Re: [PATCH 1/2] Revert "mmc: core: wait while adding MMC host to ensure root mounts successfully"

Sergey Yanovich
2013-04-04T13:52:46Z

On Thu, 2013-04-04 at 16:41 +0300, Adrian Hunter wrote:
> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
> index ad7decc..3bf1c46 100644
> --- a/drivers/mmc/core/core.c
> +++ b/drivers/mmc/core/core.c
> @@ -2418,7 +2418,6 @@ void mmc_start_host(struct mmc_host *host)
> host->rescan_disable = 0;
> mmc_power_up(host);
> mmc_detect_change(host, 0);
> - mmc_flush_scheduled_work();
> }
>
> void mmc_stop_host(struct mmc_host *host)

Without some kind of synchronization between end of card probing and
start of root mounting, it is not safe to have root on an mmc card.

In other words, 'root_wait' will be mandatory to ensure successful mount
of root filesystem on an mmc card. It may be worth documenting
somewhere.

It is not a big deal. I could live with a patched kernel or pass the
parameter in the systems I work with. However, other people will fall in
this trap later, and it would be nice to let them know what to do.