We are reading the memory location, so we have to have a memory
constraint in there purely for the sake of showing the data flow
to the compiler.
Reported-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

(cherry picked from commit 5a2b59d3)
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>