Add the necessary functions in the SRP transport module to allow
an SRP initiator driver to implement transport error handling.
This includes:
- Support for implementing fast_io_fail_tmo, the time that should
elapse after having detected a transport layer problem and
before failing I/O.
- Support for implementing dev_loss_tmo, the time that should
elapse after having detected a transport layer problem and
before removing a remote port.
Cc: FUJITA Tomonori <fujita.tomonori@xxxxxxxxxxxxx>
Cc: Robert Jennings <rcj@xxxxxxxxxxxxxxxxxx>
Cc: David Dillow <dillowda@xxxxxxxx>
Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
---
Documentation/ABI/stable/sysfs-transport-srp | 17 +++
drivers/scsi/scsi_transport_srp.c | 192 +++++++++++++++++++++++++-
include/scsi/scsi_transport_srp.h | 10 +-
3 files changed, 216 insertions(+), 3 deletions(-)
diff --git a/Documentation/ABI/stable/sysfs-transport-srp b/Documentation/ABI/stable/sysfs-transport-srp
index b36fb0d..2f14a5b 100644
--- a/Documentation/ABI/stable/sysfs-transport-srp
+++ b/Documentation/ABI/stable/sysfs-transport-srp
@@ -5,6 +5,23 @@ Contact: linux-scsi@xxxxxxxxxxxxxxx, linux-rdma@xxxxxxxxxxxxxxx
Description: Instructs an SRP initiator to disconnect from a target and to
remove all LUNs imported from that target.
+What: /sys/class/srp_remote_ports/port-<h>:<n>/dev_loss_tmo
+Date: January 1, 2012
+KernelVersion: 3.7
+Contact: linux-scsi@xxxxxxxxxxxxxxx, linux-rdma@xxxxxxxxxxxxxxx
+Description: Number of seconds the SCSI layer will wait after a transport
+ layer error has been observed before removing a target port.
+ Zero means immediate removal.
+
+What: /sys/class/srp_remote_ports/port-<h>:<n>/fast_io_fail_tmo
+Date: January 1, 2012
+KernelVersion: 3.7
+Contact: linux-scsi@xxxxxxxxxxxxxxx, linux-rdma@xxxxxxxxxxxxxxx
+Description: Number of seconds the SCSI layer will wait after a transport
+ layer error has been observed before failing I/O. Zero means
+ immediate removal. A negative value will disable this
+ behavior.
+
What: /sys/class/srp_remote_ports/port-<h>:<n>/port_id
Date: June 27, 2007
KernelVersion: 2.6.24
diff --git a/drivers/scsi/scsi_transport_srp.c b/drivers/scsi/scsi_transport_srp.c
index f379c7f..8b452c6 100644
--- a/drivers/scsi/scsi_transport_srp.c
+++ b/drivers/scsi/scsi_transport_srp.c
@@ -30,6 +30,7 @@
#include <scsi/scsi_host.h>
#include <scsi/scsi_transport.h>
#include <scsi/scsi_transport_srp.h>
+#include "scsi_priv.h"
#include "scsi_transport_srp_internal.h"
struct srp_host_attrs {
@@ -38,7 +39,7 @@ struct srp_host_attrs {
#define to_srp_host_attrs(host) ((struct srp_host_attrs *)(host)->shost_data)
#define SRP_HOST_ATTRS 0
-#define SRP_RPORT_ATTRS 3
+#define SRP_RPORT_ATTRS 5
struct srp_internal {
struct scsi_transport_template t;
@@ -54,6 +55,10 @@ struct srp_internal {
#define dev_to_rport(d) container_of(d, struct srp_rport, dev)
#define transport_class_to_srp_rport(dev) dev_to_rport((dev)->parent)
+static inline struct Scsi_Host *rport_to_shost(struct srp_rport *r)
+{
+ return dev_to_shost(r->dev.parent);
+}
static int srp_host_setup(struct transport_container *tc, struct device *dev,
struct device *cdev)
@@ -134,6 +139,175 @@ static ssize_t store_srp_rport_delete(struct device *dev,
static DEVICE_ATTR(delete, S_IWUSR, NULL, store_srp_rport_delete);
+/**
+ * srp_tmo_valid() - Check timeout combination validity.
+ *
+ * If no fast I/O fail timeout has been configured then the device loss timeout
+ * must be below SCSI_DEVICE_BLOCK_MAX_TIMEOUT. If a fast I/O fail timeout has
+ * been configured then it must be below the device loss timeout.
