Memory region size is rounded down to page boundary and with sub-page
region it becomes 0 and there is no point to add an empty region.
Moreover, when the base is less than PAGE_SIZE we get a bogus size as
(base + size - 1) evaluates to -1.

The commit 8cccffc52694 ("of: check for size < 0 after rounding in
early_init_dt_add_memory_arch") introduced a test for wrap around for the
case when base is not page aligned, the same test can be used to ignore
sub-page region sizes.

Signed-off-by: Mike Rapoport <[email protected]>
---
 drivers/of/fdt.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index 6da20b9..e866745 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -1134,12 +1134,13 @@ void __init __weak early_init_dt_add_memory_arch(u64 
base, u64 size)
 {
        const u64 phys_offset = MIN_MEMBLOCK_ADDR;
 
+       if (size < PAGE_SIZE - (base & ~PAGE_MASK)) {
+               pr_warn("Ignoring memory block 0x%llx - 0x%llx\n",
+                       base, base + size);
+               return;
+       }
+
        if (!PAGE_ALIGNED(base)) {
-               if (size < PAGE_SIZE - (base & ~PAGE_MASK)) {
-                       pr_warn("Ignoring memory block 0x%llx - 0x%llx\n",
-                               base, base + size);
-                       return;
-               }
                size -= PAGE_SIZE - (base & ~PAGE_MASK);
                base = PAGE_ALIGN(base);
        }
-- 
2.7.4

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