x86/init: fix build with CONFIG_SWAP=n

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@gmail.com>
Fixes: 377eeaa8e11f ("x86/speculation/l1tf: Limit swap file size to MAX_PA/2")
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
(cherry picked from commit 792adb90fa724ce07c0171cbc96b9215af4b1045)
Tested-by: Connor Kuehl <connor.kuehl@canonical.com>
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index be27e845dfa4458e7d40b82da084f084f60c5622..63a6f9fcaf20688702b3d8d505128e318a313430 100644 (file)
--- 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