Revision ad0eab9293485d1c06237e9249f6d4dfa3d93d4d authored by Paul Mackerras on 13 November 2014, 09:15:23 UTC, committed by Al Viro on 13 November 2014, 18:28:55 UTC
The branches of the if (i->type & ITER_BVEC) statement in iov_iter_single_seg_count() are the wrong way around; if ITER_BVEC is clear then we use i->bvec, when we should be using i->iov. This fixes it. In my case, the symptom that this caused was that a KVM guest doing filesystem operations on a virtual disk would result in one of qemu's threads on the host going into an infinite loop in generic_perform_write(). The loop would hit the copied == 0 case and call iov_iter_single_seg_count() to reduce the number of bytes to try to process, but because of the error, iov_iter_single_seg_count() would just return i->count and the loop made no progress and continued forever. Cc: stable@vger.kernel.org # 3.16+ Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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