tree fee8829694480137eacc54987c49d8c845a084ef
parent 4961772560d2f19695c73ece943716033ad62ac2
author Al Viro <viro@zeniv.linux.org.uk> 1428121172 -0400
committer Al Viro <viro@zeniv.linux.org.uk> 1428805783 -0400

pcm: another weird API abuse

readv() and writev() should _not_ ignore all but the first ->iov_len,
among other things.  Really weird abuse of those syscalls - it
expects a vector element per channel, with identical lengths (it
actually assumes them to be identical - no checking is done).
readv() and writev() are really bad match for that.  Unfortunately,
userland API is userland API and we can't do anything about them.

Converted to ->read_iter/->write_iter.  Please, _please_ don't do
anything of that kind when designing new interfaces.

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