mm: memblock: make keeping memblock memory opt-in rather than opt-out

Most architectures do not need the memblock memory after the page
allocator is initialized, but only few enable ARCH_DISCARD_MEMBLOCK in the
arch Kconfig.

Replacing ARCH_DISCARD_MEMBLOCK with ARCH_KEEP_MEMBLOCK and inverting the
logic makes it clear which architectures actually use memblock after
system initialization and skips the necessity to add ARCH_DISCARD_MEMBLOCK
to the architectures that are still missing that option.

Link: http://lkml.kernel.org/r/1556102150-32517-1-git-send-email-rppt@linux.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Burton <paul.burton@mips.com>
Cc: James Hogan <jhogan@kernel.org>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 8 insertions, 8 deletions

diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index f7fb8f6a688f..072b6ee55e3f 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -500,13 +500,7 @@ static int locate_mem_hole_callback(struct resource *res, void *arg)
         return locate_mem_hole_bottom_up(start, end, kbuf);
 }
 
-#ifdef CONFIG_ARCH_DISCARD_MEMBLOCK
-static int kexec_walk_memblock(struct kexec_buf *kbuf,
-                               int (*func)(struct resource *, void *))
-{
-        return 0;
-}
-#else
+#ifdef CONFIG_ARCH_KEEP_MEMBLOCK
 static int kexec_walk_memblock(struct kexec_buf *kbuf,
                                int (*func)(struct resource *, void *))
 {
@@ -550,6 +544,12 @@ static int kexec_walk_memblock(struct kexec_buf *kbuf,
 
         return ret;
 }
+#else
+static int kexec_walk_memblock(struct kexec_buf *kbuf,
+                               int (*func)(struct resource *, void *))
+{
+        return 0;
+}
 #endif
 
 /**
@@ -589,7 +589,7 @@ int kexec_locate_mem_hole(struct kexec_buf *kbuf)
         if (kbuf->mem != KEXEC_BUF_MEM_UNKNOWN)
                 return 0;
 
-        if (IS_ENABLED(CONFIG_ARCH_DISCARD_MEMBLOCK))
+        if (!IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK))
                 ret = kexec_walk_resources(kbuf, locate_mem_hole_callback);
         else
                 ret = kexec_walk_memblock(kbuf, locate_mem_hole_callback);