Re: [RFC/PATCH] mmc: core: Kill block requests if card is removed

[Sujit Reddy Thumma <sthumma@codeaurora.org>]

On 10/12/2011 4:04 PM, Pavan Kondeti wrote:
> Hello Sujit,
>
> On 10/12/2011 1:06 PM, Sujit Reddy Thumma wrote:
>> Kill block requests when the host knows that the card is
>> removed from the slot and is sure that it can no longer
>> accept any requests.
>>
>> Kill this silently so that the block layer don't output
>> error messages unnecessarily.
>>
>> Signed-off-by: Sujit Reddy Thumma<sthumma@codeaurora.org>
>>
> <snip>
>>
>> diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
>> index 0ea4a06..7cdbc14 100644
>> --- a/include/linux/mmc/card.h
>> +++ b/include/linux/mmc/card.h
>> @@ -196,6 +196,7 @@ struct mmc_card {
>>   #define MMC_STATE_HIGHSPEED_DDR (1<<4)		/* card is in high speed mode */
>>   #define MMC_STATE_ULTRAHIGHSPEED (1<<5)		/* card is in ultra high speed mode */
>>   #define MMC_CARD_SDXC		(1<<6)		/* card is SDXC */
>> +#define MMC_STATE_INSERTED      (1<<7)          /* card present in the slot */
>>   	unsigned int		quirks; 	/* card quirks */
>>   #define MMC_QUIRK_LENIENT_FN0	(1<<0)		/* allow SDIO FN0 writes outside of the VS CCCR range */
>>   #define MMC_QUIRK_BLKSZ_FOR_BYTE_MODE (1<<1)	/* use func->cur_blksize */
>> @@ -344,6 +345,7 @@ static inline void __maybe_unused remove_quirk(struct mmc_card *card, int data)
>>   #define mmc_card_sdio(c)	((c)->type == MMC_TYPE_SDIO)
>>
>>   #define mmc_card_present(c)	((c)->state&  MMC_STATE_PRESENT)
>> +#define mmc_card_inserted(c)     ((c)->state&  MMC_STATE_INSERTED)
>>   #define mmc_card_readonly(c)	((c)->state&  MMC_STATE_READONLY)
>>   #define mmc_card_highspeed(c)	((c)->state&  MMC_STATE_HIGHSPEED)
>>   #define mmc_card_blockaddr(c)	((c)->state&  MMC_STATE_BLOCKADDR)
>> @@ -352,6 +354,7 @@ static inline void __maybe_unused remove_quirk(struct mmc_card *card, int data)
>>   #define mmc_card_ext_capacity(c) ((c)->state&  MMC_CARD_SDXC)
>>
>>   #define mmc_card_set_present(c)	((c)->state |= MMC_STATE_PRESENT)
>> +#define mmc_card_set_inserted(c) ((c)->state |= MMC_STATE_INSERTED)
>>   #define mmc_card_set_readonly(c) ((c)->state |= MMC_STATE_READONLY)
>>   #define mmc_card_set_highspeed(c) ((c)->state |= MMC_STATE_HIGHSPEED)
>>   #define mmc_card_set_blockaddr(c) ((c)->state |= MMC_STATE_BLOCKADDR)
>
> Why do we need another flag to indicate card's presence? can not we use
> MMC_STATE_PRESENT flag? This flag is set in mmc_add_card(). But not
> cleared any where...
>
MMC_STATE_PRESENT signifies the card presence in sysfs i.e. after 
device_add() is called we can be sure that kobject for card device is 
created. This will be cleared automatically when we do 
mmc_release_card() after card removal. But before this when doing 
device_del() is called the FS layer flush/sync the dirty data onto card. 
This creates unnecessary noise in dmesg log when the card is removed 
from the slot (without unmounting).
> Thanks,
> Pavan
>
>
Thanks,
Sujit