stand: shuffle dv_open/dv_init bits around

[kevans]

Summary

This is an attempt to only allow opening on devices that have actually successfully init (or have no dv_init?) -- wrap devsw->dv_open so we can kick back ENXIO consistently if we haven't been initialized successfully.

dv_open previously used varargs, but always took exactly one devdesc-esque pointer. Formalize the prototype as taking a struct devdesc *, we'll just use type-punning as needed and is safe in individual dv_open.

Some redundancy of walking through global devsw and initializing has been removed in favor of providing a common method for this in libsa. U-Boot uses it, though it did something slightly different: dv_init == NULL implied an unusable device, but this is now fine (and likely sufficiently edge-casey that it doesn't really matter).

[imp]

stand/common/dev_net.c

117–118

delete this line

stand/efi/libefi/efihttp.c

243

picking one at random... why this test?

stand/libsa/conf.c

45 ↗

(On Diff #59070)

I'd do (dev->dv_init() == 0) here.

58 ↗

(On Diff #59070)

Maybe add:

if (dev == NULL)
return (EINVAL);

stand/powerpc/kboot/hostdisk.c

90

Can we put the desc check only in the dv_open() function call you've added, then we know for sure it's != NULL, then we can remove the checks in all the functions.

stand/powerpc/ofw/main.c

127

I like this, but this change feels like a separate commit, if you're ok with splitting this a little...

[tsoome]

stand/libsa/conf.c

58 ↗

(On Diff #59070)

+1

[kevans]

Address review comments:

• Delete stale comment
• Push dev == null check into dv_open wrapper

Many of these were casting it to a disk_devdesc but only really needed the devdesc bits, so I killed off the local disk_devdesc and casted it as appropriate when passing elsewhere...

I'll commit it in these two pieces (in order):
https://github.com/kevans91/freebsd/commit/f2be8295bbb803b1c00bfa1cb78454a176ed7eef
https://github.com/kevans91/freebsd/commit/fcafa5bbaca2bac2749c577355c0418d16f96062

The review wasn't shaped like that since the dv_open wrapper started only being useful because of the dv_inited bits, but no qualms with splitting it now.

[tsoome]

stand/libsa/Makefile

148

the conf.c does sound a bit confusing. maybe devsw.c or devsw_utils.c or like?

[tsoome]

stand/libsa/stand.h

159

I think, either use bool, or if to keep int, then name it like dv_flags or dv_state and add constant values like above for dv_type.

[imp]

stand/i386/libfirewire/firewire.c

180–181

while you're here and changing it anyway... just delete this whole #if 0.

stand/libsa/Makefile

148

Good suggestion! I'd prefer devsw.c because we may need/want other wrappers.

stand/libsa/stand.h

159

It would be more in keeping with the rest of the system to call it dv_flags and a DV_FLAG_INIT_DONE or similar.
But dv_inited should be a bool.

[kevans]

conf.c -> devsw.c
dv_inited -> dv_flags (I liked DV_FLAG_INIT_DONE)