BugLink: http://bugs.launchpad.net/bugs/1768825

commit 6510bbc8 upstream.

Currently it is possible to read and/or write to suspend EB's.
Writing /dev/mtdX or /dev/mtdblockX from several processes may
break the flash state machine.
Signed-off-by: Joakim Tjernlund <joakim.tjernlund@infinera.com>
Cc: <stable@vger.kernel.org>
Reviewed-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>