zfsonlinux/zfs — pull request #2770 by behlendorf (2014-10-07 20:34:58+00:00)
Title: Fix CPU_SEQID use in preemptible context

Commit e022864 introduced a regression for kernels which are built
with CONFIG_DEBUG_PREEMPT. The use of CPU_SEQID in a preemptible
context causes zio_nowait() to trigger the BUG. Since CPU_SEQID
is simply being used as a random index the usage here is safe. To
resolve the issue preempt is disable while calling CPU_SEQID.