This should pass "buf" to bvec_kunmap_irq() instead of "bv".  The api is
like kmap_atomic() instead of kmap().
Signed-off-by: NDan Carpenter <error27@gmail.com>
Acked-by: NGeoff Levand <geoff@infradead.org>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>