tree d1a17b68a4098b632c79103a2d2c2184b11cee6f
parent b57332b4105abf1d518d93886e547ee2f98cd414
author Al Viro <viro@zeniv.linux.org.uk> 1476121145 -0400
committer Al Viro <viro@zeniv.linux.org.uk> 1476122296 -0400

[btrfs] fix check_direct_IO() for non-iovec iterators

looking for duplicate ->iov_base makes sense only for
iovec-backed iterators; for kvec-backed ones it's pointless,
for bvec-backed ones it's pointless and broken on 32bit (we
walk through an array of struct bio_vec accessing them as if
they were struct iovec; works by accident on 64bit, but on
32bit it'll blow up) and for pipe-backed ones it's pointless
and ends up oopsing.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>