Re: CVS commit: src/sys

[Masao Uebayashi <uebayasi%tombi.co.jp@localhost>]

On Thu, Mar 25, 2010 at 04:57:27AM +0000, David Holland wrote:
> Well... yes, but I guess I don't understand how the read() in the PR
> would end up trapping in copyin/copyout. Presumably there's a uiomove
> in there somewhere, but I would have thought it wouldn't reach it at
> all if the I/O failed.
> 
> I suppose I ought to wade through genfs_getpages in more detail
> sometime...

        ubc_alloc()
          ubc_uiomove()
            uiomove()
              copyout_vmspace()
                copyout()
                  *trap*
        uvm_fault_internal()
          uvm_fault_lower()
            uvm_fault_lower_io()
              (... I/O ...)
                *fail*

(We need nice pictures to show UBC behavior.)

Masao

-- 
Masao Uebayashi / Tombi Inc. / Tel: +81-90-9141-4635