[PATCH 0/10] IB SRP initiator patches for kernel 3.12

[PATCH 0/10] IB SRP initiator patches for kernel 3.12

[Bart Van Assche]

The purpose of this InfiniBand SRP initiator patch series is as follows:
- Make the SRP initiator driver better suited for use in a H.A. setup.
   Add fast_io_fail_tmo, dev_loss_tmo and reconnect_delay parameters.
   With the default values of these parameters failover happens
   significantly faster. The dev_loss mechanism can be disabled which
   makes it possible to avoid device removal which is necessary when
   e.g. using initiator side mirroring.
- Improve performance by making the queue size configurable.
- Make it possible to figure out which SCSI host corresponds to which
   SRP initiator port by making the SGID (source GID) available in sysfs.

The changes since the previous version of this patch series are as 
follows (see also http://thread.gmane.org/gmane.linux.drivers.rdma/17058/):
- Split the scsi_transport_srp changes in two patches to make review
   easier.
- Added a patch for exporting the SGID via sysfs.
- Included a few fixes for the rport state transition algorithm for
   issues discovered while testing this patch series on a larger setup
   (initiator with 4 IB ports and target with 8 IB ports or 32 SRP
   paths between initiator and target in total).

The individual patches in this series are:
0001-IB-srp-Make-transport-layer-retry-count-configurable.patch
0002-IB-srp-Keep-rport-as-long-as-the-IB-transport-layer.patch
0003-scsi_transport_srp-Add-transport-layer-error-handlin.patch
0004-IB-srp-Use-SRP-transport-layer-error-recovery.patch
0005-IB-srp-Start-timers-if-a-transport-layer-error-occur.patch
0006-scsi_transport_srp-Add-periodic-reconnect-support.patch
0007-IB-srp-Add-periodic-reconnect-functionality.patch
0008-IB-srp-Export-sgid-to-sysfs.patch
0009-IB-srp-Introduce-srp_alloc_req_data.patch
0010-IB-srp-Make-queue-size-configurable.patch
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[PATCH 01/10] IB/srp: Make transport layer retry count configurable

[Bart Van Assche]

From: Vu Pham <vuhuong-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>

Allow the InfiniBand RC retry count to be configured by the user
as an option in the target login string. Reducing this retry count
allows to reduce the path failover time.

Signed-off-by: Vu Pham <vu-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
[bvanassche: Rewrote patch description / changed default retry count]
Signed-off-by: Bart Van Assche <bvanassche-HInyCGIudOg@public.gmane.org>
Acked-by: David Dillow <dillowda-1Heg1YXhbW8@public.gmane.org>
Cc: Roland Dreier <roland-BHEL68pLQRGGvPXPguhicg@public.gmane.org>
Cc: Sebastian Riemer <sebastian.riemer-EIkl63zCoXaH+58JC4qpiA@public.gmane.org>
---
 Documentation/ABI/stable/sysfs-driver-ib_srp |  2 ++
 drivers/infiniband/ulp/srp/ib_srp.c          | 24 +++++++++++++++++++++++-
 drivers/infiniband/ulp/srp/ib_srp.h          |  1 +
 3 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/Documentation/ABI/stable/sysfs-driver-ib_srp b/Documentation/ABI/stable/sysfs-driver-ib_srp
index 5c53d28..18e9b27 100644
--- a/Documentation/ABI/stable/sysfs-driver-ib_srp
+++ b/Documentation/ABI/stable/sysfs-driver-ib_srp
@@ -61,6 +61,8 @@ Description:	Interface for making ib_srp connect to a new target.
 		  interrupt is handled by a different CPU then the comp_vector
 		  parameter can be used to spread the SRP completion workload
 		  over multiple CPU's.
+		* tl_retry_count, a number in the range 2..7 specifying the
+		  IB RC retry count.
 
 What:		/sys/class/infiniband_srp/srp-<hca>-<port_number>/ibdev
 Date:		January 2, 2006
diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index 17b58f4..aed5b75 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -390,7 +390,7 @@ static int srp_send_req(struct srp_target_port *target)
 	req->param.responder_resources	      = 4;
 	req->param.remote_cm_response_timeout = 20;
 	req->param.local_cm_response_timeout  = 20;
-	req->param.retry_count 		      = 7;
+	req->param.retry_count                = target->tl_retry_count;
 	req->param.rnr_retry_count 	      = 7;
 	req->param.max_cm_retries 	      = 15;
 
@@ -1907,6 +1907,14 @@ static ssize_t show_comp_vector(struct device *dev,
 	return sprintf(buf, "%d\n", target->comp_vector);
 }
 
+static ssize_t show_tl_retry_count(struct device *dev,
+				   struct device_attribute *attr, char *buf)
+{
+	struct srp_target_port *target = host_to_target(class_to_shost(dev));
+
+	return sprintf(buf, "%d\n", target->tl_retry_count);
+}
+
 static ssize_t show_cmd_sg_entries(struct device *dev,
 				   struct device_attribute *attr, char *buf)
 {
@@ -1934,6 +1942,7 @@ static DEVICE_ATTR(zero_req_lim,    S_IRUGO, show_zero_req_lim,	   NULL);
 static DEVICE_ATTR(local_ib_port,   S_IRUGO, show_local_ib_port,   NULL);
 static DEVICE_ATTR(local_ib_device, S_IRUGO, show_local_ib_device, NULL);
 static DEVICE_ATTR(comp_vector,     S_IRUGO, show_comp_vector,     NULL);
+static DEVICE_ATTR(tl_retry_count,  S_IRUGO, show_tl_retry_count,  NULL);
 static DEVICE_ATTR(cmd_sg_entries,  S_IRUGO, show_cmd_sg_entries,  NULL);
 static DEVICE_ATTR(allow_ext_sg,    S_IRUGO, show_allow_ext_sg,    NULL);
 
@@ -1949,6 +1958,7 @@ static struct device_attribute *srp_host_attrs[] = {
 	&dev_attr_local_ib_port,
 	&dev_attr_local_ib_device,
 	&dev_attr_comp_vector,
+	&dev_attr_tl_retry_count,
 	&dev_attr_cmd_sg_entries,
 	&dev_attr_allow_ext_sg,
 	NULL
@@ -2073,6 +2083,7 @@ enum {
 	SRP_OPT_ALLOW_EXT_SG	= 1 << 10,
 	SRP_OPT_SG_TABLESIZE	= 1 << 11,
 	SRP_OPT_COMP_VECTOR	= 1 << 12,
+	SRP_OPT_TL_RETRY_COUNT	= 1 << 13,
 	SRP_OPT_ALL		= (SRP_OPT_ID_EXT	|
 				   SRP_OPT_IOC_GUID	|
 				   SRP_OPT_DGID		|
@@ -2094,6 +2105,7 @@ static const match_table_t srp_opt_tokens = {
 	{ SRP_OPT_ALLOW_EXT_SG,		"allow_ext_sg=%u"	},
 	{ SRP_OPT_SG_TABLESIZE,		"sg_tablesize=%u"	},
 	{ SRP_OPT_COMP_VECTOR,		"comp_vector=%u"	},
+	{ SRP_OPT_TL_RETRY_COUNT,	"tl_retry_count=%u"	},
 	{ SRP_OPT_ERR,			NULL 			}
 };
 
@@ -2257,6 +2269,15 @@ static int srp_parse_options(const char *buf, struct srp_target_port *target)
 			target->comp_vector = token;
 			break;
 
+		case SRP_OPT_TL_RETRY_COUNT:
+			if (match_int(args, &token) || token < 2 || token > 7) {
+				pr_warn("bad tl_retry_count parameter '%s' (must be a number between 2 and 7)\n",
+					p);
+				goto out;
+			}
+			target->tl_retry_count = token;
+			break;
+
 		default:
 			pr_warn("unknown parameter or missing value '%s' in target creation request\n",
 				p);
@@ -2311,6 +2332,7 @@ static ssize_t srp_create_target(struct device *dev,
 	target->cmd_sg_cnt	= cmd_sg_entries;
 	target->sg_tablesize	= indirect_sg_entries ? : cmd_sg_entries;
 	target->allow_ext_sg	= allow_ext_sg;
+	target->tl_retry_count	= 7;
 
 	ret = srp_parse_options(buf, target);
 	if (ret)
diff --git a/drivers/infiniband/ulp/srp/ib_srp.h b/drivers/infiniband/ulp/srp/ib_srp.h
index e641088..84d821b 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.h
+++ b/drivers/infiniband/ulp/srp/ib_srp.h
@@ -157,6 +157,7 @@ struct srp_target_port {
 	unsigned int		scsi_id;
 	unsigned int		sg_tablesize;
 	int			comp_vector;
+	int			tl_retry_count;
 
 	struct ib_sa_path_rec	path;
 	__be16			orig_dgid[8];
-- 
1.8.1.4

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[PATCH 02/10] IB/srp: Keep rport as long as the IB transport layer

[Bart Van Assche]

Keep the rport data structure around after srp_remove_host() has
finished until cleanup of the IB transport layer has finished
completely. This is necessary because later patches use the rport
pointer inside the queuecommand callback. Without this patch
accessing the rport from inside a queuecommand callback is racy
because srp_remove_host() must be invoked before scsi_remove_host()
and because the queuecommand callback could get invoked after
srp_remove_host() has finished. In other words, without this patch
the queuecommand callback can get invoked after the rport data
structure has been freed.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Cc: David Dillow <dillowda@ornl.gov>
Cc: Roland Dreier <roland@purestorage.com>
Cc: James Bottomley <JBottomley@Parallels.com>
Cc: Vu Pham <vu@mellanox.com>
Cc: Sebastian Riemer <sebastian.riemer@profitbricks.com>
---
 drivers/infiniband/ulp/srp/ib_srp.c |  3 +++
 drivers/infiniband/ulp/srp/ib_srp.h |  1 +
 drivers/scsi/scsi_transport_srp.c   | 18 ++++++++++++++++++
 include/scsi/scsi_transport_srp.h   |  2 ++
 4 files changed, 24 insertions(+)

diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index aed5b75..414fd02 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -528,11 +528,13 @@ static void srp_remove_target(struct srp_target_port *target)
 	WARN_ON_ONCE(target->state != SRP_TARGET_REMOVED);
 
 	srp_del_scsi_host_attr(target->scsi_host);
+	srp_rport_get(target->rport);
 	srp_remove_host(target->scsi_host);
 	scsi_remove_host(target->scsi_host);
 	srp_disconnect_target(target);
 	ib_destroy_cm_id(target->cm_id);
 	srp_free_target_ib(target);
+	srp_rport_put(target->rport);
 	srp_free_req_data(target);
 
 	spin_lock(&target->srp_host->target_lock);
@@ -2004,6 +2006,7 @@ static int srp_add_target(struct srp_host *host, struct srp_target_port *target)
 	}
 
 	rport->lld_data = target;
+	target->rport = rport;
 
 	spin_lock(&host->target_lock);
 	list_add_tail(&target->list, &host->target_list);
diff --git a/drivers/infiniband/ulp/srp/ib_srp.h b/drivers/infiniband/ulp/srp/ib_srp.h
index 84d821b..2a1768f 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.h
+++ b/drivers/infiniband/ulp/srp/ib_srp.h
@@ -153,6 +153,7 @@ struct srp_target_port {
 	u16			io_class;
 	struct srp_host	       *srp_host;
 	struct Scsi_Host       *scsi_host;
+	struct srp_rport       *rport;
 	char			target_name[32];
 	unsigned int		scsi_id;
 	unsigned int		sg_tablesize;
diff --git a/drivers/scsi/scsi_transport_srp.c b/drivers/scsi/scsi_transport_srp.c
index f379c7f..f7ba94a 100644
--- a/drivers/scsi/scsi_transport_srp.c
+++ b/drivers/scsi/scsi_transport_srp.c
@@ -185,6 +185,24 @@ static int srp_host_match(struct attribute_container *cont, struct device *dev)
 }
 
 /**
+ * srp_rport_get() - increment rport reference count
+ */
+void srp_rport_get(struct srp_rport *rport)
+{
+	get_device(&rport->dev);
+}
+EXPORT_SYMBOL(srp_rport_get);
+
+/**
+ * srp_rport_put() - decrement rport reference count
+ */
+void srp_rport_put(struct srp_rport *rport)
+{
+	put_device(&rport->dev);
+}
+EXPORT_SYMBOL(srp_rport_put);
+
+/**
  * srp_rport_add - add a SRP remote port to the device hierarchy
  * @shost:	scsi host the remote port is connected to.
  * @ids:	The port id for the remote port.
diff --git a/include/scsi/scsi_transport_srp.h b/include/scsi/scsi_transport_srp.h
index ff0f04a..5a2d2d1 100644
--- a/include/scsi/scsi_transport_srp.h
+++ b/include/scsi/scsi_transport_srp.h
@@ -38,6 +38,8 @@ extern struct scsi_transport_template *
 srp_attach_transport(struct srp_function_template *);
 extern void srp_release_transport(struct scsi_transport_template *);
 
+extern void srp_rport_get(struct srp_rport *rport);
+extern void srp_rport_put(struct srp_rport *rport);
 extern struct srp_rport *srp_rport_add(struct Scsi_Host *,
 				       struct srp_rport_identifiers *);
 extern void srp_rport_del(struct srp_rport *);
-- 
1.8.1.4

[PATCH 03/10] scsi_transport_srp: Add transport layer error handling

[Bart Van Assche]

Add the necessary functions in the SRP transport module to allow
an SRP initiator driver to implement transport layer error handling
similar to the functionality already provided by the FC transport
layer. 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.

