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

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

On 09/11/11 06:31, Sujit Reddy Thumma wrote:
> Kill block requests when the host knows that the card is
> removed from the slot and is sure that subsequent requests
> are bound to fail. Do this silently so that the block
> layer doesn't output unnecessary error messages.
> 
> This patch implements suggestion from Adrian Hunter,
> http://thread.gmane.org/gmane.linux.kernel.mmc/2714/focus=3474
> 
> Signed-off-by: Sujit Reddy Thumma <sthumma@codeaurora.org>
> ---


It is safer to have zero initialisations so I suggest inverting
the meaning of the state bit i.e.

#define MMC_STATE_CARD_GONE	(1<<7)		/* card removed from the slot */


Also it would be nice is a request did not start if the card is
gone.  For the non-async case, that is easy:

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 5278ffb..91d7721 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -259,7 +259,7 @@ static void mmc_wait_for_req_done(struct mmc_host *host,
                wait_for_completion(&mrq->completion);

                cmd = mrq->cmd;
-               if (!cmd->error || !cmd->retries)
+               if (!cmd->error || !cmd->retries || mmc_card_gone(host->card))
                        break;

                pr_debug("%s: req failed (CMD%u): %d, retrying...\n",
@@ -374,6 +374,10 @@ EXPORT_SYMBOL(mmc_start_req);
  */
 void mmc_wait_for_req(struct mmc_host *host, struct mmc_request *mrq)
 {
+       if (mmc_card_gone(host->card)) {
+               mrq->cmd->error = -ENODEV;
+               return;
+       }
        __mmc_start_req(host, mrq);
        mmc_wait_for_req_done(host, mrq);
 }



The async case is harder...


>  drivers/mmc/card/queue.c |    5 +++++
>  drivers/mmc/core/bus.c   |    2 ++
>  include/linux/mmc/card.h |    3 +++
>  3 files changed, 10 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/mmc/card/queue.c b/drivers/mmc/card/queue.c
> index dcad59c..f8a3298 100644
> --- a/drivers/mmc/card/queue.c
> +++ b/drivers/mmc/card/queue.c
> @@ -29,6 +29,8 @@
>   */
>  static int mmc_prep_request(struct request_queue *q, struct request *req)
>  {
> +	struct mmc_queue *mq = q->queuedata;
> +
>  	/*
>  	 * We only like normal block requests and discards.
>  	 */
> @@ -37,6 +39,9 @@ static int mmc_prep_request(struct request_queue *q, struct request *req)
>  		return BLKPREP_KILL;
>  	}
>  
> +	if (mq && mq->card && !mmc_card_inserted(mq->card))
> +		return BLKPREP_KILL;
> +
>  	req->cmd_flags |= REQ_DONTPREP;
>  
>  	return BLKPREP_OK;
> diff --git a/drivers/mmc/core/bus.c b/drivers/mmc/core/bus.c
> index 46b6e84..ea3be5d 100644
> --- a/drivers/mmc/core/bus.c
> +++ b/drivers/mmc/core/bus.c
> @@ -308,6 +308,7 @@ int mmc_add_card(struct mmc_card *card)
>  			mmc_card_ddr_mode(card) ? "DDR " : "",
>  			type, card->rca);
>  	}
> +	mmc_card_set_inserted(card);
>  
>  #ifdef CONFIG_DEBUG_FS
>  	mmc_add_card_debugfs(card);
> @@ -340,6 +341,7 @@ void mmc_remove_card(struct mmc_card *card)
>  			pr_info("%s: card %04x removed\n",
>  				mmc_hostname(card->host), card->rca);
>  		}
> +		card->state &= ~MMC_STATE_INSERTED;
>  		device_del(&card->dev);
>  	}
>  
> diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
> index b7a8cb1..be4125a 100644
> --- a/include/linux/mmc/card.h
> +++ b/include/linux/mmc/card.h
> @@ -209,6 +209,7 @@ 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 */
> @@ -362,6 +363,7 @@ 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)
> @@ -370,6 +372,7 @@ 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)