From: Kees Cook <keescook@chromium.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org,
Linus Torvalds <torvalds@linux-foundation.org>,
Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>,
Alexander Potapenko <glider@google.com>,
Joe Perches <joe@perches.com>, Andy Whitcroft <apw@canonical.com>,
x86@kernel.org, drbd-dev@lists.linbit.com,
linux-block@vger.kernel.org, b43-dev@lists.infradead.org,
netdev@vger.kernel.org, linux-wireless@vger.kernel.org,
linux-ide@vger.kernel.org, linux-clk@vger.kernel.org,
linux-spi@vger.kernel.org, linux-mm@kvack.org,
clang-built-linux@googlegroups.com
Subject: Re: [PATCH 01/10] x86/mm/numa: Remove uninitialized_var() usage
Date: Thu, 4 Jun 2020 07:34:54 -0700 [thread overview]
Message-ID: <202006040728.8797FAA4@keescook> (raw)
In-Reply-To: <874krr8dps.fsf@nanos.tec.linutronix.de>
On Thu, Jun 04, 2020 at 09:58:07AM +0200, Thomas Gleixner wrote:
> Kees Cook <keescook@chromium.org> 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
next prev parent reply other threads:[~2020-06-04 14:34 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-03 23:31 [PATCH 00/10] Remove uninitialized_var() macro Kees Cook
2020-06-03 23:31 ` [PATCH 01/10] x86/mm/numa: Remove uninitialized_var() usage Kees Cook
2020-06-04 7:58 ` Thomas Gleixner
2020-06-04 11:41 ` Miguel Ojeda
2020-06-04 14:56 ` Kees Cook
2020-06-04 15:22 ` Miguel Ojeda
2020-06-04 14:34 ` Kees Cook [this message]
2020-06-04 21:39 ` Thomas Gleixner
2020-06-04 22:39 ` Kees Cook
2020-06-03 23:31 ` [PATCH 02/10] drbd: " Kees Cook
2020-06-04 19:56 ` Nick Desaulniers
2020-06-03 23:31 ` [PATCH 03/10] b43: " Kees Cook
2020-06-04 20:08 ` Nick Desaulniers
2020-06-04 20:18 ` Kees Cook
2020-06-04 20:25 ` Nick Desaulniers
2020-06-05 9:20 ` Kalle Valo
2020-06-03 23:31 ` [PATCH 04/10] rtlwifi: rtl8192cu: " Kees Cook
2020-06-04 20:16 ` Nick Desaulniers
2020-06-05 9:18 ` Kalle Valo
2020-06-03 23:31 ` [PATCH 05/10] ide: " Kees Cook
2020-06-04 19:29 ` Nick Desaulniers
2020-06-04 20:20 ` Kees Cook
2020-06-04 20:29 ` Nick Desaulniers
2020-06-15 19:32 ` Kees Cook
2020-06-04 20:58 ` Sedat Dilek
2020-06-03 23:31 ` [PATCH 06/10] clk: st: " Kees Cook
2020-06-04 4:38 ` Stephen Boyd
2020-06-03 23:32 ` [PATCH 07/10] spi: davinci: " Kees Cook
2020-06-04 19:40 ` Nick Desaulniers
2020-06-03 23:32 ` [PATCH 08/10] checkpatch: Remove awareness of uninitialized_var() macro Kees Cook
2020-06-04 0:02 ` Joe Perches
2020-06-04 1:40 ` Kees Cook
2020-06-04 1:47 ` Joe Perches
2020-06-04 2:44 ` Kees Cook
2020-06-04 2:53 ` Sedat Dilek
2020-06-04 3:46 ` Kees Cook
2020-06-03 23:32 ` [PATCH 09/10] treewide: Remove uninitialized_var() usage Kees Cook
2020-06-04 3:33 ` Nathan Chancellor
2020-06-04 4:02 ` Kees Cook
2020-06-04 10:45 ` Leon Romanovsky
2020-06-04 13:23 ` Jason Gunthorpe
2020-06-04 14:59 ` Kees Cook
2020-06-04 17:57 ` Jason Gunthorpe
2020-06-04 19:09 ` Geert Uytterhoeven
2020-06-05 9:25 ` Kalle Valo
2020-06-03 23:32 ` [PATCH 10/10] compiler: Remove uninitialized_var() macro Kees Cook
2020-06-04 0:00 ` Bart Van Assche
2020-06-04 0:50 ` Miguel Ojeda
2020-06-04 1:23 ` [PATCH 00/10] " Sedat Dilek
2020-06-04 1:44 ` Kees Cook
2020-06-04 1:46 ` Sedat Dilek
2020-06-04 3:33 ` Nathan Chancellor
2020-06-04 7:26 ` Sedat Dilek
2020-06-04 14:27 ` Kees Cook
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