Signed-off-by: Bart Van Assche <bvanassche-HInyCGIudOg@public.gmane.org>
Cc: David Dillow <dillowda-1Heg1YXhbW8@public.gmane.org>
Cc: Roland Dreier <roland-BHEL68pLQRGGvPXPguhicg@public.gmane.org>
Cc: James Bottomley <JBottomley-MU7nAjRaF3makBO8gow8eQ@public.gmane.org>
Cc: Vu Pham <vu-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
Cc: Sebastian Riemer <sebastian.riemer-EIkl63zCoXaH+58JC4qpiA@public.gmane.org>
---
 Documentation/ABI/stable/sysfs-transport-srp |  31 ++
 drivers/scsi/scsi_transport_srp.c            | 429 ++++++++++++++++++++++++++-
 include/scsi/scsi_transport_srp.h            |  74 ++++-
 3 files changed, 531 insertions(+), 3 deletions(-)

diff --git a/Documentation/ABI/stable/sysfs-transport-srp b/Documentation/ABI/stable/sysfs-transport-srp
index b36fb0d..178a44d 100644
--- a/Documentation/ABI/stable/sysfs-transport-srp
+++ b/Documentation/ABI/stable/sysfs-transport-srp
@@ -5,6 +5,24 @@ Contact:	linux-scsi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
 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:		December 1, 2013
+KernelVersion:	3.12
+Contact:	linux-scsi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
+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. Setting this attribute to "off"
+		will disable the dev_loss timer.
+
+What:		/sys/class/srp_remote_ports/port-<h>:<n>/fast_io_fail_tmo
+Date:		December 1, 2013
+KernelVersion:	3.12
+Contact:	linux-scsi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
+Description:	Number of seconds the SCSI layer will wait after a transport
+		layer error has been observed before failing I/O. Zero means
+		failing I/O immediately. Setting this attribute to "off" will
+		disable the fast_io_fail timer.
+
 What:		/sys/class/srp_remote_ports/port-<h>:<n>/port_id
 Date:		June 27, 2007
 KernelVersion:	2.6.24
@@ -17,3 +35,16 @@ Date:		June 27, 2007
 KernelVersion:	2.6.24
 Contact:	linux-scsi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
 Description:	Role of the remote port. Either "SRP Initiator" or "SRP Target".
+
+What:		/sys/class/srp_remote_ports/port-<h>:<n>/state
+Date:		December 1, 2013
+KernelVersion:	3.12
+Contact:	linux-scsi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
+Description:	State of the transport layer used for communication with the
+		remote port. "running" if the transport layer is operational;
+		"blocked" if a transport layer error has been encountered but
+		the fail_io_fast_tmo timer has not yet fired; "fail-fast"
+		after the fail_io_fast_tmo timer has fired and before the
+		"dev_loss_tmo" timer has fired; "lost" after the
+		"dev_loss_tmo" timer has fired and before the port is finally
+		removed.
diff --git a/drivers/scsi/scsi_transport_srp.c b/drivers/scsi/scsi_transport_srp.c
index f7ba94a..675e203 100644
--- a/drivers/scsi/scsi_transport_srp.c
+++ b/drivers/scsi/scsi_transport_srp.c
@@ -24,12 +24,15 @@
 #include <linux/err.h>
 #include <linux/slab.h>
 #include <linux/string.h>
+#include <linux/delay.h>
 
 #include <scsi/scsi.h>
+#include <scsi/scsi_cmnd.h>
 #include <scsi/scsi_device.h>
 #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 +41,7 @@ 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 6
 
 struct srp_internal {
 	struct scsi_transport_template t;
@@ -54,6 +57,34 @@ 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);
+}
+
+/**
+ * srp_tmo_valid() - check timeout combination validity
+ *
+ * The combination of the timeout parameters must be such that SCSI commands
+ * are finished in a reasonable time. Hence do not allow the fast I/O fail
+ * timeout to exceed SCSI_DEVICE_BLOCK_MAX_TIMEOUT. Furthermore, these
+ * parameters must be such that multipath can detect failed paths timely.
+ * Hence do not allow both parameters to be disabled simultaneously.
+ */
+int srp_tmo_valid(int fast_io_fail_tmo, int dev_loss_tmo)
+{
+	if (fast_io_fail_tmo < 0 && dev_loss_tmo < 0)
+		return -EINVAL;
+	if (fast_io_fail_tmo > SCSI_DEVICE_BLOCK_MAX_TIMEOUT)
+		return -EINVAL;
+	if (dev_loss_tmo >= LONG_MAX / HZ)
+		return -EINVAL;
+	if (fast_io_fail_tmo >= 0 && dev_loss_tmo >= 0 &&
+	    fast_io_fail_tmo >= dev_loss_tmo)
+		return -EINVAL;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(srp_tmo_valid);
 
 static int srp_host_setup(struct transport_container *tc, struct device *dev,
 			  struct device *cdev)
@@ -134,10 +165,382 @@ static ssize_t store_srp_rport_delete(struct device *dev,
 
 static DEVICE_ATTR(delete, S_IWUSR, NULL, store_srp_rport_delete);
 
+static ssize_t show_srp_rport_state(struct device *dev,
+				    struct device_attribute *attr,
+				    char *buf)
+{
+	static const char *const state_name[] = {
+		[SRP_RPORT_RUNNING]	= "running",
+		[SRP_RPORT_BLOCKED]	= "blocked",
+		[SRP_RPORT_FAIL_FAST]	= "fail-fast",
+		[SRP_RPORT_LOST]	= "lost",
+	};
+	struct srp_rport *rport = transport_class_to_srp_rport(dev);
+	enum srp_rport_state state = rport->state;
+
+	return sprintf(buf, "%s\n",
+		       (unsigned)state < ARRAY_SIZE(state_name) ?
+		       state_name[state] : "???");
+}
+
+static DEVICE_ATTR(state, S_IRUGO, show_srp_rport_state, NULL);
+
+static ssize_t srp_show_tmo(char *buf, int tmo)
+{
+	return tmo >= 0 ? sprintf(buf, "%d\n", tmo) : sprintf(buf, "off\n");
+}
+
+static int srp_parse_tmo(int *tmo, const char *buf)
+{
+	int res = 0;
+
+	if (strncmp(buf, "off", 3) != 0)
+		res = kstrtoint(buf, 0, tmo);
+	else
+		*tmo = -1;
+
+	return res;
+}
+
+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);
+
+	return srp_show_tmo(buf, rport->fast_io_fail_tmo);
+}
+
+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);
+	int res;
+	int fast_io_fail_tmo;
+
+	res = srp_parse_tmo(&fast_io_fail_tmo, buf);
+	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 srp_show_tmo(buf, 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);
+	int res;
+	int dev_loss_tmo;
+
+	res = srp_parse_tmo(&dev_loss_tmo, buf);
+	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);
+
+static int srp_rport_set_state(struct srp_rport *rport,
+			       enum srp_rport_state new_state)
+{
+	enum srp_rport_state old_state = rport->state;
+
+	lockdep_assert_held(&rport->mutex);
+
+	switch (new_state) {
+	case SRP_RPORT_RUNNING:
+		switch (old_state) {
+		case SRP_RPORT_LOST:
+			goto invalid;
+		default:
+			break;
+		}
+		break;
+	case SRP_RPORT_BLOCKED:
+		switch (old_state) {
+		case SRP_RPORT_RUNNING:
+			break;
+		default:
+			goto invalid;
+		}
+		break;
+	case SRP_RPORT_FAIL_FAST:
+		switch (old_state) {
+		case SRP_RPORT_LOST:
+			goto invalid;
+		default:
+			break;
+		}
+		break;
+	case SRP_RPORT_LOST:
+		break;
+	}
+	rport->state = new_state;
+	return 0;
+
+invalid:
+	return -EINVAL;
+}
+
+static void __rport_fail_io_fast(struct srp_rport *rport)
+{
+	struct Scsi_Host *shost = rport_to_shost(rport);
+	struct srp_internal *i;
+
+	lockdep_assert_held(&rport->mutex);
+
+	if (srp_rport_set_state(rport, SRP_RPORT_FAIL_FAST))
+		return;
+	scsi_target_unblock(rport->dev.parent, SDEV_TRANSPORT_OFFLINE);
+
+	/* Involve the LLD if possible to terminate all I/O on the rport. */
+	i = to_srp_internal(shost->transportt);
+	if (i->f->terminate_rport_io)
+		i->f->terminate_rport_io(rport);
+}
+
+/**
+ * rport_fast_io_fail_timedout() - fast I/O failure timeout handler
+ */
+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 = rport_to_shost(rport);
+
+	pr_info("fast_io_fail_tmo expired for SRP %s / %s.\n",
+		dev_name(&rport->dev), dev_name(&shost->shost_gendev));
+
+	mutex_lock(&rport->mutex);
+	__rport_fail_io_fast(rport);
+	mutex_unlock(&rport->mutex);
+}
+
+/**
+ * rport_dev_loss_timedout() - device loss timeout handler
+ */
+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 = rport_to_shost(rport);
+	struct srp_internal *i = to_srp_internal(shost->transportt);
+
+	pr_info("dev_loss_tmo expired for SRP %s / %s.\n",
+		dev_name(&rport->dev), dev_name(&shost->shost_gendev));
+
+	mutex_lock(&rport->mutex);
+	WARN_ON(srp_rport_set_state(rport, SRP_RPORT_LOST) != 0);
+	scsi_target_unblock(rport->dev.parent, SDEV_TRANSPORT_OFFLINE);
+	mutex_unlock(&rport->mutex);
+
+	i->f->rport_delete(rport);
+}
+
+static void __srp_start_tl_fail_timers(struct srp_rport *rport)
+{
+	struct Scsi_Host *shost = rport_to_shost(rport);
+	int fast_io_fail_tmo, dev_loss_tmo;
+
+	lockdep_assert_held(&rport->mutex);
+
+	if (!rport->deleted) {
+		fast_io_fail_tmo = rport->fast_io_fail_tmo;
+		dev_loss_tmo = rport->dev_loss_tmo;
+		pr_debug("%s current state: %d\n",
+			 dev_name(&shost->shost_gendev), rport->state);
+
+		if (fast_io_fail_tmo >= 0 &&
+		    srp_rport_set_state(rport, SRP_RPORT_BLOCKED) == 0) {
+			pr_debug("%s new state: %d\n",
+				 dev_name(&shost->shost_gendev),
+				 rport->state);
+			scsi_target_block(&shost->shost_gendev);
+			queue_delayed_work(system_long_wq,
+					   &rport->fast_io_fail_work,
+					   1UL * fast_io_fail_tmo * HZ);
+		}
+		if (dev_loss_tmo >= 0)
+			queue_delayed_work(system_long_wq,
+					   &rport->dev_loss_work,
+					   1UL * dev_loss_tmo * HZ);
+	} else {
+		pr_debug("%s has already been deleted\n",
+			 dev_name(&shost->shost_gendev));
+		srp_rport_set_state(rport, SRP_RPORT_FAIL_FAST);
+		scsi_target_unblock(&shost->shost_gendev,
+				    SDEV_TRANSPORT_OFFLINE);
+	}
+}
+
+/**
+ * srp_start_tl_fail_timers() - start the transport layer failure timers
+ *
+ * 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)
+{
+	mutex_lock(&rport->mutex);
+	__srp_start_tl_fail_timers(rport);
+	mutex_unlock(&rport->mutex);
+}
+EXPORT_SYMBOL(srp_start_tl_fail_timers);
+
+/**
+ * scsi_request_fn_active() - number of kernel threads inside scsi_request_fn()
+ */
+static int scsi_request_fn_active(struct Scsi_Host *shost)
+{
+	struct scsi_device *sdev;
+	struct request_queue *q;
+	int request_fn_active = 0;
+
+	shost_for_each_device(sdev, shost) {
+		q = sdev->request_queue;
+
+		spin_lock_irq(q->queue_lock);
+		request_fn_active += q->request_fn_active;
+		spin_unlock_irq(q->queue_lock);
+	}
+
+	return request_fn_active;
+}
+
+/**
+ * srp_reconnect_rport() - reconnect to an SRP target port
+ *
+ * Blocks SCSI command queueing before invoking reconnect() such that
+ * queuecommand() won't be invoked concurrently with reconnect() from outside
+ * the SCSI EH. This is important since a reconnect() implementation may
+ * reallocate resources needed by queuecommand().
+ *
+ * Notes:
+ * - This function neither waits until outstanding requests have finished nor
+ *   tries to abort these. It is the responsibility of the reconnect()
+ *   function to finish outstanding commands before reconnecting to the target
+ *   port.
+ * - It is the responsibility of the caller to ensure that the resources
+ *   reallocated by the reconnect() function won't be used while this function
+ *   is in progress. One possible strategy is to invoke this function from
+ *   the context of the SCSI EH thread only. Another possible strategy is to
+ *   lock the rport mutex inside each SCSI LLD callback that can be invoked by
+ *   the SCSI EH (the scsi_host_template.eh_*() functions and also the
+ *   scsi_host_template.queuecommand() function).
+ */
+int srp_reconnect_rport(struct srp_rport *rport)
+{
+	struct Scsi_Host *shost = rport_to_shost(rport);
+	struct srp_internal *i = to_srp_internal(shost->transportt);
+	struct scsi_device *sdev;
+	int res;
+
+	pr_debug("SCSI host %s\n", dev_name(&shost->shost_gendev));
+
+	res = mutex_lock_interruptible(&rport->mutex);
+	if (res)
+		goto out;
+	scsi_target_block(&shost->shost_gendev);
+	while (scsi_request_fn_active(shost))
+		msleep(20);
+	res = i->f->reconnect(rport);
+	pr_debug("%s (state %d): transport.reconnect() returned %d\n",
+		 dev_name(&shost->shost_gendev), rport->state, res);
+	if (res == 0) {
+		cancel_delayed_work(&rport->fast_io_fail_work);
+		cancel_delayed_work(&rport->dev_loss_work);
+
+		srp_rport_set_state(rport, SRP_RPORT_RUNNING);
+		scsi_target_unblock(&shost->shost_gendev, SDEV_RUNNING);
+		/*
+		 * If the SCSI error handler has offlined one or more devices,
+		 * invoking scsi_target_unblock() won't change the state of
+		 * these devices into running so do that explicitly.
+		 */
+		spin_lock_irq(shost->host_lock);
+		__shost_for_each_device(sdev, shost)
+			if (sdev->sdev_state == SDEV_OFFLINE)
+				sdev->sdev_state = SDEV_RUNNING;
+		spin_unlock_irq(shost->host_lock);
+	} else if (rport->state == SRP_RPORT_RUNNING) {
+		/*
+		 * srp_reconnect_rport() was invoked with fast_io_fail
+		 * off. Mark the port as failed and start the TL failure
+		 * timers if these had not yet been started.
+		 */
+		__rport_fail_io_fast(rport);
+		scsi_target_unblock(&shost->shost_gendev,
+				    SDEV_TRANSPORT_OFFLINE);
+		__srp_start_tl_fail_timers(rport);
+	} else if (rport->state != SRP_RPORT_BLOCKED) {
+		scsi_target_unblock(&shost->shost_gendev,
+				    SDEV_TRANSPORT_OFFLINE);
+	}
+	mutex_unlock(&rport->mutex);
+
+out:
+	return res;
+}
+EXPORT_SYMBOL(srp_reconnect_rport);
+
+/**
+ * srp_timed_out() - SRP transport intercept of the SCSI timeout EH
+ *
+ * If a timeout occurs while an rport is in the blocked state, ask the SCSI
+ * EH to continue waiting (BLK_EH_RESET_TIMER). Otherwise let the SCSI core
+ * handle the timeout (BLK_EH_NOT_HANDLED).
+ *
+ * Note: This function is called from soft-IRQ context and with the request
+ * queue lock held.
+ */
+static enum blk_eh_timer_return srp_timed_out(struct scsi_cmnd *scmd)
+{
+	struct scsi_device *sdev = scmd->device;
+	struct Scsi_Host *shost = sdev->host;
+	struct srp_internal *i = to_srp_internal(shost->transportt);
+
+	pr_debug("timeout for sdev %s\n", dev_name(&sdev->sdev_gendev));
+	return i->f->reset_timer_if_blocked && scsi_device_blocked(sdev) ?
+		BLK_EH_RESET_TIMER : BLK_EH_NOT_HANDLED;
+}
+
 static void srp_rport_release(struct device *dev)
 {
 	struct srp_rport *rport = dev_to_rport(dev);
 
