• Providing fine-grained malloc statistic by replacing M_DEVBUF with module-specific malloc types. These should help us to pinpoint the possible memory leakage in the future.
• Implementing xpt_alloc_ccb_nowait() and replacing all malloc/free based CCB memory management with xpt_alloc_ccb[_nowait]/xpt_free_ccb. Hopefully this would be helpful if someday we move the CCB allocator to use UMA instead of malloc().

Encouraged by: jeffr, rwatson
Reviewed by: gibbs, scottl
Approved by: re (scottl)