Hey Kent, Digging a bit in the LKML archive I think this patch is in response to this thread: https://lkml.org/lkml/2013/11/6/27
Might be good to give context for which reported problem(s) are being fixed by this patch. On Tue, Nov 05 2013 at 10:48pm -0500, Kent Overstreet <k...@daterainc.com> wrote: > This patch reverts the default behaviour introduced by > 9fc6286f347d00528adcdcf12396d220f47492ed - bio_clone_biovec() no clonger > shares the source bio's biovec, cloning the biovec is once again the > default. Your focus, in terms of revert, seems to be on restoring bio_clone_bioset, so: s/bio_clone_biovec/bio_clone_bioset/ Maybe best to say "effectively reverts" since you aren't reverting 9fc6286f347d00528adcdcf12396d220f47492ed ? Also s/clonger/longer/ typo ^ > Instead, we add a new bio_clone_biovec_fast(), which creates a clone > that shares the source's biovec. This patch changes bcache and md to use s/md/dm/ > __bio_clone_biovec_fast() since they're expecting the new behaviour due > to other refactoring; most of the other uses of bio_clone() should be > same to convert to the _fast() variant but that will be done more s/same/safe/ > incrementally in other patches (bio_split() in particular). > > Note that __bio_clone() isn't being readded - the reason being that with > immutable biovecs allocating the right number of biovecs for the new > clone is no longer trivial so we don't want drivers trying to do that > themselves. > > This patch also reverts febca1baea1cfe2d7a0271385d89b03d5fb34f94 - > __bio_clone_fast() should not be setting bi_vcnt for bios that do not > own the biovec (see Documentation/block/biovecs.txt for rationale) - in > short, not setting it might cause bugs in the short term but long term > it's likely to hide nastier more subtle bugs, we don't want code looking > at bi_vcnt at all for bios it does not own. However, this patch > _shouldn't_ cause any regressions because of this since we're reverting > back to the old bio_clone() behaviour. > > Signed-off-by: Kent Overstreet <k...@daterainc.com> > Cc: Jens Axboe <ax...@kernel.dk> > Cc: Chris Mason <chris.ma...@fusionio.com> > Cc: Mike Snitzer <snit...@redhat.com> > Cc: NeilBrown <ne...@suse.de> > Cc: Olof Johansson <o...@lixom.net> > --- > Chris, Olaf, can you two in particular test this? I have tested the bounce > buffer code (and bcache), but Jens told me today there was an md bug that I > _still_ can't find any emails about so I'm not sure what to test for that. /me assumes you really mean md here, given Chris's later reply in this thread. Relative to DM, this patch looks fine to me: Acked-by: Mike Snitzer <snit...@redhat.com> Thanks, Mike -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
