On Fri, 2022-10-07 at 12:35 -0500, Benjamin Marzinski wrote: > nvme:tcp devices set BLK_MQ_F_BLOCKING (they are the only block > devices > which multipath supports that do so), meaning that block_mq expects > that > they can block at certain points while servicing a request. However, > due to the way device-mapper sets up its queue, it is not able to set > BLK_MQ_F_BLOCKING when it includes paths that set this flag. Patches > were written to address this issue but they were rejected upstream > > https://lore.kernel.org/linux-block/YcH%2FE4JNag0QYYAa@xxxxxxxxxxxxx/T/#t > > The proposed solution was to have multipath use the bio queue_mode > for > multipath devices that include nvme:tcp paths. > > Multipath devices now automatically add the "queue_mode bio" feature > if > they include nvme:tcp paths. If a multipath devices was created with > "queue_mode rq", it will disallow the addition of nvme:tcp paths. > > Signed-off-by: Benjamin Marzinski <bmarzins@xxxxxxxxxx> Reviewed-by: Martin Wilck <mwilck@xxxxxxxx> > --- > libmultipath/configure.c | 17 ++++++++++++++++- > libmultipath/structs_vec.c | 7 +++++++ > multipath/multipath.conf.5 | 4 +++- > 3 files changed, 26 insertions(+), 2 deletions(-) > > diff --git a/libmultipath/configure.c b/libmultipath/configure.c > index 7c7babd9..e5249fc1 100644 > --- a/libmultipath/configure.c > +++ b/libmultipath/configure.c > @@ -260,6 +260,7 @@ int rr_optimize_path_order(struct pathgroup *pgp) > int setup_map(struct multipath *mpp, char **params, struct vectors > *vecs) > { > struct pathgroup * pgp; > + struct path *pp; > struct config *conf; > int i, marginal_pathgroups; > char *save_attr; > @@ -275,6 +276,14 @@ int setup_map(struct multipath *mpp, char > **params, struct vectors *vecs) > if (mpp->disable_queueing && VECTOR_SIZE(mpp->paths) != 0) > mpp->disable_queueing = 0; > > + /* Force QUEUE_MODE_BIO for maps with nvme:tcp paths */ > + vector_foreach_slot(mpp->paths, pp, i) { > + if (pp->bus == SYSFS_BUS_NVME && > + pp->sg_id.proto_id == NVME_PROTOCOL_TCP) { > + mpp->queue_mode = QUEUE_MODE_BIO; > + break; > + } > + } > /* > * If this map was created with add_map_without_path(), > * mpp->hwe might not be set yet. > @@ -1148,6 +1157,13 @@ int coalesce_paths (struct vectors *vecs, > vector mpvec, char *refwwid, > continue; > } > > + cmpp = find_mp_by_wwid(curmp, pp1->wwid); > + if (cmpp && cmpp->queue_mode == QUEUE_MODE_RQ && > + pp1->bus == SYSFS_BUS_NVME && pp1->sg_id.proto_id > == > + NVME_PROTOCOL_TCP) { > + orphan_path(pp1, "nvme:tcp path not allowed > with request queue_mode multipath device"); > + continue; > + } > /* > * at this point, we know we really got a new mp > */ > @@ -1186,7 +1202,6 @@ int coalesce_paths (struct vectors *vecs, > vector mpvec, char *refwwid, > } > verify_paths(mpp); > > - cmpp = find_mp_by_wwid(curmp, mpp->wwid); > if (cmpp) > mpp->queue_mode = cmpp->queue_mode; > if (setup_map(mpp, ¶ms, vecs)) { > diff --git a/libmultipath/structs_vec.c b/libmultipath/structs_vec.c > index 645896c6..5a618767 100644 > --- a/libmultipath/structs_vec.c > +++ b/libmultipath/structs_vec.c > @@ -264,6 +264,13 @@ int adopt_paths(vector pathvec, struct multipath > *mpp) > } > if (pp->initialized == INIT_REMOVED) > continue; > + if (mpp->queue_mode == QUEUE_MODE_RQ && > + pp->bus == SYSFS_BUS_NVME && > + pp->sg_id.proto_id == NVME_PROTOCOL_TCP) > { > + condlog(2, "%s: mulitpath device %s > created with request queue_mode. Unable to add nvme:tcp paths", > + pp->dev, mpp->alias); > + continue; > + } > if (!mpp->paths && !(mpp->paths = > vector_alloc())) > goto err; > > diff --git a/multipath/multipath.conf.5 b/multipath/multipath.conf.5 > index 07476497..1fea9d5a 100644 > --- a/multipath/multipath.conf.5 > +++ b/multipath/multipath.conf.5 > @@ -463,7 +463,9 @@ Before kernel 4.20 The default depends on the > kernel parameter > \fBdm_mod.use_blk_mq\fR. It is \fImq\fR if the latter is set, and > \fIrq\fR > otherwise. Since kernel 4.20, \fIrq\fR and \fImq\fR both correspond > to > block-multiqueue. Once a multipath device has been created, its > queue_mode > -cannot be changed. > +cannot be changed. \fInvme:tcp\fR paths are only supported in > multipath > +devices with queue_mode set to \fIbio\fR. multipath will > automatically > +set this when creating a device with \fInvme:tcp\fR paths. > .TP > The default is: \fB<unset>\fR > .RE -- dm-devel mailing list dm-devel@xxxxxxxxxx https://listman.redhat.com/mailman/listinfo/dm-devel
