Messages in this thread | | | Date | Wed, 10 May 2017 10:24:25 +0200 | From | Ingo Molnar <> | Subject | Re: [RFC 09/10] x86/mm: Rework lazy TLB to track the actual loaded mm |
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* Thomas Gleixner <tglx@linutronix.de> wrote:
> On Wed, 10 May 2017, Ingo Molnar wrote: > > > > * Thomas Gleixner <tglx@linutronix.de> wrote: > > > > > On Sun, 7 May 2017, Andy Lutomirski wrote: > > > > /* context.lock is held for us, so we don't need any locking. */ > > > > static void flush_ldt(void *current_mm) > > > > { > > > > + struct mm_struct *mm = current_mm; > > > > mm_context_t *pc; > > > > > > > > - if (current->active_mm != current_mm) > > > > + if (this_cpu_read(cpu_tlbstate.loaded_mm) != current_mm) > > > > > > While functional correct, this really should compare against 'mm'. > > > > > > > return; > > > > > > > > - pc = ¤t->active_mm->context; > > > > + pc = &mm->context; > > > > So this appears to be the function: > > > > static void flush_ldt(void *current_mm) > > { > > struct mm_struct *mm = current_mm; > > mm_context_t *pc; > > > > if (this_cpu_read(cpu_tlbstate.loaded_mm) != current_mm) > > return; > > > > pc = &mm->context; > > set_ldt(pc->ldt->entries, pc->ldt->size); > > } > > > > why not rename 'current_mm' to 'mm' and remove the 'mm' local variable? > > Because you cannot dereference a void pointer, i.e. &mm->context ....
Indeed, doh! The naming totally confused me. The way I'd write it is the canonical form for such callbacks:
static void flush_ldt(void *data) { struct mm_struct *mm = data;
... which beyond unconfusing me would probably also have prevented any accidental use of the 'current_mm' callback argument.
Thanks,
Ingo
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