geom: create disk_free() to free uninitialized disks

[imp]

Summary

disk_destroy() only works on disks that have proceeded through
disk_create(). Creating disks is a multi-step process. There are times
that we may need to free nascent disks that have been allocated, but not
created. disk_free() will free the memory allocated with disk_alloc()
when the creation of the disk needs to be aborted before it can proceed
to disk_create() for whatever reason.

[rpokala]

sys/geom/geom_disk.c

837

I would call disk_free(dp) here, to benefit from the KASSERT()s, and to make it abundantly clear that disk_free() is always the final destination of memory from disk_alloc().

[imp]

ravi's comments

[imp]

On second thought, I'm going to abandon this approach and schedule the cam register routine into a taskqueue so we can sleep. There's no good retry mechanism here, and adding one would make things more complicated. We can switch to waiting for memory to have a more robust system with simpler code. This also matches at least some of the feedback I've received privately (thanks Chuck). I'll post that review when I have it done.

sys/geom/geom_disk.c

837

Not a bad idea... I'll shuffle and regen.