+	cancel_delayed_work_sync(&rport->fast_io_fail_work);
+	cancel_delayed_work_sync(&rport->dev_loss_work);
+
 	put_device(dev->parent);
 	kfree(rport);
 }
@@ -214,12 +617,15 @@ struct srp_rport *srp_rport_add(struct Scsi_Host *shost,
 {
 	struct srp_rport *rport;
 	struct device *parent = &shost->shost_gendev;
+	struct srp_internal *i = to_srp_internal(shost->transportt);
 	int id, ret;
 
 	rport = kzalloc(sizeof(*rport), GFP_KERNEL);
 	if (!rport)
 		return ERR_PTR(-ENOMEM);
 
+	mutex_init(&rport->mutex);
+
 	device_initialize(&rport->dev);
 
 	rport->dev.parent = get_device(parent);
@@ -228,6 +634,13 @@ 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 = i->f->fast_io_fail_tmo ?
+		*i->f->fast_io_fail_tmo : 15;
+	rport->dev_loss_tmo = i->f->dev_loss_tmo ? *i->f->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);
 
@@ -277,6 +690,13 @@ void srp_rport_del(struct srp_rport *rport)
 	transport_remove_device(dev);
 	device_del(dev);
 	transport_destroy_device(dev);
+
+	mutex_lock(&rport->mutex);
+	if (rport->state == SRP_RPORT_BLOCKED)
+		__rport_fail_io_fast(rport);
+	rport->deleted = true;
+	mutex_unlock(&rport->mutex);
+
 	put_device(dev);
 }
 EXPORT_SYMBOL_GPL(srp_rport_del);
@@ -328,6 +748,8 @@ srp_attach_transport(struct srp_function_template *ft)
 	if (!i)
 		return NULL;
 
+	i->t.eh_timed_out = srp_timed_out;
+
 	i->t.tsk_mgmt_response = srp_tsk_mgmt_response;
 	i->t.it_nexus_response = srp_it_nexus_response;
 
@@ -345,6 +767,11 @@ 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->has_rport_state) {
+		i->rport_attrs[count++] = &dev_attr_state;
+		i->rport_attrs[count++] = &dev_attr_fast_io_fail_tmo;
+		i->rport_attrs[count++] = &dev_attr_dev_loss_tmo;
+	}
 	if (ft->rport_delete)
 		i->rport_attrs[count++] = &dev_attr_delete;
 	i->rport_attrs[count++] = NULL;
diff --git a/include/scsi/scsi_transport_srp.h b/include/scsi/scsi_transport_srp.h
index 5a2d2d1..ee70016 100644
--- a/include/scsi/scsi_transport_srp.h
+++ b/include/scsi/scsi_transport_srp.h
@@ -13,6 +13,26 @@ struct srp_rport_identifiers {
 	u8 roles;
 };
 
+/**
+ * enum srp_rport_state - SRP transport layer state
+ * @SRP_RPORT_RUNNING:   Transport layer operational.
+ * @SRP_RPORT_BLOCKED:   Transport layer not operational; fast I/O fail timer
+ *                       is running and I/O has been blocked.
+ * @SRP_RPORT_FAIL_FAST: Fast I/O fail timer has expired; fail I/O fast.
+ * @SRP_RPORT_LOST:      Device loss timer has expired; port is being removed.
+ */
+enum srp_rport_state {
+	SRP_RPORT_RUNNING,
+	SRP_RPORT_BLOCKED,
+	SRP_RPORT_FAIL_FAST,
+	SRP_RPORT_LOST,
+};
+
+/**
+ * struct srp_rport
+ * @lld_data: LLD private data.
+ * @mutex:    Protects against concurrent rport fast_io_fail / dev_loss_tmo.
+ */
 struct srp_rport {
 	/* for initiator and target drivers */
 
@@ -23,11 +43,38 @@ struct srp_rport {
 
 	/* for initiator drivers */
 
-	void *lld_data;	/* LLD private data */
+	void			*lld_data;
+
+	struct mutex		mutex;
+	enum srp_rport_state	state;
+	bool			deleted;
+	int			fast_io_fail_tmo;
+	int			dev_loss_tmo;
+	struct delayed_work	fast_io_fail_work;
+	struct delayed_work	dev_loss_work;
 };
 
+/**
+ * struct srp_function_template
+ * @has_rport_state: Whether or not to create the state, fast_io_fail_tmo and
+ *     dev_loss_tmo sysfs attribute for an rport.
+ * @reset_timer_if_blocked: Whether or srp_timed_out() should reset the command
+ *     timer if the device on which it has been queued is blocked.
+ * @fast_io_fail_tmo: If not NULL, points to the default fast_io_fail_tmo value.
+ * @dev_loss_tmo: If not NULL, points to the default dev_loss_tmo value.
+ * @reconnect: Callback function for reconnecting to the target. See also
+ *     srp_reconnect_rport().
+ * @terminate_rport_io: Callback function for terminating all outstanding I/O
+ *     requests for an rport.
+ */
 struct srp_function_template {
 	/* for initiator drivers */
+	bool has_rport_state;
+	bool reset_timer_if_blocked;
+	int *fast_io_fail_tmo;
+	int *dev_loss_tmo;
+	int (*reconnect)(struct srp_rport *rport);
+	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);
@@ -43,7 +90,30 @@ extern void srp_rport_put(struct srp_rport *rport);
 extern struct srp_rport *srp_rport_add(struct Scsi_Host *,
 				       struct srp_rport_identifiers *);
 extern void srp_rport_del(struct srp_rport *);
-
+extern int srp_tmo_valid(int fast_io_fail_tmo, int dev_loss_tmo);
+extern int srp_reconnect_rport(struct srp_rport *rport);
+extern void srp_start_tl_fail_timers(struct srp_rport *rport);
 extern void srp_remove_host(struct Scsi_Host *);
 
+/**
+ * srp_chkready() - evaluate the transport layer state before I/O
+ *
+ * Returns a SCSI result code that can be returned by the LLD queuecommand()
+ * implementation. The role of this function is similar to that of
+ * fc_remote_port_chkready().
+ */
+static inline int srp_chkready(struct srp_rport *rport)
+{
+	switch (rport->state) {
+	case SRP_RPORT_RUNNING:
+	case SRP_RPORT_BLOCKED:
+	default:
+		return 0;
+	case SRP_RPORT_FAIL_FAST:
+		return DID_TRANSPORT_FAILFAST << 16;
+	case SRP_RPORT_LOST:
+		return DID_NO_CONNECT << 16;
+	}
+}
+
 #endif
-- 
1.8.1.4

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[PATCH 04/10] IB/srp: Use SRP transport layer error recovery

[Bart Van Assche]

Enable fast_io_fail_tmo and dev_loss_tmo functionality for the IB
SRP initiator. Add kernel module parameters that allow to specify
default values for these parameters.

Signed-off-by: Bart Van Assche <bvanassche-HInyCGIudOg@public.gmane.org>
Acked-by: David Dillow <dillowda-1Heg1YXhbW8@public.gmane.org>
Cc: Roland Dreier <roland-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: Vu Pham <vu-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
Cc: Sebastian Riemer <sebastian.riemer-EIkl63zCoXaH+58JC4qpiA@public.gmane.org>
---
 drivers/infiniband/ulp/srp/ib_srp.c | 141 ++++++++++++++++++++++++++----------
 drivers/infiniband/ulp/srp/ib_srp.h |   1 -
 2 files changed, 101 insertions(+), 41 deletions(-)

diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index 414fd02..5551f3b 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -86,6 +86,27 @@ module_param(topspin_workarounds, int, 0444);
 MODULE_PARM_DESC(topspin_workarounds,
 		 "Enable workarounds for Topspin/Cisco SRP target bugs if != 0");
 
+static struct kernel_param_ops srp_tmo_ops;
+
+static int srp_fast_io_fail_tmo = 15;
+module_param_cb(fast_io_fail_tmo, &srp_tmo_ops, &srp_fast_io_fail_tmo,
+		S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(fast_io_fail_tmo,
+		 "Number of seconds between the observation of a transport"
+		 " layer error and failing all I/O. \"off\" means that this"
+		 " functionality is disabled.");
+
+static int srp_dev_loss_tmo = 60;
+module_param_cb(dev_loss_tmo, &srp_tmo_ops, &srp_dev_loss_tmo,
+		S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(dev_loss_tmo,
+		 "Maximum number of seconds that the SRP transport should"
+		 " insulate transport layer errors. After this time has been"
+		 " exceeded the SCSI host is removed. Should be"
+		 " between 1 and " __stringify(SCSI_DEVICE_BLOCK_MAX_TIMEOUT)
+		 " if fast_io_fail_tmo has not been set. \"off\" means that"
+		 " this functionality is disabled.");
+
 static void srp_add_one(struct ib_device *device);
 static void srp_remove_one(struct ib_device *device);
 static void srp_recv_completion(struct ib_cq *cq, void *target_ptr);
@@ -102,6 +123,44 @@ static struct ib_client srp_client = {
 
 static struct ib_sa_client srp_sa_client;
 
+static int srp_tmo_get(char *buffer, const struct kernel_param *kp)
+{
+	int tmo = *(int *)kp->arg;
+
+	if (tmo >= 0)
+		return sprintf(buffer, "%d", tmo);
+	else
+		return sprintf(buffer, "off");
+}
+
+static int srp_tmo_set(const char *val, const struct kernel_param *kp)
+{
+	int tmo, res;
+
+	if (strncmp(val, "off", 3) != 0) {
+		res = kstrtoint(val, 0, &tmo);
+		if (res)
+			goto out;
+	} else {
+		tmo = -1;
+	}
+	if (kp->arg == &srp_fast_io_fail_tmo)
+		res = srp_tmo_valid(tmo, srp_dev_loss_tmo);
+	else
+		res = srp_tmo_valid(srp_fast_io_fail_tmo, tmo);
+	if (res)
+		goto out;
+	*(int *)kp->arg = tmo;
+
+out:
+	return res;
+}
+
+static struct kernel_param_ops srp_tmo_ops = {
+	.get = srp_tmo_get,
+	.set = srp_tmo_set,
+};
+
 static inline struct srp_target_port *host_to_target(struct Scsi_Host *host)
 {
 	return (struct srp_target_port *) host->hostdata;
@@ -689,23 +748,42 @@ static void srp_free_req(struct srp_target_port *target,
 	spin_unlock_irqrestore(&target->lock, flags);
 }
 
-static void srp_reset_req(struct srp_target_port *target, struct srp_request *req)
+static void srp_finish_req(struct srp_target_port *target,
+			   struct srp_request *req, int result)
 {
 	struct scsi_cmnd *scmnd = srp_claim_req(target, req, NULL);
 
 	if (scmnd) {
 		srp_free_req(target, req, scmnd, 0);
-		scmnd->result = DID_RESET << 16;
+		scmnd->result = result;
 		scmnd->scsi_done(scmnd);
 	}
 }
 
-static int srp_reconnect_target(struct srp_target_port *target)
+static void srp_terminate_io(struct srp_rport *rport)
 {
-	struct Scsi_Host *shost = target->scsi_host;
-	int i, ret;
+	struct srp_target_port *target = rport->lld_data;
+	int i;
+
+	for (i = 0; i < SRP_CMD_SQ_SIZE; ++i) {
+		struct srp_request *req = &target->req_ring[i];
+		srp_finish_req(target, req, DID_TRANSPORT_FAILFAST << 16);
+	}
+}
 
-	scsi_target_block(&shost->shost_gendev);
+/*
+ * It is up to the caller to ensure that srp_rport_reconnect() calls are
+ * serialized and that no concurrent srp_queuecommand(), srp_abort(),
+ * srp_reset_device() or srp_reset_host() calls will occur while this function
+ * is in progress. One way to realize that is not to call this function
+ * directly but to call srp_reconnect_rport() instead since that last function
+ * serializes calls of this function via rport->mutex and also blocks
+ * srp_queuecommand() calls before invoking this function.
+ */
+static int srp_rport_reconnect(struct srp_rport *rport)
+{
+	struct srp_target_port *target = rport->lld_data;
+	int i, ret;
 
 	srp_disconnect_target(target);
 	/*
@@ -726,8 +804,7 @@ static int srp_reconnect_target(struct srp_target_port *target)
 
 	for (i = 0; i < SRP_CMD_SQ_SIZE; ++i) {
 		struct srp_request *req = &target->req_ring[i];
-		if (req->scmnd)
-			srp_reset_req(target, req);
+		srp_finish_req(target, req, DID_RESET << 16);
 	}
 
