On Tue, May 27, 2014 at 7:58 PM, Maurizio Lombardi <mlombard@xxxxxxxxxx> wrote: > On Tue, May 27, 2014 at 06:15:45PM +0800, Ming Lei wrote: >> >> If the page can be merged to last segment, it should have been >> covered by code in branch of 'if (bio->bi_vcnt > 0) ...', shouldn't it? >> >> Or maybe it is better to make that code cover your case since >> looks your case is similar with that one according to your commit >> log. >> > > I realized that maybe you mean this branch: > > if (bio->bi_vcnt > 1 && (BIOVEC_PHYS_MERGEABLE(bvec-1, bvec))) > > right? > In this case the branch is not even reached in the original code because > the function returned an error way before executing it (line 760) > > There was already a patchset trying to modify the code in a different way than mine: > > https://groups.google.com/forum/#!msg/linux.kernel/3IanUpBVhFQ/3Xbg3yLRFp4J > > but it has been ignored and in my opinion it takes a more > complicated approach. Looks your approach is simpler. But looks there is one problem if I understand correctly: __blk_recalc_rq_segments() may not cover the last vector because bio->bi_iter.bi_size isn't updated until the end of __bio_add_page(). But it shouldn't have been related with current virtio-blk problem. Thanks, -- Ming Lei -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
