libnvdimm, btt: fix btt_rw_page not returning errors

libnvdimm, btt: fix btt_rw_page not returning errors

commit c13c43d54f2c6a3be1c675766778ac1ad8dfbfcc upstream.

btt_rw_page was not propagating errors frm btt_do_bvec, resulting in any
IO errors via the rw_page path going unnoticed. the pmem driver recently
fixed this in e10624f pmem: fail io-requests to known bad blocks
but same problem in BTT went neglected.

Fixes: 5212e11fde4d ("nd_btt: atomic sector updates")
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>