+ */
+static int srp_tmo_valid(int fast_io_fail_tmo, unsigned dev_loss_tmo)
+{
+ return (fast_io_fail_tmo < 0 &&
+ dev_loss_tmo <= SCSI_DEVICE_BLOCK_MAX_TIMEOUT)
+ || (0 <= fast_io_fail_tmo &&
+ fast_io_fail_tmo < dev_loss_tmo &&
+ dev_loss_tmo < ULONG_MAX / HZ) ? 0 : -EINVAL;
+}
+
+static ssize_t show_srp_rport_fast_io_fail_tmo(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct srp_rport *rport = transport_class_to_srp_rport(dev);
+
+ if (rport->fast_io_fail_tmo >= 0)
+ return sprintf(buf, "%d\n", rport->fast_io_fail_tmo);
+ else
+ return sprintf(buf, "off\n");
+}
+
+static ssize_t store_srp_rport_fast_io_fail_tmo(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct srp_rport *rport = transport_class_to_srp_rport(dev);
+ char ch[16];
+ int res;
+ int fast_io_fail_tmo;
+
+ if (count >= 3 && memcmp(buf, "off", 3) == 0) {
+ fast_io_fail_tmo = -1;
+ } else {
+ sprintf(ch, "%.*s", min_t(int, sizeof(ch) - 1, count), buf);
+ res = kstrtoint(ch, 0, &fast_io_fail_tmo);
+ if (res)
+ goto out;
+ }
+ res = srp_tmo_valid(fast_io_fail_tmo, rport->dev_loss_tmo);
+ if (res)
+ goto out;
+ rport->fast_io_fail_tmo = fast_io_fail_tmo;
+ res = count;
+out:
+ return res;
+}
+
+static DEVICE_ATTR(fast_io_fail_tmo, S_IRUGO | S_IWUSR,
+ show_srp_rport_fast_io_fail_tmo,
+ store_srp_rport_fast_io_fail_tmo);
+
+static ssize_t show_srp_rport_dev_loss_tmo(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct srp_rport *rport = transport_class_to_srp_rport(dev);
+
+ return sprintf(buf, "%u\n", rport->dev_loss_tmo);
+}
+
+static ssize_t store_srp_rport_dev_loss_tmo(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct srp_rport *rport = transport_class_to_srp_rport(dev);
+ char ch[16];
+ int res;
+ unsigned dev_loss_tmo;
+
+ sprintf(ch, "%.*s", min_t(int, sizeof(ch) - 1, count), buf);
+ res = kstrtouint(ch, 0, &dev_loss_tmo);
+ if (res)
+ goto out;
+ res = srp_tmo_valid(rport->fast_io_fail_tmo, dev_loss_tmo);
+ if (res)
+ goto out;
+ rport->dev_loss_tmo = dev_loss_tmo;
+ res = count;
+out:
+ return res;
+}
+
+static DEVICE_ATTR(dev_loss_tmo, S_IRUGO | S_IWUSR,
+ show_srp_rport_dev_loss_tmo,
+ store_srp_rport_dev_loss_tmo);
+
+/**
+ * rport_fast_io_fail_timedout() - Fast I/O failure timeout handler.
+ *
+ * Unblocks the SCSI host.
+ */
+static void rport_fast_io_fail_timedout(struct work_struct *work)
+{
+ struct srp_rport *rport =
+ container_of(to_delayed_work(work), struct srp_rport,
+ fast_io_fail_work);
+ struct Scsi_Host *shost;
+ struct srp_internal *i;
+
+ pr_err("SRP transport: fast_io_fail_tmo (%ds) expired - unblocking %s.\n",
+ rport->fast_io_fail_tmo, dev_name(&rport->dev));
+
+ shost = rport_to_shost(rport);
+ i = to_srp_internal(shost->transportt);
+ /* Involve the LLDD if possible to terminate all io on the rport. */
+ if (i->f->terminate_rport_io)
+ i->f->terminate_rport_io(rport);
+
+ scsi_target_unblock(rport->dev.parent, SDEV_TRANSPORT_OFFLINE);
+}
+
+/**
+ * rport_dev_loss_timedout() - Device loss timeout handler.
+ *
+ * Note: rport->ft->rport_delete must either unblock the SCSI host or schedule
+ * SCSI host removal.
+ */
+static void rport_dev_loss_timedout(struct work_struct *work)
+{
+ struct srp_rport *rport =
+ container_of(to_delayed_work(work), struct srp_rport,
+ dev_loss_work);
+ struct Scsi_Host *shost;
+ struct srp_internal *i;
+
+ pr_err("SRP transport: dev_loss_tmo (%ds) expired - removing %s.\n",
+ rport->dev_loss_tmo, dev_name(&rport->dev));
+
+ shost = rport_to_shost(rport);
+ i = to_srp_internal(shost->transportt);
+ BUG_ON(!i->f);
+ BUG_ON(!i->f->rport_delete);
+
+ i->f->rport_delete(rport);
+}
+
+/**
+ * srp_start_tl_fail_timers() - Start the transport layer failure timers.
+ * @rport: rport on which to start the transport layer failure timers.
