Re: [PATCH 3/3] mmc: change .get_ro() callback semantics

From: Marc Pignat
Date: Tue Jun 03 2008 - 06:08:04 EST


Hi all!

On Friday 23 May 2008, Anton Vorontsov wrote:
> get_ro() callback must return values >= 0 for its logical state, and
...
> static void pxamci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
> diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
> index f2e9885..ef3b773 100644
> --- a/include/linux/mmc/host.h
> +++ b/include/linux/mmc/host.h
> @@ -55,6 +55,9 @@ struct mmc_host_ops {
> * Avoid calling these three functions too often or in a "fast path",
> * since underlaying controller might implement them in an expensive
> * and/or slow way.
> + *
> + * .get_ro and .get_cd should return >= 0 for their logical values,
> + * or negative errno value in case of error.
> */

I would suggest to use something more strict (bulletproof), something like:

/*
* get_ro will return:
* 0 for a read/write card
* 1 for a read-only card
* -ENOSYS when not supported
* or a negative errno when something bad happened
*
* get_cd will return:
* 0 for a absent card
* 1 for a present card
* -ENOSYS when not supported
* or a negative errno when something bad happened
*/

I think we have missed one important information: which context these callbacks
can rely on (hard_irq, soft_irq, ...).



Best regards

Marc

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