From: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Date: Wed, 15 Mar 2023 11:31:25 +0000 (+0300)
Subject: um: fix MAX_ORDER usage in linux_main()
X-Git-Tag: v6.6.7~2970^2~270
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=254ca6d261d4b6ce00591de110f6f96c3556dfbe;p=platform%2Fkernel%2Flinux-starfive.git

um: fix MAX_ORDER usage in linux_main()

MAX_ORDER is not inclusive: the maximum allocation order buddy allocator
can deliver is MAX_ORDER-1.

Fix MAX_ORDER usage in linux_main().

Link: https://lkml.kernel.org/r/20230315113133.11326-3-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c
index 8dcda61..5e5a9c8 100644
--- a/arch/um/kernel/um_arch.c
+++ b/arch/um/kernel/um_arch.c
@@ -368,10 +368,10 @@ int __init linux_main(int argc, char **argv)
 	max_physmem = TASK_SIZE - uml_physmem - iomem_size - MIN_VMALLOC;
 
 	/*
-	 * Zones have to begin on a 1 << MAX_ORDER page boundary,
+	 * Zones have to begin on a 1 << MAX_ORDER-1 page boundary,
 	 * so this makes sure that's true for highmem
 	 */
-	max_physmem &= ~((1 << (PAGE_SHIFT + MAX_ORDER)) - 1);
+	max_physmem &= ~((1 << (PAGE_SHIFT + MAX_ORDER - 1)) - 1);
 	if (physmem_size + iomem_size > max_physmem) {
 		highmem = physmem_size + iomem_size - max_physmem;
 		physmem_size -= highmem;