What happens if we feed it a 3-element iovec array, one page in each?
AFAICS, bio_add_pc_page() is called for each of those pages, even if
the previous calls have failed - break is only out of the inner loop.
Sure, failure due to exceeded request size means that everything after
that one will fail, but what of e.g.
/*
* If the queue doesn't support SG gaps and adding this
* offset would create a gap, disallow it.
*/
if (bvec_gap_to_prev(q, prev, offset))
return 0;
in there? Won't we risk having the first and the third pages added, with
the second one quietly skipped? Jens, looks like it had come from you
(by way of jejb). Am I missing something subtle here?
