On Thu, Jun 04, 2020 at 09:58:07AM +0200, Thomas Gleixner wrote:
> Kees Cook <keescook@xxxxxxxxxxxx> writes:
> > -#ifdef NODE_NOT_IN_PAGE_FLAGS
> > - pfn_align = node_map_pfn_alignment();
> > - if (pfn_align && pfn_align < PAGES_PER_SECTION) {
> > - printk(KERN_WARNING "Node alignment %LuMB < min %LuMB, rejecting NUMA config\n",
> > - PFN_PHYS(pfn_align) >> 20,
> > - PFN_PHYS(PAGES_PER_SECTION) >> 20);
> > - return -EINVAL;
> > + if (IS_ENABLED(NODE_NOT_IN_PAGE_FLAGS)) {
>
> Hrm, clever ...
>
> > + unsigned long pfn_align = node_map_pfn_alignment();
> > +
> > + if (pfn_align && pfn_align < PAGES_PER_SECTION) {
> > + pr_warn("Node alignment %LuMB < min %LuMB, rejecting NUMA config\n",
> > + PFN_PHYS(pfn_align) >> 20,
> > + PFN_PHYS(PAGES_PER_SECTION) >> 20);
> > + return -EINVAL;
> > + }
> > }
> > -#endif
> > if (!numa_meminfo_cover_memory(mi))
> > return -EINVAL;
> >
> > diff --git a/include/linux/page-flags-layout.h b/include/linux/page-flags-layout.h
> > index 71283739ffd2..1a4cdec2bd29 100644
> > --- a/include/linux/page-flags-layout.h
> > +++ b/include/linux/page-flags-layout.h
> > @@ -100,7 +100,7 @@
> > * there. This includes the case where there is no node, so it is implicit.
> > */
> > #if !(NODES_WIDTH > 0 || NODES_SHIFT == 0)
> > -#define NODE_NOT_IN_PAGE_FLAGS
> > +#define NODE_NOT_IN_PAGE_FLAGS 1
>
> but if we ever lose the 1 then the above will silently compile the code
> within the IS_ENABLED() section out.
That's true, yes. I considered two other ways to do this:
1) smallest patch, but more #ifdef:
diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
index 59ba008504dc..fbf5231a3d35 100644
--- a/arch/x86/mm/numa.c
+++ b/arch/x86/mm/numa.c
@@ -541,7 +541,9 @@ static void __init numa_clear_kernel_node_hotplug(void)
static int __init numa_register_memblks(struct numa_meminfo *mi)
{
- unsigned long uninitialized_var(pfn_align);
+#ifdef NODE_NOT_IN_PAGE_FLAGS
+ unsigned long pfn_align;
+#endif
int i, nid;
/* Account for nodes with cpus and no memory */
2) medium size, weird style:
diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
index 59ba008504dc..0df7ba9b21b2 100644
--- a/arch/x86/mm/numa.c
+++ b/arch/x86/mm/numa.c
@@ -541,7 +541,6 @@ static void __init numa_clear_kernel_node_hotplug(void)
static int __init numa_register_memblks(struct numa_meminfo *mi)
{
- unsigned long uninitialized_var(pfn_align);
int i, nid;
/* Account for nodes with cpus and no memory */
@@ -570,12 +569,15 @@ static int __init numa_register_memblks(struct numa_meminfo *mi)
* whether its granularity is fine enough.
*/
#ifdef NODE_NOT_IN_PAGE_FLAGS
- pfn_align = node_map_pfn_alignment();
- if (pfn_align && pfn_align < PAGES_PER_SECTION) {
- printk(KERN_WARNING "Node alignment %LuMB < min %LuMB, rejecting NUMA config\n",
- PFN_PHYS(pfn_align) >> 20,
- PFN_PHYS(PAGES_PER_SECTION) >> 20);
- return -EINVAL;
+ {
+ unsigned long pfn_align = node_map_pfn_alignment();
+
+ if (pfn_align && pfn_align < PAGES_PER_SECTION) {
+ pr_warn("Node alignment %LuMB < min %LuMB, rejecting NUMA config\n",
+ PFN_PHYS(pfn_align) >> 20,
+ PFN_PHYS(PAGES_PER_SECTION) >> 20);
+ return -EINVAL;
+ }
}
#endif
if (!numa_meminfo_cover_memory(mi))
and 3 is what I sent: biggest, but removes #ifdef
Any preference?
Thanks!
--
Kees Cook