 	INIT_LIST_HEAD(&target->free_tx);
@@ -737,28 +814,9 @@ static int srp_reconnect_target(struct srp_target_port *target)
 	if (ret == 0)
 		ret = srp_connect_target(target);
 
-	scsi_target_unblock(&shost->shost_gendev, ret == 0 ? SDEV_RUNNING :
-			    SDEV_TRANSPORT_OFFLINE);
-	target->transport_offline = !!ret;
-
-	if (ret)
-		goto err;
-
-	shost_printk(KERN_INFO, target->scsi_host, PFX "reconnect succeeded\n");
-
-	return ret;
-
-err:
-	shost_printk(KERN_ERR, target->scsi_host,
-		     PFX "reconnect failed (%d), removing target port.\n", ret);
-
-	/*
-	 * We couldn't reconnect, so kill our target port off.
-	 * However, we have to defer the real removal because we
-	 * are in the context of the SCSI error handler now, which
-	 * will deadlock if we call scsi_remove_host().
-	 */
-	srp_queue_remove_work(target);
+	if (ret == 0)
+		shost_printk(KERN_INFO, target->scsi_host,
+			     PFX "reconnect succeeded\n");
 
 	return ret;
 }
@@ -1356,10 +1414,11 @@ static int srp_queuecommand(struct Scsi_Host *shost, struct scsi_cmnd *scmnd)
 	struct srp_cmd *cmd;
 	struct ib_device *dev;
 	unsigned long flags;
-	int len;
+	int len, result;
 
-	if (unlikely(target->transport_offline)) {
-		scmnd->result = DID_NO_CONNECT << 16;
+	result = srp_chkready(target->rport);
+	if (unlikely(result)) {
+		scmnd->result = result;
 		scmnd->scsi_done(scmnd);
 		return 0;
 	}
@@ -1757,7 +1816,7 @@ static int srp_abort(struct scsi_cmnd *scmnd)
 	if (srp_send_tsk_mgmt(target, req->index, scmnd->device->lun,
 			      SRP_TSK_ABORT_TASK) == 0)
 		ret = SUCCESS;
-	else if (target->transport_offline)
+	else if (target->rport->state == SRP_RPORT_LOST)
 		ret = FAST_IO_FAIL;
 	else
 		ret = FAILED;
@@ -1784,7 +1843,7 @@ static int srp_reset_device(struct scsi_cmnd *scmnd)
 	for (i = 0; i < SRP_CMD_SQ_SIZE; ++i) {
 		struct srp_request *req = &target->req_ring[i];
 		if (req->scmnd && req->scmnd->device == scmnd->device)
-			srp_reset_req(target, req);
+			srp_finish_req(target, req, DID_RESET << 16);
 	}
 
 	return SUCCESS;
@@ -1793,14 +1852,10 @@ static int srp_reset_device(struct scsi_cmnd *scmnd)
 static int srp_reset_host(struct scsi_cmnd *scmnd)
 {
 	struct srp_target_port *target = host_to_target(scmnd->device->host);
-	int ret = FAILED;
 
 	shost_printk(KERN_ERR, target->scsi_host, PFX "SRP reset_host called\n");
 
-	if (!srp_reconnect_target(target))
-		ret = SUCCESS;
-
-	return ret;
+	return srp_reconnect_rport(target->rport) == 0 ? SUCCESS : FAILED;
 }
 
 static int srp_slave_configure(struct scsi_device *sdev)
@@ -2637,7 +2692,13 @@ static void srp_remove_one(struct ib_device *device)
 }
 
 static struct srp_function_template ib_srp_transport_functions = {
+	.has_rport_state	 = true,
+	.reset_timer_if_blocked	 = true,
+	.fast_io_fail_tmo	 = &srp_fast_io_fail_tmo,
+	.dev_loss_tmo		 = &srp_dev_loss_tmo,
+	.reconnect		 = srp_rport_reconnect,
 	.rport_delete		 = srp_rport_delete,
+	.terminate_rport_io	 = srp_terminate_io,
 };
 
 static int __init srp_init_module(void)
diff --git a/drivers/infiniband/ulp/srp/ib_srp.h b/drivers/infiniband/ulp/srp/ib_srp.h
index 2a1768f..fd1817e 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.h
+++ b/drivers/infiniband/ulp/srp/ib_srp.h
@@ -140,7 +140,6 @@ struct srp_target_port {
 	unsigned int		cmd_sg_cnt;
 	unsigned int		indirect_size;
 	bool			allow_ext_sg;
-	bool			transport_offline;
 
 	/* Everything above this point is used in the hot path of
 	 * command processing. Try to keep them packed into cachelines.
-- 
1.8.1.4

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[PATCH 05/10] IB/srp: Start timers if a transport layer error occurs

[Bart Van Assche]

Start the reconnect timer, fast_io_fail timer and dev_loss timers
if a transport layer error occurs.

Signed-off-by: Bart Van Assche <bvanassche-HInyCGIudOg@public.gmane.org>
Acked-by: David Dillow <dillowda-1Heg1YXhbW8@public.gmane.org>
Cc: Roland Dreier <roland-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: Vu Pham <vu-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
Cc: Sebastian Riemer <sebastian.riemer-EIkl63zCoXaH+58JC4qpiA@public.gmane.org>
---
 drivers/infiniband/ulp/srp/ib_srp.c | 19 +++++++++++++++++++
 drivers/infiniband/ulp/srp/ib_srp.h |  1 +
 2 files changed, 20 insertions(+)

diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index 5551f3b..ceb84b6 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -593,6 +593,7 @@ static void srp_remove_target(struct srp_target_port *target)
 	srp_disconnect_target(target);
 	ib_destroy_cm_id(target->cm_id);
 	srp_free_target_ib(target);
+	cancel_work_sync(&target->tl_err_work);
 	srp_rport_put(target->rport);
 	srp_free_req_data(target);
 
@@ -1363,6 +1364,21 @@ static void srp_handle_recv(struct srp_target_port *target, struct ib_wc *wc)
 			     PFX "Recv failed with error code %d\n", res);
 }
 
+/**
+ * srp_tl_err_work() - handle a transport layer error
+ *
+ * Note: This function may get invoked before the rport has been created,
+ * hence the target->rport test.
+ */
+static void srp_tl_err_work(struct work_struct *work)
+{
+	struct srp_target_port *target;
+
+	target = container_of(work, struct srp_target_port, tl_err_work);
+	if (target->rport)
+		srp_start_tl_fail_timers(target->rport);
+}
+
 static void srp_handle_qp_err(enum ib_wc_status wc_status, bool send_err,
 			      struct srp_target_port *target)
 {
@@ -1371,6 +1387,7 @@ static void srp_handle_qp_err(enum ib_wc_status wc_status, bool send_err,
 			     PFX "failed %s status %d\n",
 			     send_err ? "send" : "receive",
 			     wc_status);
+		queue_work(system_long_wq, &target->tl_err_work);
 	}
 	target->qp_in_error = true;
 }
@@ -1733,6 +1750,7 @@ static int srp_cm_handler(struct ib_cm_id *cm_id, struct ib_cm_event *event)
 		if (ib_send_cm_drep(cm_id, NULL, 0))
 			shost_printk(KERN_ERR, target->scsi_host,
 				     PFX "Sending CM DREP failed\n");
+		queue_work(system_long_wq, &target->tl_err_work);
 		break;
 
 	case IB_CM_TIMEWAIT_EXIT:
@@ -2419,6 +2437,7 @@ static ssize_t srp_create_target(struct device *dev,
 			     sizeof (struct srp_indirect_buf) +
 			     target->cmd_sg_cnt * sizeof (struct srp_direct_buf);
 
+	INIT_WORK(&target->tl_err_work, srp_tl_err_work);
 	INIT_WORK(&target->remove_work, srp_remove_work);
 	spin_lock_init(&target->lock);
 	INIT_LIST_HEAD(&target->free_tx);
diff --git a/drivers/infiniband/ulp/srp/ib_srp.h b/drivers/infiniband/ulp/srp/ib_srp.h
index fd1817e..446b045 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.h
+++ b/drivers/infiniband/ulp/srp/ib_srp.h
@@ -177,6 +177,7 @@ struct srp_target_port {
 	struct srp_iu	       *rx_ring[SRP_RQ_SIZE];
 	struct srp_request	req_ring[SRP_CMD_SQ_SIZE];
 
+	struct work_struct	tl_err_work;
 	struct work_struct	remove_work;
 
 	struct list_head	list;
-- 
1.8.1.4

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[PATCH 06/10] scsi_transport_srp: Add periodic reconnect support

[Bart Van Assche]

Add support for periodically reconnecting to an SRP target until
the dev_loss timer expires. After the tenth reconnection attempt,
gradually slow down subsequent reconnect attempts.

Signed-off-by: Bart Van Assche <bvanassche-HInyCGIudOg@public.gmane.org>
Cc: David Dillow <dillowda-1Heg1YXhbW8@public.gmane.org>
Cc: Roland Dreier <roland-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: James Bottomley <JBottomley-MU7nAjRaF3makBO8gow8eQ@public.gmane.org>
Cc: Vu Pham <vu-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
Cc: Sebastian Riemer <sebastian.riemer-EIkl63zCoXaH+58JC4qpiA@public.gmane.org>
---
 drivers/scsi/scsi_transport_srp.c | 106 +++++++++++++++++++++++++++++++++++---
 include/scsi/scsi_transport_srp.h |  11 +++-
 2 files changed, 108 insertions(+), 9 deletions(-)

diff --git a/drivers/scsi/scsi_transport_srp.c b/drivers/scsi/scsi_transport_srp.c
index 675e203..04a97b6 100644
--- a/drivers/scsi/scsi_transport_srp.c
+++ b/drivers/scsi/scsi_transport_srp.c
@@ -41,7 +41,7 @@ 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 6
+#define SRP_RPORT_ATTRS 8
 
 struct srp_internal {
 	struct scsi_transport_template t;
@@ -69,11 +69,13 @@ static inline struct Scsi_Host *rport_to_shost(struct srp_rport *r)
  * are finished in a reasonable time. Hence do not allow the fast I/O fail
  * timeout to exceed SCSI_DEVICE_BLOCK_MAX_TIMEOUT. Furthermore, these
  * parameters must be such that multipath can detect failed paths timely.
- * Hence do not allow both parameters to be disabled simultaneously.
+ * Hence do not allow all three parameters to be disabled simultaneously.
  */
-int srp_tmo_valid(int fast_io_fail_tmo, int dev_loss_tmo)
+int srp_tmo_valid(int reconnect_delay, int fast_io_fail_tmo, int dev_loss_tmo)
 {
-	if (fast_io_fail_tmo < 0 && dev_loss_tmo < 0)
+	if (reconnect_delay < 0 && fast_io_fail_tmo < 0 && dev_loss_tmo < 0)
+		return -EINVAL;
+	if (reconnect_delay == 0)
 		return -EINVAL;
 	if (fast_io_fail_tmo > SCSI_DEVICE_BLOCK_MAX_TIMEOUT)
 		return -EINVAL;
@@ -202,6 +204,56 @@ static int srp_parse_tmo(int *tmo, const char *buf)
 	return res;
 }
 
+static ssize_t show_reconnect_delay(struct device *dev,
+				    struct device_attribute *attr, char *buf)
+{
+	struct srp_rport *rport = transport_class_to_srp_rport(dev);
+
+	return srp_show_tmo(buf, rport->reconnect_delay);
+}
+
+static ssize_t store_reconnect_delay(struct device *dev,
+				     struct device_attribute *attr,
+				     const char *buf, const size_t count)
+{
+	struct srp_rport *rport = transport_class_to_srp_rport(dev);
+	int res, delay;
+
+	res = srp_parse_tmo(&delay, buf);
+	if (res)
+		goto out;
+	res = srp_tmo_valid(delay, rport->fast_io_fail_tmo,
+			    rport->dev_loss_tmo);
+	if (res)
+		goto out;
+
+	if (rport->reconnect_delay <= 0 && delay > 0 &&
+	    rport->state != SRP_RPORT_RUNNING) {
+		queue_delayed_work(system_long_wq, &rport->reconnect_work,
+				   delay * HZ);
+	} else if (delay <= 0) {
+		cancel_delayed_work(&rport->reconnect_work);
+	}
+	rport->reconnect_delay = delay;
+	res = count;
+
+out:
+	return res;
+}
+
+static DEVICE_ATTR(reconnect_delay, S_IRUGO | S_IWUSR, show_reconnect_delay,
+		   store_reconnect_delay);
+
+static ssize_t show_failed_reconnects(struct device *dev,
+				      struct device_attribute *attr, char *buf)
+{
+	struct srp_rport *rport = transport_class_to_srp_rport(dev);
+
+	return sprintf(buf, "%d\n", rport->failed_reconnects);
+}
+
+static DEVICE_ATTR(failed_reconnects, S_IRUGO, show_failed_reconnects, NULL);
+
 static ssize_t show_srp_rport_fast_io_fail_tmo(struct device *dev,
 					       struct device_attribute *attr,
 					       char *buf)
@@ -222,7 +274,8 @@ static ssize_t store_srp_rport_fast_io_fail_tmo(struct device *dev,
 	res = srp_parse_tmo(&fast_io_fail_tmo, buf);
 	if (res)
 		goto out;
-	res = srp_tmo_valid(fast_io_fail_tmo, rport->dev_loss_tmo);
+	res = srp_tmo_valid(rport->reconnect_delay, fast_io_fail_tmo,
+			    rport->dev_loss_tmo);
 	if (res)
 		goto out;
 	rport->fast_io_fail_tmo = fast_io_fail_tmo;
@@ -256,7 +309,8 @@ static ssize_t store_srp_rport_dev_loss_tmo(struct device *dev,
 	res = srp_parse_tmo(&dev_loss_tmo, buf);
 	if (res)
 		goto out;
-	res = srp_tmo_valid(rport->fast_io_fail_tmo, dev_loss_tmo);
+	res = srp_tmo_valid(rport->reconnect_delay, rport->fast_io_fail_tmo,
+			    dev_loss_tmo);
 	if (res)
 		goto out;
 	rport->dev_loss_tmo = dev_loss_tmo;
@@ -312,6 +366,29 @@ invalid:
 	return -EINVAL;
 }
 
