On Mon, Feb 28, 2022 at 07:59:06PM -0800, Ira Weiny wrote: > On Tue, Feb 22, 2022 at 04:51:52PM +0100, Christoph Hellwig wrote: > > Using local kmaps slightly reduces the chances to stray writes, and > > the bvec interface cleans up the code a little bit. > > > > Signed-off-by: Christoph Hellwig <hch@xxxxxx> > > --- > > drivers/nvdimm/btt.c | 10 ++++------ > > 1 file changed, 4 insertions(+), 6 deletions(-) > > > > diff --git a/drivers/nvdimm/btt.c b/drivers/nvdimm/btt.c > > index cbd994f7f1fe6..9613e54c7a675 100644 > > --- a/drivers/nvdimm/btt.c > > +++ b/drivers/nvdimm/btt.c > > @@ -1163,17 +1163,15 @@ static int btt_rw_integrity(struct btt *btt, struct bio_integrity_payload *bip, > > */ > > > > cur_len = min(len, bv.bv_len); > > - mem = kmap_atomic(bv.bv_page); > > + mem = bvec_kmap_local(&bv); > > if (rw) > > - ret = arena_write_bytes(arena, meta_nsoff, > > - mem + bv.bv_offset, cur_len, > > + ret = arena_write_bytes(arena, meta_nsoff, mem, cur_len, > > Why drop bv.bv_offset here and below? Because bvec_kmap_local includes bv_offset in the pointer that it returns.
