Re: [Xen-devel] [PATCH] xen: lift hypercall_cancel_continuation to sched.h

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 14.08.17 at 17:46, <wei.liu2@xxxxxxxxxx> wrote:
> --- a/xen/arch/x86/x86_64/compat/mm.c
> +++ b/xen/arch/x86/x86_64/compat/mm.c
> @@ -53,6 +53,7 @@ int compat_arch_memory_op(unsigned long cmd, 
> XEN_GUEST_HANDLE_PARAM(void) arg)
>      compat_pfn_t mfn;
>      unsigned int i;
>      int rc = 0;
> +    struct vcpu *curr = current;
>  
>      switch ( cmd )
>      {
> @@ -124,7 +125,7 @@ int compat_arch_memory_op(unsigned long cmd, 
> XEN_GUEST_HANDLE_PARAM(void) arg)
>          if ( __copy_to_guest(arg, &cmp, 1) )
>          {
>              if ( rc == __HYPERVISOR_memory_op )
> -                hypercall_cancel_continuation();
> +                hypercall_cancel_continuation(curr);
>              rc = -EFAULT;
>          }
>  
> @@ -133,7 +134,7 @@ int compat_arch_memory_op(unsigned long cmd, 
> XEN_GUEST_HANDLE_PARAM(void) arg)
>  
>      case XENMEM_machphys_mapping:
>      {
> -        struct domain *d = current->domain;
> +        struct domain *d = curr->domain;
>          struct compat_machphys_mapping mapping = {
>              .v_start = MACH2PHYS_COMPAT_VIRT_START(d),
>              .v_end   = MACH2PHYS_COMPAT_VIRT_END,

I don't think the local variable is really useful here - it's two
entirely distinct and uncommon paths which need it, yet
you calculate unconditionally now. With the variable
dropped
Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>

Jan


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