Messages in this thread | | | Subject | Re: [PATCH] x86/xen: Remove use of VLAs | From | Laura Abbott <> | Date | Tue, 17 Apr 2018 16:33:57 -0700 |
| |
On 04/17/2018 12:16 AM, Juergen Gross wrote: > On 16/04/18 15:27, Boris Ostrovsky wrote: >> On 04/13/2018 06:11 PM, Laura Abbott wrote: >>> There's an ongoing effort to remove VLAs[1] from the kernel to eventually >>> turn on -Wvla. The few VLAs in use have an upper bound based on a size >>> of 64K. This doesn't produce an excessively large stack so just switch >>> the upper bound. >>> >>> [1] https://lkml.org/lkml/2018/3/7/621 >>> >>> Signed-off-by: Laura Abbott <labbott@redhat.com> >>> --- >>> arch/x86/xen/enlighten_pv.c | 6 ++---- >>> 1 file changed, 2 insertions(+), 4 deletions(-) >>> >>> diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c >>> index c36d23aa6c35..d96a5a535cbb 100644 >>> --- a/arch/x86/xen/enlighten_pv.c >>> +++ b/arch/x86/xen/enlighten_pv.c >>> @@ -421,8 +421,7 @@ static void xen_load_gdt(const struct desc_ptr *dtr) >>> { >>> unsigned long va = dtr->address; >>> unsigned int size = dtr->size + 1; >>> - unsigned pages = DIV_ROUND_UP(size, PAGE_SIZE); >> >> >> >> Isn't dtr->size always either GDT_SIZE or 0? > > GDT_SIZE - 1 :-) > >>> - unsigned long frames[pages]; >>> + unsigned long frames[DIV_ROUND_UP(SZ_64K, PAGE_SIZE)]; > > So we could just go with one frame and modify the BUG_ON() further below > accordingly. >
Do you want to just remove the loop as well since we're never going to do more than one frame? We end up with net code deletion.
Thanks, Laura
> > Juergen >
| |