+/**
+ * srp_reconnect_work() - reconnect and schedule a new attempt if necessary
+ */
+static void srp_reconnect_work(struct work_struct *work)
+{
+	struct srp_rport *rport = container_of(to_delayed_work(work),
+					struct srp_rport, reconnect_work);
+	struct Scsi_Host *shost = rport_to_shost(rport);
+	int delay, res;
+
+	res = srp_reconnect_rport(rport);
+	if (res != 0) {
+		shost_printk(KERN_ERR, shost,
+			     "reconnect attempt %d failed (%d)\n",
+			     ++rport->failed_reconnects, res);
+		delay = rport->reconnect_delay *
+			min(100, max(1, rport->failed_reconnects - 10));
+		if (delay > 0)
+			queue_delayed_work(system_long_wq,
+					   &rport->reconnect_work, delay * HZ);
+	}
+}
+
 static void __rport_fail_io_fast(struct srp_rport *rport)
 {
 	struct Scsi_Host *shost = rport_to_shost(rport);
@@ -370,16 +447,21 @@ static void rport_dev_loss_timedout(struct work_struct *work)
 static void __srp_start_tl_fail_timers(struct srp_rport *rport)
 {
 	struct Scsi_Host *shost = rport_to_shost(rport);
-	int fast_io_fail_tmo, dev_loss_tmo;
+	int delay, fast_io_fail_tmo, dev_loss_tmo;
 
 	lockdep_assert_held(&rport->mutex);
 
 	if (!rport->deleted) {
+		delay = rport->reconnect_delay;
 		fast_io_fail_tmo = rport->fast_io_fail_tmo;
 		dev_loss_tmo = rport->dev_loss_tmo;
 		pr_debug("%s current state: %d\n",
 			 dev_name(&shost->shost_gendev), rport->state);
 
+		if (delay > 0)
+			queue_delayed_work(system_long_wq,
+					   &rport->reconnect_work,
+					   1UL * delay * HZ);
 		if (fast_io_fail_tmo >= 0 &&
 		    srp_rport_set_state(rport, SRP_RPORT_BLOCKED) == 0) {
 			pr_debug("%s new state: %d\n",
@@ -480,6 +562,7 @@ int srp_reconnect_rport(struct srp_rport *rport)
 		cancel_delayed_work(&rport->fast_io_fail_work);
 		cancel_delayed_work(&rport->dev_loss_work);
 
+		rport->failed_reconnects = 0;
 		srp_rport_set_state(rport, SRP_RPORT_RUNNING);
 		scsi_target_unblock(&shost->shost_gendev, SDEV_RUNNING);
 		/*
@@ -538,6 +621,7 @@ static void srp_rport_release(struct device *dev)
 {
 	struct srp_rport *rport = dev_to_rport(dev);
 
+	cancel_delayed_work_sync(&rport->reconnect_work);
 	cancel_delayed_work_sync(&rport->fast_io_fail_work);
 	cancel_delayed_work_sync(&rport->dev_loss_work);
 
@@ -634,6 +718,10 @@ 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;
 
+	if (i->f->reconnect)
+		rport->reconnect_delay = i->f->reconnect_delay ?
+			*i->f->reconnect_delay : 10;
+	INIT_DELAYED_WORK(&rport->reconnect_work, srp_reconnect_work);
 	rport->fast_io_fail_tmo = i->f->fast_io_fail_tmo ?
 		*i->f->fast_io_fail_tmo : 15;
 	rport->dev_loss_tmo = i->f->dev_loss_tmo ? *i->f->dev_loss_tmo : 60;
@@ -772,6 +860,10 @@ srp_attach_transport(struct srp_function_template *ft)
 		i->rport_attrs[count++] = &dev_attr_fast_io_fail_tmo;
 		i->rport_attrs[count++] = &dev_attr_dev_loss_tmo;
 	}
+	if (ft->reconnect) {
+		i->rport_attrs[count++] = &dev_attr_reconnect_delay;
+		i->rport_attrs[count++] = &dev_attr_failed_reconnects;
+	}
 	if (ft->rport_delete)
 		i->rport_attrs[count++] = &dev_attr_delete;
 	i->rport_attrs[count++] = NULL;
diff --git a/include/scsi/scsi_transport_srp.h b/include/scsi/scsi_transport_srp.h
index ee70016..4ebf691 100644
--- a/include/scsi/scsi_transport_srp.h
+++ b/include/scsi/scsi_transport_srp.h
@@ -31,7 +31,8 @@ enum srp_rport_state {
 /**
  * struct srp_rport
  * @lld_data: LLD private data.
- * @mutex:    Protects against concurrent rport fast_io_fail / dev_loss_tmo.
+ * @mutex:    Protects against concurrent rport reconnect / fast_io_fail /
+ *   dev_loss_tmo activity.
  */
 struct srp_rport {
 	/* for initiator and target drivers */
@@ -48,6 +49,9 @@ struct srp_rport {
 	struct mutex		mutex;
 	enum srp_rport_state	state;
 	bool			deleted;
+	int			reconnect_delay;
+	int			failed_reconnects;
+	struct delayed_work	reconnect_work;
 	int			fast_io_fail_tmo;
 	int			dev_loss_tmo;
 	struct delayed_work	fast_io_fail_work;
@@ -60,6 +64,7 @@ struct srp_rport {
  *     dev_loss_tmo sysfs attribute for an rport.
  * @reset_timer_if_blocked: Whether or srp_timed_out() should reset the command
  *     timer if the device on which it has been queued is blocked.
+ * @reconnect_delay: If not NULL, points to the default reconnect_delay value.
  * @fast_io_fail_tmo: If not NULL, points to the default fast_io_fail_tmo value.
  * @dev_loss_tmo: If not NULL, points to the default dev_loss_tmo value.
  * @reconnect: Callback function for reconnecting to the target. See also
@@ -71,6 +76,7 @@ struct srp_function_template {
 	/* for initiator drivers */
 	bool has_rport_state;
 	bool reset_timer_if_blocked;
+	int *reconnect_delay;
 	int *fast_io_fail_tmo;
 	int *dev_loss_tmo;
 	int (*reconnect)(struct srp_rport *rport);
@@ -90,7 +96,8 @@ extern void srp_rport_put(struct srp_rport *rport);
 extern struct srp_rport *srp_rport_add(struct Scsi_Host *,
 				       struct srp_rport_identifiers *);
 extern void srp_rport_del(struct srp_rport *);
-extern int srp_tmo_valid(int fast_io_fail_tmo, int dev_loss_tmo);
+extern int srp_tmo_valid(int reconnect_delay, int fast_io_fail_tmo,
+			 int dev_loss_tmo);
 extern int srp_reconnect_rport(struct srp_rport *rport);
 extern void srp_start_tl_fail_timers(struct srp_rport *rport);
 extern void srp_remove_host(struct Scsi_Host *);
-- 
1.8.1.4

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[PATCH 07/10] IB/srp: Add periodic reconnect functionality

[Bart Van Assche]

After a transport layer occurred, periodically try to reconnect
to the target until the dev_loss timer expires.  Protect the
callback functions that can be invoked from inside the SCSI EH
against concurrent invocation with srp_reconnect_rport() via the
rport mutex. Change the default dev_loss_tmo from 60s into 600s
to give the reconnect mechanism a chance to kick in.

Signed-off-by: Bart Van Assche <bvanassche-HInyCGIudOg@public.gmane.org>
Acked-by: David Dillow <dillowda-1Heg1YXhbW8@public.gmane.org>
Cc: Roland Dreier <roland-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: Vu Pham <vu-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
Cc: Sebastian Riemer <sebastian.riemer-EIkl63zCoXaH+58JC4qpiA@public.gmane.org>
---
 Documentation/ABI/stable/sysfs-transport-srp |  8 +++++
 drivers/infiniband/ulp/srp/ib_srp.c          | 52 ++++++++++++++++++++++++----
 2 files changed, 54 insertions(+), 6 deletions(-)

diff --git a/Documentation/ABI/stable/sysfs-transport-srp b/Documentation/ABI/stable/sysfs-transport-srp
index 178a44d..21bd480 100644
--- a/Documentation/ABI/stable/sysfs-transport-srp
+++ b/Documentation/ABI/stable/sysfs-transport-srp
@@ -30,6 +30,14 @@ Contact:	linux-scsi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
 Description:	16-byte local SRP port identifier in hexadecimal format. An
 		example: 4c:49:4e:55:58:20:56:49:4f:00:00:00:00:00:00:00.
 
+What:		/sys/class/srp_remote_ports/port-<h>:<n>/reconnect_delay
+Date:		December 1, 2013
+KernelVersion:	3.12
+Contact:	linux-scsi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
+Description:	Number of seconds the SCSI layer will wait after a reconnect
+		attempt failed before retrying. Setting this attribute to
+		"off" will disable time-based reconnecting.
+
 What:		/sys/class/srp_remote_ports/port-<h>:<n>/roles
 Date:		June 27, 2007
 KernelVersion:	2.6.24
diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index ceb84b6..4be3eb8 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -88,6 +88,11 @@ MODULE_PARM_DESC(topspin_workarounds,
 
 static struct kernel_param_ops srp_tmo_ops;
 
+static int srp_reconnect_delay = 10;
+module_param_cb(reconnect_delay, &srp_tmo_ops, &srp_reconnect_delay,
+		S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(reconnect_delay, "Time between successive reconnect attempts");
+
 static int srp_fast_io_fail_tmo = 15;
 module_param_cb(fast_io_fail_tmo, &srp_tmo_ops, &srp_fast_io_fail_tmo,
 		S_IRUGO | S_IWUSR);
@@ -96,7 +101,7 @@ MODULE_PARM_DESC(fast_io_fail_tmo,
 		 " layer error and failing all I/O. \"off\" means that this"
 		 " functionality is disabled.");
 
-static int srp_dev_loss_tmo = 60;
+static int srp_dev_loss_tmo = 600;
 module_param_cb(dev_loss_tmo, &srp_tmo_ops, &srp_dev_loss_tmo,
 		S_IRUGO | S_IWUSR);
 MODULE_PARM_DESC(dev_loss_tmo,
@@ -144,10 +149,14 @@ static int srp_tmo_set(const char *val, const struct kernel_param *kp)
 	} else {
 		tmo = -1;
 	}
-	if (kp->arg == &srp_fast_io_fail_tmo)
-		res = srp_tmo_valid(tmo, srp_dev_loss_tmo);
+	if (kp->arg == &srp_reconnect_delay)
+		res = srp_tmo_valid(tmo, srp_fast_io_fail_tmo,
+				    srp_dev_loss_tmo);
+	else if (kp->arg == &srp_fast_io_fail_tmo)
+		res = srp_tmo_valid(srp_reconnect_delay, tmo, srp_dev_loss_tmo);
 	else
-		res = srp_tmo_valid(srp_fast_io_fail_tmo, tmo);
+		res = srp_tmo_valid(srp_reconnect_delay, srp_fast_io_fail_tmo,
+				    tmo);
 	if (res)
 		goto out;
 	*(int *)kp->arg = tmo;
@@ -1426,18 +1435,29 @@ static void srp_send_completion(struct ib_cq *cq, void *target_ptr)
 static int srp_queuecommand(struct Scsi_Host *shost, struct scsi_cmnd *scmnd)
 {
 	struct srp_target_port *target = host_to_target(shost);
+	struct srp_rport *rport = target->rport;
 	struct srp_request *req;
 	struct srp_iu *iu;
 	struct srp_cmd *cmd;
 	struct ib_device *dev;
 	unsigned long flags;
 	int len, result;
+	const bool in_scsi_eh = !in_interrupt() && current == shost->ehandler;
+
+	/*
+	 * The SCSI EH thread is the only context from which srp_queuecommand()
+	 * can get invoked for blocked devices (SDEV_BLOCK /
+	 * SDEV_CREATED_BLOCK). Avoid racing with srp_reconnect_rport() by
+	 * locking the rport mutex if invoked from inside the SCSI EH.
+	 */
+	if (in_scsi_eh)
+		mutex_lock(&rport->mutex);
 
 	result = srp_chkready(target->rport);
 	if (unlikely(result)) {
 		scmnd->result = result;
 		scmnd->scsi_done(scmnd);
-		return 0;
+		goto unlock_rport;
 	}
 
 	spin_lock_irqsave(&target->lock, flags);
@@ -1482,6 +1502,10 @@ static int srp_queuecommand(struct Scsi_Host *shost, struct scsi_cmnd *scmnd)
 		goto err_unmap;
 	}
 
+unlock_rport:
+	if (in_scsi_eh)
+		mutex_unlock(&rport->mutex);
+
 	return 0;
 
 err_unmap:
@@ -1496,6 +1520,9 @@ err_iu:
 err_unlock:
 	spin_unlock_irqrestore(&target->lock, flags);
 
+	if (in_scsi_eh)
+		mutex_unlock(&rport->mutex);
+
 	return SCSI_MLQUEUE_HOST_BUSY;
 }
 
@@ -1780,6 +1807,7 @@ static int srp_cm_handler(struct ib_cm_id *cm_id, struct ib_cm_event *event)
 static int srp_send_tsk_mgmt(struct srp_target_port *target,
 			     u64 req_tag, unsigned int lun, u8 func)
 {
+	struct srp_rport *rport = target->rport;
 	struct ib_device *dev = target->srp_host->srp_dev->dev;
 	struct srp_iu *iu;
 	struct srp_tsk_mgmt *tsk_mgmt;
@@ -1789,12 +1817,20 @@ static int srp_send_tsk_mgmt(struct srp_target_port *target,
 
 	init_completion(&target->tsk_mgmt_done);
 
+	/*
+	 * Lock the rport mutex to avoid that srp_create_target_ib() is
+	 * invoked while a task management function is being sent.
+	 */
+	mutex_lock(&rport->mutex);
 	spin_lock_irq(&target->lock);
 	iu = __srp_get_tx_iu(target, SRP_IU_TSK_MGMT);
 	spin_unlock_irq(&target->lock);
 
-	if (!iu)
+	if (!iu) {
+		mutex_unlock(&rport->mutex);
+
 		return -1;
+	}
 
 	ib_dma_sync_single_for_cpu(dev, iu->dma, sizeof *tsk_mgmt,
 				   DMA_TO_DEVICE);
@@ -1811,8 +1847,11 @@ static int srp_send_tsk_mgmt(struct srp_target_port *target,
 				      DMA_TO_DEVICE);
 	if (srp_post_send(target, iu, sizeof *tsk_mgmt)) {
 		srp_put_tx_iu(target, iu, SRP_IU_TSK_MGMT);
+		mutex_unlock(&rport->mutex);
+
 		return -1;
 	}
+	mutex_unlock(&rport->mutex);
 
 	if (!wait_for_completion_timeout(&target->tsk_mgmt_done,
 					 msecs_to_jiffies(SRP_ABORT_TIMEOUT_MS)))
@@ -2713,6 +2752,7 @@ static void srp_remove_one(struct ib_device *device)
 static struct srp_function_template ib_srp_transport_functions = {
 	.has_rport_state	 = true,
 	.reset_timer_if_blocked	 = true,
+	.reconnect_delay	 = &srp_reconnect_delay,
 	.fast_io_fail_tmo	 = &srp_fast_io_fail_tmo,
 	.dev_loss_tmo		 = &srp_dev_loss_tmo,
 	.reconnect		 = srp_rport_reconnect,
-- 
1.8.1.4

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[PATCH 08/10] IB/srp: Export sgid to sysfs

[Bart Van Assche]

On an initiator system with multiple IB ports it is not yet possible
to figure out what the originating port of an SRP connection is. Hence
make the source GID available in sysfs.

