On Wed, Feb 19, 2014 at 01:07:14PM +0000, Lars Ellenberg wrote: > bch_generic_make_request_hack() tries to be smart, > and fake a bi_max_bvecs = bi_vcnt. I meant to include a cover letter with the Oops backtrace, and this: Note that this patch is relevant for 3.13 and before. With 3.14, this whole bch_generic_make_request_hack() function has been dropped already. Thanks, Lars > If those bios have been REQ_DISCARD, and get submitted to a driver > (md raid) that uses bio_clone, the clone will end up with bi_io_vec == NULL, > passed down the stack, end up in sd_prep_fn and blk_add_request_payload, > which then tries to use bio->bi_io_vec->page. > > Fix: try to be even smarter in bch_generic_make_request_hack(), > and always pretend to have at least bi_max_vecs of 1, > unless the incoming bio was already created without a single bvec. > > Signed-off-by: Lars Ellenberg <lars@xxxxxxxxxx> > --- > drivers/md/bcache/io.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/md/bcache/io.c b/drivers/md/bcache/io.c > index 9056632..a638ac6 100644 > --- a/drivers/md/bcache/io.c > +++ b/drivers/md/bcache/io.c > @@ -47,7 +47,7 @@ static void bch_generic_make_request_hack(struct bio *bio) > * > * To be taken out once immutable bvec stuff is in. > */ > - bio->bi_max_vecs = bio->bi_vcnt; > + bio->bi_max_vecs = bio->bi_vcnt ?: (bio->bi_io_vec ? 1 : 0); > > generic_make_request(bio); > } > -- > 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-bcache" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
