[...] >>>> +#if IS_ENABLED(CONFIG_MMC_BLOCK) >>> >>> What wrong with a regular ifdefs stubs? Why do you need IS_ENABLED()? >> >> This is because the entire block layer can be compiled as a >> module. > > The block layer cannot be a module, but the MMC layer can. > >> I'm all for making CONFIG_MMC_BLOCK into a bool... but >> don't know how people (Intel laptops) feel about that extra >> code in their kernel at all times. > > I think CONFIG_MMC should remain tristate. However, we could > consider making CONFIG_MMC_BLOCK a 'bool' symbol and > linking it into the mmc-core module when enabled. That is a good idea, no matter what. We should do the same thing for CONFIG_MMC_TEST. There are really no need to have to separate modules, one is more than enough. However, I don't think that by itself, solves the changed life-cycle issue of the card debugfs node. Some more protection is needed, to make sure the mmc block device is loaded/probed before calling mmc_blk_card_status_get(). > >>> It seems like the life cycle of the card debugfs node is now being >>> controlled as when the mmc block device driver has been successfully >>> probed. We need to deal with that somehow. >> >> Only for these two files but yes. >> >> ext_csd is a bit dubious as it is only available on storage devices >> (eMMC) that can not be SD, SDIO or combo cards, and we could make >> it only appear if using the block layer. >> >> The card status however we need to keep if people want it. >> >> We *COULD* consider just thrashing these debugfs files. It is not >> technically ABI and I wonder who is actually using them. > > I think the ext_csd is extremely useful on storage devices to have > exposed to user space in some form. There is a comment saying > that we don't store it in RAM at the moment as it is rarely used, > but we could change that, as it's only 512 bytes per eMMC device > and there is rarely more than one of them. IIRC, the ext_csd is > entirely readonly and doesn't change during runtime, so we > gain nothing by issuing the commands every time someone reads > the debugfs file. First, we have mmc utils (going via mmc ioctl), which purpose are exactly for these cases. As a matter of fact it does a better job, since it even present the data in a more human readable format. Second, ext csd gets updated very often to control/change some behavior of the device. You must be mixing this up with some of the other card registers. Kind regards Uffe