Signed-off-by: Bart Van Assche <bvanassche-HInyCGIudOg@public.gmane.org>
Cc: David Dillow <dillowda-1Heg1YXhbW8@public.gmane.org>
Cc: Roland Dreier <roland-BHEL68pLQRGGvPXPguhicg@public.gmane.org>
Cc: Vu Pham <vu-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
Cc: Sebastian Riemer <sebastian.riemer-EIkl63zCoXaH+58JC4qpiA@public.gmane.org>
---
 Documentation/ABI/stable/sysfs-driver-ib_srp |  7 +++++++
 drivers/infiniband/ulp/srp/ib_srp.c          | 10 ++++++++++
 2 files changed, 17 insertions(+)

diff --git a/Documentation/ABI/stable/sysfs-driver-ib_srp b/Documentation/ABI/stable/sysfs-driver-ib_srp
index 18e9b27..ab8efd5 100644
--- a/Documentation/ABI/stable/sysfs-driver-ib_srp
+++ b/Documentation/ABI/stable/sysfs-driver-ib_srp
@@ -155,6 +155,13 @@ Contact:	linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
 Description:	InfiniBand service ID used for establishing communication with
 		the SRP	target.
 
+What:		/sys/class/scsi_host/host<n>/sgid
+Date:		December 1, 2013
+KernelVersion:	3.12
+Contact:	linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
+Description:	InfiniBand GID of the source port used for communication with
+		the SRP target.
+
 What:		/sys/class/scsi_host/host<n>/zero_req_lim
 Date:		September 20, 2006
 KernelVersion:	2.6.18
diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index 4be3eb8..da60d11 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -1965,6 +1965,14 @@ static ssize_t show_pkey(struct device *dev, struct device_attribute *attr,
 	return sprintf(buf, "0x%04x\n", be16_to_cpu(target->path.pkey));
 }
 
+static ssize_t show_sgid(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct srp_target_port *target = host_to_target(class_to_shost(dev));
+
+	return sprintf(buf, "%pI6\n", target->path.sgid.raw);
+}
+
 static ssize_t show_dgid(struct device *dev, struct device_attribute *attr,
 			 char *buf)
 {
@@ -2049,6 +2057,7 @@ static DEVICE_ATTR(id_ext,	    S_IRUGO, show_id_ext,	   NULL);
 static DEVICE_ATTR(ioc_guid,	    S_IRUGO, show_ioc_guid,	   NULL);
 static DEVICE_ATTR(service_id,	    S_IRUGO, show_service_id,	   NULL);
 static DEVICE_ATTR(pkey,	    S_IRUGO, show_pkey,		   NULL);
+static DEVICE_ATTR(sgid,	    S_IRUGO, show_sgid,		   NULL);
 static DEVICE_ATTR(dgid,	    S_IRUGO, show_dgid,		   NULL);
 static DEVICE_ATTR(orig_dgid,	    S_IRUGO, show_orig_dgid,	   NULL);
 static DEVICE_ATTR(req_lim,         S_IRUGO, show_req_lim,         NULL);
@@ -2065,6 +2074,7 @@ static struct device_attribute *srp_host_attrs[] = {
 	&dev_attr_ioc_guid,
 	&dev_attr_service_id,
 	&dev_attr_pkey,
+	&dev_attr_sgid,
 	&dev_attr_dgid,
 	&dev_attr_orig_dgid,
 	&dev_attr_req_lim,
-- 
1.8.1.4

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[PATCH 09/10] IB/srp: Introduce srp_alloc_req_data()

[Bart Van Assche]

This patch does not change any functionality.

Signed-off-by: Bart Van Assche <bvanassche-HInyCGIudOg@public.gmane.org>
Cc: David Dillow <dillowda-1Heg1YXhbW8@public.gmane.org>
Cc: Roland Dreier <roland-BHEL68pLQRGGvPXPguhicg@public.gmane.org>
Cc: Vu Pham <vu-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
Cc: Sebastian Riemer <sebastian.riemer-EIkl63zCoXaH+58JC4qpiA@public.gmane.org>
---
 drivers/infiniband/ulp/srp/ib_srp.c | 64 +++++++++++++++++++++++--------------
 1 file changed, 40 insertions(+), 24 deletions(-)

diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index da60d11..fdc0bc1 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -576,6 +576,42 @@ static void srp_free_req_data(struct srp_target_port *target)
 	}
 }
 
+static int srp_alloc_req_data(struct srp_target_port *target)
+{
+	struct srp_device *srp_dev = target->srp_host->srp_dev;
+	struct ib_device *ibdev = srp_dev->dev;
+	struct srp_request *req;
+	dma_addr_t dma_addr;
+	int i, ret = -ENOMEM;
+
+	INIT_LIST_HEAD(&target->free_reqs);
+
+	for (i = 0; i < SRP_CMD_SQ_SIZE; ++i) {
+		req = &target->req_ring[i];
+		req->fmr_list = kmalloc(target->cmd_sg_cnt * sizeof(void *),
+					GFP_KERNEL);
+		req->map_page = kmalloc(SRP_FMR_SIZE * sizeof(void *),
+					GFP_KERNEL);
+		req->indirect_desc = kmalloc(target->indirect_size, GFP_KERNEL);
+		if (!req->fmr_list || !req->map_page || !req->indirect_desc)
+			goto out;
+
+		dma_addr = ib_dma_map_single(ibdev, req->indirect_desc,
+					     target->indirect_size,
+					     DMA_TO_DEVICE);
+		if (ib_dma_mapping_error(ibdev, dma_addr))
+			goto out;
+
+		req->indirect_dma_addr = dma_addr;
+		req->index = i;
+		list_add_tail(&req->list, &target->free_reqs);
+	}
+	ret = 0;
+
+out:
+	return ret;
+}
+
 /**
  * srp_del_scsi_host_attr() - Remove attributes defined in the host template.
  * @shost: SCSI host whose attributes to remove from sysfs.
@@ -2433,8 +2469,7 @@ static ssize_t srp_create_target(struct device *dev,
 	struct Scsi_Host *target_host;
 	struct srp_target_port *target;
 	struct ib_device *ibdev = host->srp_dev->dev;
-	dma_addr_t dma_addr;
-	int i, ret;
+	int ret;
 
 	target_host = scsi_host_alloc(&srp_template,
 				      sizeof (struct srp_target_port));
@@ -2490,28 +2525,9 @@ static ssize_t srp_create_target(struct device *dev,
 	INIT_WORK(&target->remove_work, srp_remove_work);
 	spin_lock_init(&target->lock);
 	INIT_LIST_HEAD(&target->free_tx);
-	INIT_LIST_HEAD(&target->free_reqs);
-	for (i = 0; i < SRP_CMD_SQ_SIZE; ++i) {
-		struct srp_request *req = &target->req_ring[i];
-
-		req->fmr_list = kmalloc(target->cmd_sg_cnt * sizeof (void *),
-					GFP_KERNEL);
-		req->map_page = kmalloc(SRP_FMR_SIZE * sizeof (void *),
-					GFP_KERNEL);
-		req->indirect_desc = kmalloc(target->indirect_size, GFP_KERNEL);
-		if (!req->fmr_list || !req->map_page || !req->indirect_desc)
-			goto err_free_mem;
-
-		dma_addr = ib_dma_map_single(ibdev, req->indirect_desc,
-					     target->indirect_size,
-					     DMA_TO_DEVICE);
-		if (ib_dma_mapping_error(ibdev, dma_addr))
-			goto err_free_mem;
-
-		req->indirect_dma_addr = dma_addr;
-		req->index = i;
-		list_add_tail(&req->list, &target->free_reqs);
-	}
+	ret = srp_alloc_req_data(target);
+	if (ret)
+		goto err_free_mem;
 
 	ib_query_gid(ibdev, host->port, 0, &target->path.sgid);
 
-- 
1.8.1.4

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[PATCH 10/10] IB/srp: Make queue size configurable

[Bart Van Assche]

Certain storage configurations, e.g. a sufficiently large array of
hard disks in a RAID configuration, need a queue depth above 64 to
achieve optimal performance. Hence make the queue depth configurable.

Signed-off-by: Bart Van Assche <bvanassche-HInyCGIudOg@public.gmane.org>
Cc: David Dillow <dillowda-1Heg1YXhbW8@public.gmane.org>
Cc: Roland Dreier <roland-BHEL68pLQRGGvPXPguhicg@public.gmane.org>
Cc: Vu Pham <vu-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
Cc: Sebastian Riemer <sebastian.riemer-EIkl63zCoXaH+58JC4qpiA@public.gmane.org>
Cc: Konrad Grzybowski <konrad.grzybowski-XLFqaoR9dsI@public.gmane.org>
---
 drivers/infiniband/ulp/srp/ib_srp.c | 125 +++++++++++++++++++++++++++---------
 drivers/infiniband/ulp/srp/ib_srp.h |  17 +++--
 2 files changed, 103 insertions(+), 39 deletions(-)

diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index fdc0bc1..b0a37ff 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -299,16 +299,16 @@ static int srp_create_target_ib(struct srp_target_port *target)
 		return -ENOMEM;
 
 	recv_cq = ib_create_cq(target->srp_host->srp_dev->dev,
-			       srp_recv_completion, NULL, target, SRP_RQ_SIZE,
-			       target->comp_vector);
+			       srp_recv_completion, NULL, target,
+			       target->queue_size, target->comp_vector);
 	if (IS_ERR(recv_cq)) {
 		ret = PTR_ERR(recv_cq);
 		goto err;
 	}
 
 	send_cq = ib_create_cq(target->srp_host->srp_dev->dev,
-			       srp_send_completion, NULL, target, SRP_SQ_SIZE,
-			       target->comp_vector);
+			       srp_send_completion, NULL, target,
+			       target->queue_size, target->comp_vector);
 	if (IS_ERR(send_cq)) {
 		ret = PTR_ERR(send_cq);
 		goto err_recv_cq;
@@ -317,8 +317,8 @@ static int srp_create_target_ib(struct srp_target_port *target)
 	ib_req_notify_cq(recv_cq, IB_CQ_NEXT_COMP);
 
 	init_attr->event_handler       = srp_qp_event;
-	init_attr->cap.max_send_wr     = SRP_SQ_SIZE;
-	init_attr->cap.max_recv_wr     = SRP_RQ_SIZE;
+	init_attr->cap.max_send_wr     = target->queue_size;
+	init_attr->cap.max_recv_wr     = target->queue_size;
 	init_attr->cap.max_recv_sge    = 1;
 	init_attr->cap.max_send_sge    = 1;
 	init_attr->sq_sig_type         = IB_SIGNAL_ALL_WR;
@@ -364,6 +364,10 @@ err:
 	return ret;
 }
 
+/*
+ * Note: this function may be called without srp_alloc_iu_bufs() having been
+ * invoked. Hence the target->[rt]x_ring checks.
+ */
 static void srp_free_target_ib(struct srp_target_port *target)
 {
 	int i;
@@ -375,10 +379,18 @@ static void srp_free_target_ib(struct srp_target_port *target)
 	target->qp = NULL;
 	target->send_cq = target->recv_cq = NULL;
 
-	for (i = 0; i < SRP_RQ_SIZE; ++i)
-		srp_free_iu(target->srp_host, target->rx_ring[i]);
-	for (i = 0; i < SRP_SQ_SIZE; ++i)
-		srp_free_iu(target->srp_host, target->tx_ring[i]);
+	if (target->rx_ring) {
+		for (i = 0; i < target->queue_size; ++i)
+			srp_free_iu(target->srp_host, target->rx_ring[i]);
+		kfree(target->rx_ring);
+		target->rx_ring = NULL;
+	}
+	if (target->tx_ring) {
+		for (i = 0; i < target->queue_size; ++i)
+			srp_free_iu(target->srp_host, target->tx_ring[i]);
+		kfree(target->tx_ring);
+		target->tx_ring = NULL;
+	}
 }
 
 static void srp_path_rec_completion(int status,
@@ -564,7 +576,11 @@ static void srp_free_req_data(struct srp_target_port *target)
 	struct srp_request *req;
 	int i;
 
-	for (i = 0, req = target->req_ring; i < SRP_CMD_SQ_SIZE; ++i, ++req) {
+	if (!target->req_ring)
+		return;
+
+	for (i = 0; i < target->req_ring_size; ++i) {
+		req = &target->req_ring[i];
 		kfree(req->fmr_list);
 		kfree(req->map_page);
 		if (req->indirect_dma_addr) {
@@ -574,6 +590,9 @@ static void srp_free_req_data(struct srp_target_port *target)
 		}
 		kfree(req->indirect_desc);
 	}
+
+	kfree(target->req_ring);
+	target->req_ring = NULL;
 }
 
 static int srp_alloc_req_data(struct srp_target_port *target)
@@ -586,7 +605,12 @@ static int srp_alloc_req_data(struct srp_target_port *target)
 
