Re: RFC: remove set_fs for m68k

Michael Schmitz
2021-08-15T19:17:25Z

Hi Christoph,

On 15/08/21 7:42 pm, Christoph Hellwig wrote:
> Hi Michael,
>
> after your last mail I went back and looked very closely at the
> set_fs removal and your debug patches below. And one hunk stands out:
>
>> static inline void flush_tlb_page(struct vm_area_struct *vma, unsigned long addr)
>> {
>> - if (vma->vm_mm == current->active_mm)
>> + if (vma->vm_mm == current->active_mm) {
>> + unsigned long old_fc = force_user_fc_begin();
>> __flush_tlb_one(addr);
>> + force_user_fc_end(old_fc);
>> + }
> This is the only old user of force_uaccess_begin, and the only one
> where this patch adds back a DFC/SFC access where there was none at
> at all with the set_fs removal. So I'd be curious if you just add this
> hunk (plus the supporting infrastructure) on top of my tree for now to
> see if there were some side effects of the instructions that were
> important, be that seralization, timing or anything else.

Would it be acceptable to add this on top of the
probe040/do_040writeback1 patch that I'm currently testing?

Cheers,

Michael