[PATCH 6/8] x86/init: fix build with CONFIG_SWAP=n

[Andrea Righi]

From: Vlastimil Babka <vbabka at suse.cz>

BugLink: https://bugs.launchpad.net/bugs/1830433

The introduction of generic_max_swapfile_size and arch-specific versions has
broken linking on x86 with CONFIG_SWAP=n due to undefined reference to
'generic_max_swapfile_size'. Fix it by compiling the x86-specific
max_swapfile_size() only with CONFIG_SWAP=y.

Reported-by: Tomas Pruzina <pruzinat at gmail.com>
Fixes: 377eeaa8e11f ("x86/speculation/l1tf: Limit swap file size to MAX_PA/2")
Signed-off-by: Vlastimil Babka <vbabka at suse.cz>
Cc: stable at vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds at linux-foundation.org>
(cherry picked from commit 792adb90fa724ce07c0171cbc96b9215af4b1045)
Tested-by: Connor Kuehl <connor.kuehl at canonical.com>
Signed-off-by: Andrea Righi <andrea.righi at canonical.com>
---
 arch/x86/mm/init.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index be27e845dfa4..63a6f9fcaf20 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -914,6 +914,7 @@ void update_cache_mode_entry(unsigned entry, enum page_cache_mode cache)
 	__pte2cachemode_tbl[entry] = cache;
 }
 
+#ifdef CONFIG_SWAP
 unsigned long max_swapfile_size(void)
 {
 	unsigned long pages;
@@ -934,3 +935,4 @@ unsigned long max_swapfile_size(void)
 	}
 	return pages;
 }
+#endif
-- 
2.20.1