 	INIT_LIST_HEAD(&target->free_reqs);
 
-	for (i = 0; i < SRP_CMD_SQ_SIZE; ++i) {
+	target->req_ring = kzalloc(target->req_ring_size *
+				   sizeof(*target->req_ring), GFP_KERNEL);
+	if (!target->req_ring)
+		goto out;
+
+	for (i = 0; i < target->req_ring_size; ++i) {
 		req = &target->req_ring[i];
 		req->fmr_list = kmalloc(target->cmd_sg_cnt * sizeof(void *),
 					GFP_KERNEL);
@@ -811,7 +835,7 @@ static void srp_terminate_io(struct srp_rport *rport)
 	struct srp_target_port *target = rport->lld_data;
 	int i;
 
-	for (i = 0; i < SRP_CMD_SQ_SIZE; ++i) {
+	for (i = 0; i < target->req_ring_size; ++i) {
 		struct srp_request *req = &target->req_ring[i];
 		srp_finish_req(target, req, DID_TRANSPORT_FAILFAST << 16);
 	}
@@ -848,13 +872,13 @@ static int srp_rport_reconnect(struct srp_rport *rport)
 	else
 		srp_create_target_ib(target);
 
-	for (i = 0; i < SRP_CMD_SQ_SIZE; ++i) {
+	for (i = 0; i < target->req_ring_size; ++i) {
 		struct srp_request *req = &target->req_ring[i];
 		srp_finish_req(target, req, DID_RESET << 16);
 	}
 
 	INIT_LIST_HEAD(&target->free_tx);
-	for (i = 0; i < SRP_SQ_SIZE; ++i)
+	for (i = 0; i < target->queue_size; ++i)
 		list_add(&target->tx_ring[i]->list, &target->free_tx);
 
 	if (ret == 0)
@@ -1562,11 +1586,24 @@ err_unlock:
 	return SCSI_MLQUEUE_HOST_BUSY;
 }
 
+/*
+ * Note: the resources allocated in this function are freed in
+ * srp_free_target_ib().
+ */
 static int srp_alloc_iu_bufs(struct srp_target_port *target)
 {
 	int i;
 
-	for (i = 0; i < SRP_RQ_SIZE; ++i) {
+	target->rx_ring = kzalloc(target->queue_size * sizeof(*target->rx_ring),
+				  GFP_KERNEL);
+	if (!target->rx_ring)
+		goto err_no_ring;
+	target->tx_ring = kzalloc(target->queue_size * sizeof(*target->tx_ring),
+				  GFP_KERNEL);
+	if (!target->tx_ring)
+		goto err_no_ring;
+
+	for (i = 0; i < target->queue_size; ++i) {
 		target->rx_ring[i] = srp_alloc_iu(target->srp_host,
 						  target->max_ti_iu_len,
 						  GFP_KERNEL, DMA_FROM_DEVICE);
@@ -1574,7 +1611,7 @@ static int srp_alloc_iu_bufs(struct srp_target_port *target)
 			goto err;
 	}
 
-	for (i = 0; i < SRP_SQ_SIZE; ++i) {
+	for (i = 0; i < target->queue_size; ++i) {
 		target->tx_ring[i] = srp_alloc_iu(target->srp_host,
 						  target->max_iu_len,
 						  GFP_KERNEL, DMA_TO_DEVICE);
@@ -1587,16 +1624,18 @@ static int srp_alloc_iu_bufs(struct srp_target_port *target)
 	return 0;
 
 err:
-	for (i = 0; i < SRP_RQ_SIZE; ++i) {
+	for (i = 0; i < target->queue_size; ++i) {
 		srp_free_iu(target->srp_host, target->rx_ring[i]);
-		target->rx_ring[i] = NULL;
-	}
-
-	for (i = 0; i < SRP_SQ_SIZE; ++i) {
 		srp_free_iu(target->srp_host, target->tx_ring[i]);
-		target->tx_ring[i] = NULL;
 	}
 
+
+err_no_ring:
+	kfree(target->tx_ring);
+	target->tx_ring = NULL;
+	kfree(target->rx_ring);
+	target->rx_ring = NULL;
+
 	return -ENOMEM;
 }
 
@@ -1647,6 +1686,9 @@ static void srp_cm_rep_handler(struct ib_cm_id *cm_id,
 		target->scsi_host->can_queue
 			= min(target->req_lim - SRP_TSK_MGMT_SQ_SIZE,
 			      target->scsi_host->can_queue);
+		target->scsi_host->cmd_per_lun
+			= min_t(int, target->scsi_host->can_queue,
+				target->scsi_host->cmd_per_lun);
 	} else {
 		shost_printk(KERN_WARNING, target->scsi_host,
 			     PFX "Unhandled RSP opcode %#x\n", lrsp->opcode);
@@ -1654,7 +1696,7 @@ static void srp_cm_rep_handler(struct ib_cm_id *cm_id,
 		goto error;
 	}
 
-	if (!target->rx_ring[0]) {
+	if (!target->rx_ring) {
 		ret = srp_alloc_iu_bufs(target);
 		if (ret)
 			goto error;
@@ -1674,7 +1716,7 @@ static void srp_cm_rep_handler(struct ib_cm_id *cm_id,
 	if (ret)
 		goto error_free;
 
-	for (i = 0; i < SRP_RQ_SIZE; i++) {
+	for (i = 0; i < target->queue_size; i++) {
 		struct srp_iu *iu = target->rx_ring[i];
 		ret = srp_post_recv(target, iu);
 		if (ret)
@@ -1933,7 +1975,7 @@ static int srp_reset_device(struct scsi_cmnd *scmnd)
 	if (target->tsk_mgmt_status)
 		return FAILED;
 
-	for (i = 0; i < SRP_CMD_SQ_SIZE; ++i) {
+	for (i = 0; i < target->req_ring_size; ++i) {
 		struct srp_request *req = &target->req_ring[i];
 		if (req->scmnd && req->scmnd->device == scmnd->device)
 			srp_finish_req(target, req, DID_RESET << 16);
@@ -2136,9 +2178,9 @@ static struct scsi_host_template srp_template = {
 	.eh_host_reset_handler		= srp_reset_host,
 	.skip_settle_delay		= true,
 	.sg_tablesize			= SRP_DEF_SG_TABLESIZE,
-	.can_queue			= SRP_CMD_SQ_SIZE,
+	.can_queue			= SRP_DEFAULT_CMD_SQ_SIZE,
 	.this_id			= -1,
-	.cmd_per_lun			= SRP_CMD_SQ_SIZE,
+	.cmd_per_lun			= SRP_DEFAULT_CMD_SQ_SIZE,
 	.use_clustering			= ENABLE_CLUSTERING,
 	.shost_attrs			= srp_host_attrs
 };
@@ -2245,6 +2287,7 @@ enum {
 	SRP_OPT_SG_TABLESIZE	= 1 << 11,
 	SRP_OPT_COMP_VECTOR	= 1 << 12,
 	SRP_OPT_TL_RETRY_COUNT	= 1 << 13,
+	SRP_OPT_CAN_QUEUE	= 1 << 14,
 	SRP_OPT_ALL		= (SRP_OPT_ID_EXT	|
 				   SRP_OPT_IOC_GUID	|
 				   SRP_OPT_DGID		|
@@ -2267,6 +2310,7 @@ static const match_table_t srp_opt_tokens = {
 	{ SRP_OPT_SG_TABLESIZE,		"sg_tablesize=%u"	},
 	{ SRP_OPT_COMP_VECTOR,		"comp_vector=%u"	},
 	{ SRP_OPT_TL_RETRY_COUNT,	"tl_retry_count=%u"	},
+	{ SRP_OPT_CAN_QUEUE,		"can_queue=%d"		},
 	{ SRP_OPT_ERR,			NULL 			}
 };
 
@@ -2361,13 +2405,25 @@ static int srp_parse_options(const char *buf, struct srp_target_port *target)
 			target->scsi_host->max_sectors = token;
 			break;
 
+		case SRP_OPT_CAN_QUEUE:
+			if (match_int(args, &token) || token < 1) {
+				pr_warn("bad can_queue parameter '%s'\n", p);
+				goto out;
+			}
+			target->scsi_host->can_queue = token;
+			target->queue_size = token + SRP_RSP_SQ_SIZE +
+					     SRP_TSK_MGMT_SQ_SIZE;
+			if (!(opt_mask & SRP_OPT_MAX_CMD_PER_LUN))
+				target->scsi_host->cmd_per_lun = token;
+			break;
+
 		case SRP_OPT_MAX_CMD_PER_LUN:
-			if (match_int(args, &token)) {
+			if (match_int(args, &token) || token < 1) {
 				pr_warn("bad max cmd_per_lun parameter '%s'\n",
 					p);
 				goto out;
 			}
-			target->scsi_host->cmd_per_lun = min(token, SRP_CMD_SQ_SIZE);
+			target->scsi_host->cmd_per_lun = token;
 			break;
 
 		case SRP_OPT_IO_CLASS:
@@ -2455,6 +2511,12 @@ static int srp_parse_options(const char *buf, struct srp_target_port *target)
 				pr_warn("target creation request is missing parameter '%s'\n",
 					srp_opt_tokens[i].pattern);
 
+	if (target->scsi_host->cmd_per_lun > target->scsi_host->can_queue
+	    && (opt_mask & SRP_OPT_MAX_CMD_PER_LUN))
+		pr_warn("cmd_per_lun = %d > can_queue = %d\n",
+			target->scsi_host->cmd_per_lun,
+			target->scsi_host->can_queue);
+
 out:
 	kfree(options);
 	return ret;
@@ -2493,11 +2555,14 @@ static ssize_t srp_create_target(struct device *dev,
 	target->sg_tablesize	= indirect_sg_entries ? : cmd_sg_entries;
 	target->allow_ext_sg	= allow_ext_sg;
 	target->tl_retry_count	= 7;
+	target->queue_size	= SRP_DEFAULT_QUEUE_SIZE;
 
 	ret = srp_parse_options(buf, target);
 	if (ret)
 		goto err;
 
+	target->req_ring_size = target->queue_size - SRP_TSK_MGMT_SQ_SIZE;
+
 	if (!srp_conn_unique(target->srp_host, target)) {
 		shost_printk(KERN_INFO, target->scsi_host,
 			     PFX "Already connected to target port with id_ext=%016llx;ioc_guid=%016llx;initiator_ext=%016llx\n",
diff --git a/drivers/infiniband/ulp/srp/ib_srp.h b/drivers/infiniband/ulp/srp/ib_srp.h
index 446b045..5756810 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.h
+++ b/drivers/infiniband/ulp/srp/ib_srp.h
@@ -57,14 +57,11 @@ enum {
 	SRP_MAX_LUN		= 512,
 	SRP_DEF_SG_TABLESIZE	= 12,
 
-	SRP_RQ_SHIFT    	= 6,
-	SRP_RQ_SIZE		= 1 << SRP_RQ_SHIFT,
-
-	SRP_SQ_SIZE		= SRP_RQ_SIZE,
+	SRP_DEFAULT_QUEUE_SIZE	= 1 << 6,
 	SRP_RSP_SQ_SIZE		= 1,
-	SRP_REQ_SQ_SIZE		= SRP_SQ_SIZE - SRP_RSP_SQ_SIZE,
 	SRP_TSK_MGMT_SQ_SIZE	= 1,
-	SRP_CMD_SQ_SIZE		= SRP_REQ_SQ_SIZE - SRP_TSK_MGMT_SQ_SIZE,
+	SRP_DEFAULT_CMD_SQ_SIZE = SRP_DEFAULT_QUEUE_SIZE - SRP_RSP_SQ_SIZE -
+				  SRP_TSK_MGMT_SQ_SIZE,
 
 	SRP_TAG_NO_REQ		= ~0U,
 	SRP_TAG_TSK_MGMT	= 1U << 31,
@@ -156,6 +153,8 @@ struct srp_target_port {
 	char			target_name[32];
 	unsigned int		scsi_id;
 	unsigned int		sg_tablesize;
+	int			queue_size;
+	int			req_ring_size;
 	int			comp_vector;
 	int			tl_retry_count;
 
@@ -173,9 +172,9 @@ struct srp_target_port {
 
 	int			zero_req_lim;
 
-	struct srp_iu	       *tx_ring[SRP_SQ_SIZE];
-	struct srp_iu	       *rx_ring[SRP_RQ_SIZE];
-	struct srp_request	req_ring[SRP_CMD_SQ_SIZE];
+	struct srp_iu	       **tx_ring;
+	struct srp_iu	       **rx_ring;
+	struct srp_request	*req_ring;
 
 	struct work_struct	tl_err_work;
 	struct work_struct	remove_work;
-- 
1.8.1.4

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Re: [PATCH 10/10] IB/srp: Make queue size configurable

[Jack Wang]

On 10/10/2013 02:19 PM, Bart Van Assche wrote:
> Certain storage configurations, e.g. a sufficiently large array of
> hard disks in a RAID configuration, need a queue depth above 64 to
> achieve optimal performance. Hence make the queue depth configurable.
> 
Hello Bart,

It's better to mention user may need to bump the configuration on target
side, as we adjust can_queue to req_lim when receive login response.

Patch looks good to me, if needed you can add my Tested-by.