+ * @elapsed: Time in jiffies that has already elapsed since the failure.
+ *
+ * Start the transport layer fast I/O failure and device loss timers. Do not
+ * modify a timer that was already started.
+ */
+void srp_start_tl_fail_timers(struct srp_rport *rport, int elapsed)
+{
+ if (rport->fast_io_fail_tmo >= 0)
+ queue_delayed_work(system_long_wq, &rport->fast_io_fail_work,
+ max_t(long, 1UL * rport->fast_io_fail_tmo
+ * HZ - elapsed, 0));
+ queue_delayed_work(system_long_wq, &rport->dev_loss_work,
+ max_t(long, 1UL * rport->dev_loss_tmo * HZ - elapsed, 0));
+}
+EXPORT_SYMBOL(srp_start_tl_fail_timers);
+
+void srp_stop_tl_fail_timers(struct srp_rport *rport)
+{
+ cancel_delayed_work_sync(&rport->fast_io_fail_work);
+ cancel_delayed_work_sync(&rport->dev_loss_work);
+}
+EXPORT_SYMBOL(srp_stop_tl_fail_timers);
+
static void srp_rport_release(struct device *dev)
{
struct srp_rport *rport = dev_to_rport(dev);
@@ -210,6 +384,12 @@ struct srp_rport *srp_rport_add(struct Scsi_Host *shost,
memcpy(rport->port_id, ids->port_id, sizeof(rport->port_id));
rport->roles = ids->roles;
+ rport->fast_io_fail_tmo = -1;
+ rport->dev_loss_tmo = 60;
+ INIT_DELAYED_WORK(&rport->fast_io_fail_work,
+ rport_fast_io_fail_timedout);
+ INIT_DELAYED_WORK(&rport->dev_loss_work, rport_dev_loss_timedout);
+
id = atomic_inc_return(&to_srp_host_attrs(shost)->next_port_id);
dev_set_name(&rport->dev, "port-%d:%d", shost->host_no, id);
@@ -252,6 +432,11 @@ void srp_rport_del(struct srp_rport *rport)
struct device *dev = &rport->dev;
struct Scsi_Host *shost = dev_to_shost(dev->parent);
+ device_remove_file(dev, &dev_attr_fast_io_fail_tmo);
+ device_remove_file(dev, &dev_attr_dev_loss_tmo);
+ srp_stop_tl_fail_timers(rport);
+ scsi_target_unblock(rport->dev.parent, SDEV_RUNNING);
+
if (shost->active_mode & MODE_TARGET &&
rport->roles == SRP_RPORT_ROLE_INITIATOR)
srp_tgt_it_nexus_destroy(shost, (unsigned long)rport);
@@ -327,8 +512,11 @@ srp_attach_transport(struct srp_function_template *ft)
count = 0;
i->rport_attrs[count++] = &dev_attr_port_id;
i->rport_attrs[count++] = &dev_attr_roles;
- if (ft->rport_delete)
+ if (ft->rport_delete) {
+ i->rport_attrs[count++] = &dev_attr_dev_loss_tmo;
+ i->rport_attrs[count++] = &dev_attr_fast_io_fail_tmo;
i->rport_attrs[count++] = &dev_attr_delete;
+ }
i->rport_attrs[count++] = NULL;
BUG_ON(count > ARRAY_SIZE(i->rport_attrs));
diff --git a/include/scsi/scsi_transport_srp.h b/include/scsi/scsi_transport_srp.h
index ff0f04a..eb996db 100644
--- a/include/scsi/scsi_transport_srp.h
+++ b/include/scsi/scsi_transport_srp.h
@@ -23,11 +23,17 @@ struct srp_rport {
/* for initiator drivers */
- void *lld_data; /* LLD private data */
+ void *lld_data; /* LLD private data */
+
+ int fast_io_fail_tmo;
+ unsigned dev_loss_tmo;
+ struct delayed_work fast_io_fail_work;
+ struct delayed_work dev_loss_work;
};
struct srp_function_template {
/* for initiator drivers */
+ void (*terminate_rport_io)(struct srp_rport *rport);
void (*rport_delete)(struct srp_rport *rport);
/* for target drivers */
int (* tsk_mgmt_response)(struct Scsi_Host *, u64, u64, int);
@@ -41,6 +47,8 @@ extern void srp_release_transport(struct scsi_transport_template *);
extern struct srp_rport *srp_rport_add(struct Scsi_Host *,
struct srp_rport_identifiers *);
extern void srp_rport_del(struct srp_rport *);
+extern void srp_start_tl_fail_timers(struct srp_rport *rport, int elapsed);
+extern void srp_stop_tl_fail_timers(struct srp_rport *rport);
extern void srp_remove_host(struct Scsi_Host *);
--
1.7.10.4
--
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