Regards,
Andy Shevchenko
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