sys/cam/mmc/mmc_da.c: Refactor error handling

[kibab]

Summary

There is some code duplication in error handling paths in a few functions.
Create a function for printing such errors in human-readable way and get rid
of duplicates.

[imp]

make sure all the places you've put the mmc_handle_reply can handle errno-type errors. There's at least one that can't.

sys/cam/mmc/mmc_da.c

241

I'd consider making this a kassert.

823–824

My brain tells me you still need to check the error here, but reading code suggests we always set the ccb_h.status, so maybe that's OK.

side note: cam_periph_runccb should grow stats support for MMC_IO transactions.

826

so mmc_handle_reply returns ERRNO type errors. but two lines below, you return MMC_ERR_FAILED. You can't mix and match like that.

[kibab]

Sync Arcanist

[kibab]

sys/cam/mmc/mmc_da.c

823–824

Opened https://github.com/kibab/freebsd/issues/13 for stats part.

[kibab]

addressed reviewer comments

[bz]

sys/cam/mmc/mmc_da.c

241–243

I'd (a) line-wrap this at 80, (b) print func_code and possibly the ccb %p in the KASSERT; it makes debugging a lot easier if you hit it.

[kibab]

Address comments from bz@