Re: [PATCH v10 27/27] mm: display pkey in smaps if arch_pkeys_enabled() is true

On Tue, Jan 30, 2018 at 01:16:11PM +0100, Michal Hocko wrote:

On Thu 18-01-18 17:50:48, Ram Pai wrote:
[...]

quoted

@@ -851,9 +848,13 @@ static int show_smap(struct seq_file *m, void *v, int is_pid)
 			   (unsigned long)(mss->pss >> (10 + PSS_SHIFT)));
 
 	if (!rollup_mode) {
-		arch_show_smap(m, vma);
+#ifdef CONFIG_ARCH_HAS_PKEYS
+		if (arch_pkeys_enabled())
+			seq_printf(m, "ProtectionKey:  %8u\n", vma_pkey(vma));
+#endif
 		show_smap_vma_flags(m, vma);
 	}
+

Why do you need to add ifdef here? The previous patch should make
arch_pkeys_enabled == F when CONFIG_ARCH_HAS_PKEYS=n.

You are right. it need not be wrapped in CONFIG_ARCH_HAS_PKEYS.  I had to do it
because vma_pkey(vma)  is not defined in some architectures.

I will provide a generic vma_pkey() definition for architectures that do 
not support PKEYS.

Btw. could you
merge those two patches into one. It is usually much easier to review a
new helper function if it is added along with a user.

ok.

Thanks,
RP