On Fri, Nov 13, 2020 at 12:04:23PM -0300, Martin Pieuchot wrote:
> Another simple refactoring of uvm_fault() removing a goto, ok?
I like it, ok jmatthew@
>
> Index: uvm/uvm_fault.c
> ===================================================================
> RCS file: /cvs/src/sys/uvm/uvm_fault.c,v
> retrieving revision 1.106
> diff -u -p -r1.106 uvm_fault.c
> --- uvm/uvm_fault.c 13 Nov 2020 14:18:25 -0000 1.106
> +++ uvm/uvm_fault.c 13 Nov 2020 15:01:41 -0000
> @@ -942,12 +942,24 @@ ReFault:
> return error;
> }
>
> - amap = ufi.entry->aref.ar_amap;
> - uobj = ufi.entry->object.uvm_obj;
> -
> /* (shadowed == TRUE) if there is an anon at the faulting address */
> shadowed = uvm_fault_upper_lookup(&ufi, &flt, anons, pages);
>
> + /* handle case 1: fault on an anon in our amap */
> + if (shadowed == TRUE) {
> + error = uvm_fault_upper(&ufi, &flt, anons, fault_type,
> + access_type);
> + switch (error) {
> + case ERESTART:
> + goto ReFault;
> + default:
> + return error;
> + }
> + }
> +
> + amap = ufi.entry->aref.ar_amap;
> + uobj = ufi.entry->object.uvm_obj;
> +
> /*
> * if the desired page is not shadowed by the amap and we have a
> * backing object, then we check to see if the backing object would
> @@ -1055,30 +1067,12 @@ ReFault:
> /*
> * note that at this point we are done with any front or back pages.
> * we are now going to focus on the center page (i.e. the one we've
> - * faulted on). if we have faulted on the top (anon) layer
> - * [i.e. case 1], then the anon we want is anons[centeridx] (we have
> - * not touched it yet). if we have faulted on the bottom (uobj)
> + * faulted on). if we have faulted on the bottom (uobj)
> * layer [i.e. case 2] and the page was both present and available,
> * then we've got a pointer to it as "uobjpage" and we've already
> * made it BUSY.
> */
> - /*
> - * there are four possible cases we must address: 1A, 1B, 2A, and 2B
> - */
> - /* redirect case 2: if we are not shadowed, go to case 2. */
> - if (shadowed == FALSE)
> - goto Case2;
> -
> - /* handle case 1: fault on an anon in our amap */
> - error = uvm_fault_upper(&ufi, &flt, anons, fault_type, access_type);
> - switch (error) {
> - case ERESTART:
> - goto ReFault;
> - default:
> - return error;
> - }
>
> -Case2:
> /* handle case 2: faulting on backing object or zero fill */
> /*
> * note that uobjpage can not be PGO_DONTCARE at this point. we now
>
