Re: [PATCH] mmc: add module parameter to set whether cards are assumed removable

[Adrian Hunter <adrian.hunter@xxxxxxxxx>]

Ben Hutchings wrote:
> Some people run general-purpose distribution kernels on netbooks with
> a card that is physically non-removable or logically non-removable
> (e.g. used for /home) and cannot be cleanly unmounted during suspend.
> Add a module parameter to set whether cards are assumed removable or
> non-removable, with the default set by CONFIG_MMC_UNSAFE_RESUME.
>
> Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
> ---

You do not cater for having more than one slot e.g. N900 has two:
one internal non-removable and one external that is removable.

What about a sysfs entry instead e.g.

/sys/class/mmc-host/mmc*/nonremovable



>  drivers/mmc/core/Kconfig |    4 +++-
>  drivers/mmc/core/core.c  |   16 ++++++++++++++++
>  drivers/mmc/core/core.h  |    2 ++
>  drivers/mmc/core/mmc.c   |   23 +----------------------
>  drivers/mmc/core/sd.c    |   21 +--------------------
>  5 files changed, 23 insertions(+), 43 deletions(-)
>
> diff --git a/drivers/mmc/core/Kconfig b/drivers/mmc/core/Kconfig
> index ab37a6d..bb22ffd 100644
> --- a/drivers/mmc/core/Kconfig
> +++ b/drivers/mmc/core/Kconfig
> @@ -3,7 +3,7 @@
>  #
>  
>  config MMC_UNSAFE_RESUME
> -	bool "Allow unsafe resume (DANGEROUS)"
> +	bool "Assume MMC/SD cards are non-removable (DANGEROUS)"
>  	help
>  	  If you say Y here, the MMC layer will assume that all cards
>  	  stayed in their respective slots during the suspend. The
> @@ -14,3 +14,5 @@ config MMC_UNSAFE_RESUME
>  	  This option is usually just for embedded systems which use
>  	  a MMC/SD card for rootfs. Most people should say N here.
>  
> +	  This option sets a default which can be overridden by the
> +	  module parameter "removable=0" or "removable=1".
> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
> index d98b0e2..010c964 100644
> --- a/drivers/mmc/core/core.c
> +++ b/drivers/mmc/core/core.c
> @@ -48,6 +48,22 @@ int use_spi_crc = 1;
>  module_param(use_spi_crc, bool, 0);
>  
>  /*
> + * We normally treat cards as removed during suspend if they are not
> + * known to be on a non-removable bus, to avoid the risk of writing
> + * back data to a different card after resume.  Allow this to be
> + * overridden if necessary.
> + */
> +#ifdef CONFIG_MMC_UNSAFE_RESUME
> +int mmc_assume_removable;
> +#else
> +int mmc_assume_removable = 1;
> +#endif
> +module_param_named(removable, mmc_assume_removable, bool, 0644);
> +MODULE_PARM_DESC(
> +	removable,
> +	"MMC/SD cards are removable and may be removed during suspend");
> +
> +/*
>   * Internal function. Schedule delayed work in the MMC work queue.
>   */
>  static int mmc_schedule_delayed_work(struct delayed_work *work,
> diff --git a/drivers/mmc/core/core.h b/drivers/mmc/core/core.h
> index 1c68783..d20b7bc 100644
> --- a/drivers/mmc/core/core.h
> +++ b/drivers/mmc/core/core.h
> @@ -64,7 +64,9 @@ int mmc_attach_mmc(struct mmc_host *host, u32 ocr);
>  int mmc_attach_sd(struct mmc_host *host, u32 ocr);
>  int mmc_attach_sdio(struct mmc_host *host, u32 ocr);
>  
> +/* Module parameters */
>  extern int use_spi_crc;
> +extern int mmc_assume_removable;
>  
>  /* Debugfs information for hosts and cards */
>  void mmc_add_host_debugfs(struct mmc_host *host);
> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
> index bfefce3..c111894 100644
> --- a/drivers/mmc/core/mmc.c
> +++ b/drivers/mmc/core/mmc.c
> @@ -602,25 +602,6 @@ static int mmc_awake(struct mmc_host *host)
>  	return err;
>  }
>  
> -#ifdef CONFIG_MMC_UNSAFE_RESUME
> -
> -static const struct mmc_bus_ops mmc_ops = {
> -	.awake = mmc_awake,
> -	.sleep = mmc_sleep,
> -	.remove = mmc_remove,
> -	.detect = mmc_detect,
> -	.suspend = mmc_suspend,
> -	.resume = mmc_resume,
> -	.power_restore = mmc_power_restore,
> -};
> -
> -static void mmc_attach_bus_ops(struct mmc_host *host)
> -{
> -	mmc_attach_bus(host, &mmc_ops);
> -}
> -
> -#else
> -
>  static const struct mmc_bus_ops mmc_ops = {
>  	.awake = mmc_awake,
>  	.sleep = mmc_sleep,
> @@ -645,15 +626,13 @@ static void mmc_attach_bus_ops(struct mmc_host *host)
>  {
>  	const struct mmc_bus_ops *bus_ops;
>  
> -	if (host->caps & MMC_CAP_NONREMOVABLE)
> +	if (host->caps & MMC_CAP_NONREMOVABLE || !mmc_assume_removable)
>  		bus_ops = &mmc_ops_unsafe;
>  	else
>  		bus_ops = &mmc_ops;
>  	mmc_attach_bus(host, bus_ops);
>  }
>  
> -#endif
> -
>  /*
>   * Starting point for MMC card init.
>   */
> diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
> index 10b2a4d..fdd414e 100644
> --- a/drivers/mmc/core/sd.c
> +++ b/drivers/mmc/core/sd.c
> @@ -606,23 +606,6 @@ static void mmc_sd_power_restore(struct mmc_host *host)
>  	mmc_release_host(host);
>  }
>  
> -#ifdef CONFIG_MMC_UNSAFE_RESUME
> -
> -static const struct mmc_bus_ops mmc_sd_ops = {
> -	.remove = mmc_sd_remove,
> -	.detect = mmc_sd_detect,
> -	.suspend = mmc_sd_suspend,
> -	.resume = mmc_sd_resume,
> -	.power_restore = mmc_sd_power_restore,
> -};
> -
> -static void mmc_sd_attach_bus_ops(struct mmc_host *host)
> -{
> -	mmc_attach_bus(host, &mmc_sd_ops);
> -}
> -
> -#else
> -
>  static const struct mmc_bus_ops mmc_sd_ops = {
>  	.remove = mmc_sd_remove,
>  	.detect = mmc_sd_detect,
> @@ -643,15 +626,13 @@ static void mmc_sd_attach_bus_ops(struct mmc_host *host)
>  {
>  	const struct mmc_bus_ops *bus_ops;
>  
> -	if (host->caps & MMC_CAP_NONREMOVABLE)
> +	if (host->caps & MMC_CAP_NONREMOVABLE || !mmc_assume_removable)
>  		bus_ops = &mmc_sd_ops_unsafe;
>  	else
>  		bus_ops = &mmc_sd_ops;
>  	mmc_attach_bus(host, bus_ops);
>  }
>  
> -#endif
> -
>  /*
>   * Starting point for SD card init.
>   */

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