Re: [PATCH v2] mmc: core: Use GFP_NOIO in ACMD22

[Adrian Hunter <adrian.hunter@intel.com>]

On 21/10/24 15:24, Avri Altman wrote:
>>
>> On 18/10/24 08:29, Avri Altman wrote:
>>> While reviewing the SDUC series, Adrian made a comment concerning the
>>> memory allocation code in mmc_sd_num_wr_blocks() - see [1].
>>> Prevent memory allocations from triggering I/O operations while ACMD22
>>> is in progress.
>>>
>>> [1] https://www.spinics.net/lists/linux-mmc/msg82199.html
>>>
>>> Suggested-by: Adrian Hunter <adrian.hunter@intel.com>
>>> Signed-off-by: Avri Altman <avri.altman@wdc.com>
>>> Cc: stable@vger.kernel.org
>>
>> Some checkpatch warnings:
>>
>>   WARNING: Use lore.kernel.org archive links when possible - see
>> https://lore.kernel.org/lists.html
>>   #12:
>>   [1] https://www.spinics.net/lists/linux-mmc/msg82199.html
> Done.
> 
>>
>>   WARNING: The commit message has 'stable@', perhaps it also needs a
>> 'Fixes:' tag?
> I tried to look for the patch that introduced mmc_sd_num_wr_blocks but couldn't find it in Ulf's tree.

Seems like the following introduced the kmalloc()

	commit 051913dada046ac948eb6f48c0717fc25de2a917
	Author: Ben Dooks <ben@simtec.co.uk>
	Date:   Mon Jun 8 23:33:57 2009 +0100

	    mmc_block: do not DMA to stack

> 
> Thanks,
> Avri
>>
>>   total: 0 errors, 2 warnings, 17 lines checked
>>
>> Otherwise:
>>
>> Reviewed-by: Adrian Hunter <adrian.hunter@intel.com>
>>
>>>
>>> ---
>>> Changes since v1:
>>>  - Move memalloc_noio_restore around (Adrian)
>>> ---
>>>  drivers/mmc/core/block.c | 4 ++++
>>>  1 file changed, 4 insertions(+)
>>>
>>> diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c index
>>> 04f3165cf9ae..a813fd7f39cc 100644
>>> --- a/drivers/mmc/core/block.c
>>> +++ b/drivers/mmc/core/block.c
>>> @@ -995,6 +995,8 @@ static int mmc_sd_num_wr_blocks(struct mmc_card
>> *card, u32 *written_blocks)
>>>       u32 result;
>>>       __be32 *blocks;
>>>       u8 resp_sz = mmc_card_ult_capacity(card) ? 8 : 4;
>>> +     unsigned int noio_flag;
>>> +
>>>       struct mmc_request mrq = {};
>>>       struct mmc_command cmd = {};
>>>       struct mmc_data data = {};
>>> @@ -1018,7 +1020,9 @@ static int mmc_sd_num_wr_blocks(struct
>> mmc_card *card, u32 *written_blocks)
>>>       mrq.cmd = &cmd;
>>>       mrq.data = &data;
>>>
>>> +     noio_flag = memalloc_noio_save();
>>>       blocks = kmalloc(resp_sz, GFP_KERNEL);
>>> +     memalloc_noio_restore(noio_flag);
>>>       if (!blocks)
>>>               return -ENOMEM;
>>>
>