| Message ID | 5452416A.1010403@acm.org (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
On 10/30/2014 3:47 PM, Bart Van Assche wrote: > If a cable is pulled during LUN scanning it can happen that the > SRP rport and the SCSI host have been created but no LUNs have been > added to the SCSI host. Since multipathd only sends SCSI commands > to a SCSI target if one or more SCSI devices are present and since > there is no keepalive mechanism for IB queue pairs this means that > after a LUN scan failed and after a reconnect has succeeded no > data will be sent over the QP and hence that a subsequent cable > pull will not be detected. Avoid this by not creating an rport or > SCSI host if a cable is pulled during a SCSI LUN scan. > > Note: so far the above behavior has only been observed with the > kernel module parameter ch_count set to a value >= 2. > > Signed-off-by: Bart Van Assche <bvanassche@acm.org> > Cc: Sagi Grimberg <sagig@mellanox.com> > Cc: Sebastian Parschauer <sebastian.riemer@profitbricks.com> > --- > drivers/infiniband/ulp/srp/ib_srp.c | 60 +++++++++++++++++++++++++++++++------ > drivers/infiniband/ulp/srp/ib_srp.h | 1 + > 2 files changed, 52 insertions(+), 9 deletions(-) > > diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c > index 9608e7a..a662c29 100644 > --- a/drivers/infiniband/ulp/srp/ib_srp.c > +++ b/drivers/infiniband/ulp/srp/ib_srp.c > @@ -1111,6 +1111,10 @@ static int srp_rport_reconnect(struct srp_rport *rport) > int i, ret; > > srp_disconnect_target(target); > + > + if (target->state == SRP_TARGET_SCANNING) > + return -ENODEV; > + > /* > * Now get a new local CM ID so that we avoid confusing the target in > * case things are really fouled up. Doing so also ensures that all CM > @@ -2607,11 +2611,23 @@ static struct scsi_host_template srp_template = { > .shost_attrs = srp_host_attrs > }; > > +static int srp_sdev_count(struct Scsi_Host *host) > +{ > + struct scsi_device *sdev; > + int c = 0; > + > + shost_for_each_device(sdev, host) > + c++; > + > + return c; > +} > + > static int srp_add_target(struct srp_host *host, struct srp_target_port *target) > { > struct srp_rport_identifiers ids; > struct srp_rport *rport; > > + target->state = SRP_TARGET_SCANNING; > sprintf(target->target_name, "SRP.T10:%016llX", > (unsigned long long) be64_to_cpu(target->id_ext)); > > @@ -2634,11 +2650,26 @@ static int srp_add_target(struct srp_host *host, struct srp_target_port *target) > list_add_tail(&target->list, &host->target_list); > spin_unlock(&host->target_lock); > > - target->state = SRP_TARGET_LIVE; > - > scsi_scan_target(&target->scsi_host->shost_gendev, > 0, target->scsi_id, SCAN_WILD_CARD, 0); > > + if (!target->connected || target->qp_in_error) { > + shost_printk(KERN_INFO, target->scsi_host, > + PFX "SCSI scan failed - removing SCSI host\n"); > + srp_queue_remove_work(target); > + goto out; > + } > + > + pr_debug(PFX "%s: SCSI scan succeeded - detected %d LUNs\n", > + dev_name(&target->scsi_host->shost_gendev), > + srp_sdev_count(target->scsi_host)); > + > + spin_lock_irq(&target->lock); > + if (target->state == SRP_TARGET_SCANNING) > + target->state = SRP_TARGET_LIVE; > + spin_unlock_irq(&target->lock); > + > +out: > return 0; > } > > @@ -2982,6 +3013,12 @@ static ssize_t srp_create_target(struct device *dev, > target->tl_retry_count = 7; > target->queue_size = SRP_DEFAULT_QUEUE_SIZE; > > + /* > + * Avoid that the SCSI host can be removed by srp_remove_target() > + * before this function returns. > + */ > + scsi_host_get(target->scsi_host); > + > mutex_lock(&host->add_target_mutex); > > ret = srp_parse_options(buf, target); > @@ -3044,18 +3081,23 @@ static ssize_t srp_create_target(struct device *dev, > if (ret) > goto err_disconnect; > > - shost_printk(KERN_DEBUG, target->scsi_host, PFX > - "new target: id_ext %016llx ioc_guid %016llx pkey %04x service_id %016llx sgid %pI6 dgid %pI6\n", > - be64_to_cpu(target->id_ext), > - be64_to_cpu(target->ioc_guid), > - be16_to_cpu(target->path.pkey), > - be64_to_cpu(target->service_id), > - target->path.sgid.raw, target->path.dgid.raw); > + if (target->state != SRP_TARGET_REMOVED) { > + shost_printk(KERN_DEBUG, target->scsi_host, PFX > + "new target: id_ext %016llx ioc_guid %016llx pkey %04x service_id %016llx sgid %pI6 dgid %pI6\n", > + be64_to_cpu(target->id_ext), > + be64_to_cpu(target->ioc_guid), > + be16_to_cpu(target->path.pkey), > + be64_to_cpu(target->service_id), > + target->path.sgid.raw, target->orig_dgid); > + } > > ret = count; > > out: > mutex_unlock(&host->add_target_mutex); > + > + scsi_host_put(target->scsi_host); > + > return ret; > > err_disconnect: > diff --git a/drivers/infiniband/ulp/srp/ib_srp.h b/drivers/infiniband/ulp/srp/ib_srp.h > index e46ecb1..00c7c48 100644 > --- a/drivers/infiniband/ulp/srp/ib_srp.h > +++ b/drivers/infiniband/ulp/srp/ib_srp.h > @@ -73,6 +73,7 @@ enum { > }; > > enum srp_target_state { > + SRP_TARGET_SCANNING, > SRP_TARGET_LIVE, > SRP_TARGET_REMOVED, > }; > This looks OK to me. Reviewed-by: Sagi Grimberg <sagig@mellanox.com> -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c index 9608e7a..a662c29 100644 --- a/drivers/infiniband/ulp/srp/ib_srp.c +++ b/drivers/infiniband/ulp/srp/ib_srp.c @@ -1111,6 +1111,10 @@ static int srp_rport_reconnect(struct srp_rport *rport) int i, ret; srp_disconnect_target(target); + + if (target->state == SRP_TARGET_SCANNING) + return -ENODEV; + /* * Now get a new local CM ID so that we avoid confusing the target in * case things are really fouled up. Doing so also ensures that all CM @@ -2607,11 +2611,23 @@ static struct scsi_host_template srp_template = { .shost_attrs = srp_host_attrs }; +static int srp_sdev_count(struct Scsi_Host *host) +{ + struct scsi_device *sdev; + int c = 0; + + shost_for_each_device(sdev, host) + c++; + + return c; +} + static int srp_add_target(struct srp_host *host, struct srp_target_port *target) { struct srp_rport_identifiers ids; struct srp_rport *rport; + target->state = SRP_TARGET_SCANNING; sprintf(target->target_name, "SRP.T10:%016llX", (unsigned long long) be64_to_cpu(target->id_ext)); @@ -2634,11 +2650,26 @@ static int srp_add_target(struct srp_host *host, struct srp_target_port *target) list_add_tail(&target->list, &host->target_list); spin_unlock(&host->target_lock); - target->state = SRP_TARGET_LIVE; - scsi_scan_target(&target->scsi_host->shost_gendev, 0, target->scsi_id, SCAN_WILD_CARD, 0); + if (!target->connected || target->qp_in_error) { + shost_printk(KERN_INFO, target->scsi_host, + PFX "SCSI scan failed - removing SCSI host\n"); + srp_queue_remove_work(target); + goto out; + } + + pr_debug(PFX "%s: SCSI scan succeeded - detected %d LUNs\n", + dev_name(&target->scsi_host->shost_gendev), + srp_sdev_count(target->scsi_host)); + + spin_lock_irq(&target->lock); + if (target->state == SRP_TARGET_SCANNING) + target->state = SRP_TARGET_LIVE; + spin_unlock_irq(&target->lock); + +out: return 0; } @@ -2982,6 +3013,12 @@ static ssize_t srp_create_target(struct device *dev, target->tl_retry_count = 7; target->queue_size = SRP_DEFAULT_QUEUE_SIZE; + /* + * Avoid that the SCSI host can be removed by srp_remove_target() + * before this function returns. + */ + scsi_host_get(target->scsi_host); + mutex_lock(&host->add_target_mutex); ret = srp_parse_options(buf, target); @@ -3044,18 +3081,23 @@ static ssize_t srp_create_target(struct device *dev, if (ret) goto err_disconnect; - shost_printk(KERN_DEBUG, target->scsi_host, PFX - "new target: id_ext %016llx ioc_guid %016llx pkey %04x service_id %016llx sgid %pI6 dgid %pI6\n", - be64_to_cpu(target->id_ext), - be64_to_cpu(target->ioc_guid), - be16_to_cpu(target->path.pkey), - be64_to_cpu(target->service_id), - target->path.sgid.raw, target->path.dgid.raw); + if (target->state != SRP_TARGET_REMOVED) { + shost_printk(KERN_DEBUG, target->scsi_host, PFX + "new target: id_ext %016llx ioc_guid %016llx pkey %04x service_id %016llx sgid %pI6 dgid %pI6\n", + be64_to_cpu(target->id_ext), + be64_to_cpu(target->ioc_guid), + be16_to_cpu(target->path.pkey), + be64_to_cpu(target->service_id), + target->path.sgid.raw, target->orig_dgid); + } ret = count; out: mutex_unlock(&host->add_target_mutex); + + scsi_host_put(target->scsi_host); + return ret; err_disconnect: diff --git a/drivers/infiniband/ulp/srp/ib_srp.h b/drivers/infiniband/ulp/srp/ib_srp.h index e46ecb1..00c7c48 100644 --- a/drivers/infiniband/ulp/srp/ib_srp.h +++ b/drivers/infiniband/ulp/srp/ib_srp.h @@ -73,6 +73,7 @@ enum { }; enum srp_target_state { + SRP_TARGET_SCANNING, SRP_TARGET_LIVE, SRP_TARGET_REMOVED, };
If a cable is pulled during LUN scanning it can happen that the SRP rport and the SCSI host have been created but no LUNs have been added to the SCSI host. Since multipathd only sends SCSI commands to a SCSI target if one or more SCSI devices are present and since there is no keepalive mechanism for IB queue pairs this means that after a LUN scan failed and after a reconnect has succeeded no data will be sent over the QP and hence that a subsequent cable pull will not be detected. Avoid this by not creating an rport or SCSI host if a cable is pulled during a SCSI LUN scan. Note: so far the above behavior has only been observed with the kernel module parameter ch_count set to a value >= 2. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Cc: Sagi Grimberg <sagig@mellanox.com> Cc: Sebastian Parschauer <sebastian.riemer@profitbricks.com> --- drivers/infiniband/ulp/srp/ib_srp.c | 60 +++++++++++++++++++++++++++++++------ drivers/infiniband/ulp/srp/ib_srp.h | 1 + 2 files changed, 52 insertions(+), 9 deletions(-)