memblock: add assertion for zero allocation alignment
This came to light when calling memblock allocator from arc port (for
copying flattended DT). If a "0" alignment is passed, the allocator
round_up() call incorrectly rounds up the size to 0.
round_up(num, alignto) => ((num - 1) | (alignto -1)) + 1
While the obvious allocation failure causes kernel to panic, it is better
to warn the caller to fix the code.
Tejun suggested that instead of BUG_ON(!align) - which might be
ineffective due to pending console init and such, it is better to WARN_ON,
and continue the boot with a reasonable default align.
Caller passing @size need not be handled similarly as the subsequent
panic will indicate that anyhow.
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/memblock.c b/mm/memblock.c
index b8d9147..2cce8b3 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -771,6 +771,9 @@
{
phys_addr_t found;
+ if (WARN_ON(!align))
+ align = __alignof__(long long);
+
/* align @size to avoid excessive fragmentation on reserved array */
size = round_up(size, align);