majianpeng <majianp...@gmail.com> writes: > When exec bio_alloc, the bi_rw is zero.But after calling bio_add_page, > it will use bi_rw. > Fox example, in functiion __bio_add_page,it will call merge_bvec_fn(). > The merge_bvec_fn of raid456 will use the bi_rw to judge the merge. >>> if ((bvm->bi_rw & 1) == WRITE) >>> return biovec->bv_len; /* always allow writes to be mergeable */ > > Signed-off-by: Jianpeng Ma <majianp...@gmail.com>
Good catch. How did you find this? Did you experience data corruption as a result of this oversight, reduced performance due to missed merge opportunities, or did you just notice it in reviewing the code? Reviewed-by: Jeff Moyer <jmo...@redhat.com> > > There are many place like this in kernel.If you think this patch ok, i will > correct those. > --- > fs/direct-io.c | 1 + > 1 files changed, 1 insertions(+), 0 deletions(-) > > diff --git a/fs/direct-io.c b/fs/direct-io.c > index 1faf4cb..77f0bbf 100644 > --- a/fs/direct-io.c > +++ b/fs/direct-io.c > @@ -349,6 +349,7 @@ dio_bio_alloc(struct dio *dio, struct dio_submit *sdio, > > bio->bi_bdev = bdev; > bio->bi_sector = first_sector; > + bio->bi_rw = dio->rw; > if (dio->is_async) > bio->bi_end_io = dio_bio_end_aio; > else -- 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/