Thanks,
Jack


> Signed-off-by: Bart Van Assche <bvanassche-HInyCGIudOg@public.gmane.org>
> Cc: David Dillow <dillowda-1Heg1YXhbW8@public.gmane.org>
> Cc: Roland Dreier <roland-BHEL68pLQRGGvPXPguhicg@public.gmane.org>
> Cc: Vu Pham <vu-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
> Cc: Sebastian Riemer <sebastian.riemer-EIkl63zCoXaH+58JC4qpiA@public.gmane.org>
> Cc: Konrad Grzybowski <konrad.grzybowski-XLFqaoR9dsI@public.gmane.org>
> ---
>  drivers/infiniband/ulp/srp/ib_srp.c | 125 +++++++++++++++++++++++++++---------
>  drivers/infiniband/ulp/srp/ib_srp.h |  17 +++--
>  2 files changed, 103 insertions(+), 39 deletions(-)
> 
> diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
> index fdc0bc1..b0a37ff 100644
> --- a/drivers/infiniband/ulp/srp/ib_srp.c
> +++ b/drivers/infiniband/ulp/srp/ib_srp.c
> @@ -299,16 +299,16 @@ static int srp_create_target_ib(struct srp_target_port *target)
>  		return -ENOMEM;
>  
>  	recv_cq = ib_create_cq(target->srp_host->srp_dev->dev,
> -			       srp_recv_completion, NULL, target, SRP_RQ_SIZE,
> -			       target->comp_vector);
> +			       srp_recv_completion, NULL, target,
> +			       target->queue_size, target->comp_vector);
>  	if (IS_ERR(recv_cq)) {
>  		ret = PTR_ERR(recv_cq);
>  		goto err;
>  	}
>  
>  	send_cq = ib_create_cq(target->srp_host->srp_dev->dev,
> -			       srp_send_completion, NULL, target, SRP_SQ_SIZE,
> -			       target->comp_vector);
> +			       srp_send_completion, NULL, target,
> +			       target->queue_size, target->comp_vector);
>  	if (IS_ERR(send_cq)) {
>  		ret = PTR_ERR(send_cq);
>  		goto err_recv_cq;
> @@ -317,8 +317,8 @@ static int srp_create_target_ib(struct srp_target_port *target)
>  	ib_req_notify_cq(recv_cq, IB_CQ_NEXT_COMP);
>  
>  	init_attr->event_handler       = srp_qp_event;
> -	init_attr->cap.max_send_wr     = SRP_SQ_SIZE;
> -	init_attr->cap.max_recv_wr     = SRP_RQ_SIZE;
> +	init_attr->cap.max_send_wr     = target->queue_size;
> +	init_attr->cap.max_recv_wr     = target->queue_size;
>  	init_attr->cap.max_recv_sge    = 1;
>  	init_attr->cap.max_send_sge    = 1;
>  	init_attr->sq_sig_type         = IB_SIGNAL_ALL_WR;
> @@ -364,6 +364,10 @@ err:
>  	return ret;
>  }
>  
> +/*
> + * Note: this function may be called without srp_alloc_iu_bufs() having been
> + * invoked. Hence the target->[rt]x_ring checks.
> + */
>  static void srp_free_target_ib(struct srp_target_port *target)
>  {
>  	int i;
> @@ -375,10 +379,18 @@ static void srp_free_target_ib(struct srp_target_port *target)
>  	target->qp = NULL;
>  	target->send_cq = target->recv_cq = NULL;
>  
> -	for (i = 0; i < SRP_RQ_SIZE; ++i)
> -		srp_free_iu(target->srp_host, target->rx_ring[i]);
> -	for (i = 0; i < SRP_SQ_SIZE; ++i)
> -		srp_free_iu(target->srp_host, target->tx_ring[i]);
> +	if (target->rx_ring) {
> +		for (i = 0; i < target->queue_size; ++i)
> +			srp_free_iu(target->srp_host, target->rx_ring[i]);
> +		kfree(target->rx_ring);
> +		target->rx_ring = NULL;
> +	}
> +	if (target->tx_ring) {
> +		for (i = 0; i < target->queue_size; ++i)
> +			srp_free_iu(target->srp_host, target->tx_ring[i]);
> +		kfree(target->tx_ring);
> +		target->tx_ring = NULL;
> +	}
>  }
>  
>  static void srp_path_rec_completion(int status,
> @@ -564,7 +576,11 @@ static void srp_free_req_data(struct srp_target_port *target)
>  	struct srp_request *req;
>  	int i;
>  
> -	for (i = 0, req = target->req_ring; i < SRP_CMD_SQ_SIZE; ++i, ++req) {
> +	if (!target->req_ring)
> +		return;
> +
> +	for (i = 0; i < target->req_ring_size; ++i) {
> +		req = &target->req_ring[i];
>  		kfree(req->fmr_list);
>  		kfree(req->map_page);
>  		if (req->indirect_dma_addr) {
> @@ -574,6 +590,9 @@ static void srp_free_req_data(struct srp_target_port *target)
>  		}
>  		kfree(req->indirect_desc);
>  	}
> +
> +	kfree(target->req_ring);
> +	target->req_ring = NULL;
>  }
>  
>  static int srp_alloc_req_data(struct srp_target_port *target)
> @@ -586,7 +605,12 @@ static int srp_alloc_req_data(struct srp_target_port *target)
>  
>  	INIT_LIST_HEAD(&target->free_reqs);
>  
> -	for (i = 0; i < SRP_CMD_SQ_SIZE; ++i) {
> +	target->req_ring = kzalloc(target->req_ring_size *
> +				   sizeof(*target->req_ring), GFP_KERNEL);
> +	if (!target->req_ring)
> +		goto out;
> +
> +	for (i = 0; i < target->req_ring_size; ++i) {
>  		req = &target->req_ring[i];
>  		req->fmr_list = kmalloc(target->cmd_sg_cnt * sizeof(void *),
>  					GFP_KERNEL);
> @@ -811,7 +835,7 @@ static void srp_terminate_io(struct srp_rport *rport)
>  	struct srp_target_port *target = rport->lld_data;
>  	int i;
>  
> -	for (i = 0; i < SRP_CMD_SQ_SIZE; ++i) {
> +	for (i = 0; i < target->req_ring_size; ++i) {
>  		struct srp_request *req = &target->req_ring[i];
>  		srp_finish_req(target, req, DID_TRANSPORT_FAILFAST << 16);
>  	}
> @@ -848,13 +872,13 @@ static int srp_rport_reconnect(struct srp_rport *rport)
>  	else
>  		srp_create_target_ib(target);
>  
> -	for (i = 0; i < SRP_CMD_SQ_SIZE; ++i) {
> +	for (i = 0; i < target->req_ring_size; ++i) {
>  		struct srp_request *req = &target->req_ring[i];
>  		srp_finish_req(target, req, DID_RESET << 16);
>  	}
>  
>  	INIT_LIST_HEAD(&target->free_tx);
> -	for (i = 0; i < SRP_SQ_SIZE; ++i)
> +	for (i = 0; i < target->queue_size; ++i)
>  		list_add(&target->tx_ring[i]->list, &target->free_tx);
>  
>  	if (ret == 0)
> @@ -1562,11 +1586,24 @@ err_unlock:
>  	return SCSI_MLQUEUE_HOST_BUSY;
>  }
>  
> +/*
> + * Note: the resources allocated in this function are freed in
> + * srp_free_target_ib().
> + */
>  static int srp_alloc_iu_bufs(struct srp_target_port *target)
>  {
>  	int i;
>  
> -	for (i = 0; i < SRP_RQ_SIZE; ++i) {
> +	target->rx_ring = kzalloc(target->queue_size * sizeof(*target->rx_ring),
> +				  GFP_KERNEL);
> +	if (!target->rx_ring)
> +		goto err_no_ring;
> +	target->tx_ring = kzalloc(target->queue_size * sizeof(*target->tx_ring),
> +				  GFP_KERNEL);
> +	if (!target->tx_ring)
> +		goto err_no_ring;
> +
> +	for (i = 0; i < target->queue_size; ++i) {
>  		target->rx_ring[i] = srp_alloc_iu(target->srp_host,
>  						  target->max_ti_iu_len,
>  						  GFP_KERNEL, DMA_FROM_DEVICE);
> @@ -1574,7 +1611,7 @@ static int srp_alloc_iu_bufs(struct srp_target_port *target)
>  			goto err;
>  	}
>  
> -	for (i = 0; i < SRP_SQ_SIZE; ++i) {
> +	for (i = 0; i < target->queue_size; ++i) {
>  		target->tx_ring[i] = srp_alloc_iu(target->srp_host,
>  						  target->max_iu_len,
>  						  GFP_KERNEL, DMA_TO_DEVICE);
> @@ -1587,16 +1624,18 @@ static int srp_alloc_iu_bufs(struct srp_target_port *target)
>  	return 0;
>  
>  err:
> -	for (i = 0; i < SRP_RQ_SIZE; ++i) {
> +	for (i = 0; i < target->queue_size; ++i) {
>  		srp_free_iu(target->srp_host, target->rx_ring[i]);
> -		target->rx_ring[i] = NULL;
> -	}
> -
> -	for (i = 0; i < SRP_SQ_SIZE; ++i) {
>  		srp_free_iu(target->srp_host, target->tx_ring[i]);
> -		target->tx_ring[i] = NULL;
>  	}
>  
> +
> +err_no_ring:
> +	kfree(target->tx_ring);
> +	target->tx_ring = NULL;
> +	kfree(target->rx_ring);
> +	target->rx_ring = NULL;
> +
>  	return -ENOMEM;
>  }
>  
> @@ -1647,6 +1686,9 @@ static void srp_cm_rep_handler(struct ib_cm_id *cm_id,
>  		target->scsi_host->can_queue
>  			= min(target->req_lim - SRP_TSK_MGMT_SQ_SIZE,
>  			      target->scsi_host->can_queue);
> +		target->scsi_host->cmd_per_lun
> +			= min_t(int, target->scsi_host->can_queue,
> +				target->scsi_host->cmd_per_lun);
>  	} else {
>  		shost_printk(KERN_WARNING, target->scsi_host,
>  			     PFX "Unhandled RSP opcode %#x\n", lrsp->opcode);
> @@ -1654,7 +1696,7 @@ static void srp_cm_rep_handler(struct ib_cm_id *cm_id,
>  		goto error;
>  	}
>  
> -	if (!target->rx_ring[0]) {
> +	if (!target->rx_ring) {
>  		ret = srp_alloc_iu_bufs(target);
>  		if (ret)
>  			goto error;
> @@ -1674,7 +1716,7 @@ static void srp_cm_rep_handler(struct ib_cm_id *cm_id,
>  	if (ret)
>  		goto error_free;
>  
> -	for (i = 0; i < SRP_RQ_SIZE; i++) {
> +	for (i = 0; i < target->queue_size; i++) {
>  		struct srp_iu *iu = target->rx_ring[i];
>  		ret = srp_post_recv(target, iu);
>  		if (ret)
> @@ -1933,7 +1975,7 @@ static int srp_reset_device(struct scsi_cmnd *scmnd)
>  	if (target->tsk_mgmt_status)
>  		return FAILED;
>  
> -	for (i = 0; i < SRP_CMD_SQ_SIZE; ++i) {
> +	for (i = 0; i < target->req_ring_size; ++i) {
>  		struct srp_request *req = &target->req_ring[i];
>  		if (req->scmnd && req->scmnd->device == scmnd->device)
>  			srp_finish_req(target, req, DID_RESET << 16);
> @@ -2136,9 +2178,9 @@ static struct scsi_host_template srp_template = {
>  	.eh_host_reset_handler		= srp_reset_host,
>  	.skip_settle_delay		= true,
>  	.sg_tablesize			= SRP_DEF_SG_TABLESIZE,
> -	.can_queue			= SRP_CMD_SQ_SIZE,
> +	.can_queue			= SRP_DEFAULT_CMD_SQ_SIZE,
>  	.this_id			= -1,
> -	.cmd_per_lun			= SRP_CMD_SQ_SIZE,
> +	.cmd_per_lun			= SRP_DEFAULT_CMD_SQ_SIZE,
>  	.use_clustering			= ENABLE_CLUSTERING,
>  	.shost_attrs			= srp_host_attrs
>  };
> @@ -2245,6 +2287,7 @@ enum {
>  	SRP_OPT_SG_TABLESIZE	= 1 << 11,
>  	SRP_OPT_COMP_VECTOR	= 1 << 12,
>  	SRP_OPT_TL_RETRY_COUNT	= 1 << 13,
> +	SRP_OPT_CAN_QUEUE	= 1 << 14,
>  	SRP_OPT_ALL		= (SRP_OPT_ID_EXT	|
>  				   SRP_OPT_IOC_GUID	|
>  				   SRP_OPT_DGID		|
> @@ -2267,6 +2310,7 @@ static const match_table_t srp_opt_tokens = {
>  	{ SRP_OPT_SG_TABLESIZE,		"sg_tablesize=%u"	},
>  	{ SRP_OPT_COMP_VECTOR,		"comp_vector=%u"	},
>  	{ SRP_OPT_TL_RETRY_COUNT,	"tl_retry_count=%u"	},
> +	{ SRP_OPT_CAN_QUEUE,		"can_queue=%d"		},
>  	{ SRP_OPT_ERR,			NULL 			}
>  };
>  
> @@ -2361,13 +2405,25 @@ static int srp_parse_options(const char *buf, struct srp_target_port *target)
>  			target->scsi_host->max_sectors = token;
>  			break;
>  
> +		case SRP_OPT_CAN_QUEUE:
> +			if (match_int(args, &token) || token < 1) {
> +				pr_warn("bad can_queue parameter '%s'\n", p);
> +				goto out;
> +			}
> +			target->scsi_host->can_queue = token;
> +			target->queue_size = token + SRP_RSP_SQ_SIZE +
> +					     SRP_TSK_MGMT_SQ_SIZE;
> +			if (!(opt_mask & SRP_OPT_MAX_CMD_PER_LUN))
> +				target->scsi_host->cmd_per_lun = token;
> +			break;
> +
>  		case SRP_OPT_MAX_CMD_PER_LUN:
> -			if (match_int(args, &token)) {
> +			if (match_int(args, &token) || token < 1) {
>  				pr_warn("bad max cmd_per_lun parameter '%s'\n",
>  					p);
>  				goto out;
>  			}
> -			target->scsi_host->cmd_per_lun = min(token, SRP_CMD_SQ_SIZE);
> +			target->scsi_host->cmd_per_lun = token;
>  			break;
>  
>  		case SRP_OPT_IO_CLASS:
> @@ -2455,6 +2511,12 @@ static int srp_parse_options(const char *buf, struct srp_target_port *target)
>  				pr_warn("target creation request is missing parameter '%s'\n",
>  					srp_opt_tokens[i].pattern);
>  
> +	if (target->scsi_host->cmd_per_lun > target->scsi_host->can_queue
> +	    && (opt_mask & SRP_OPT_MAX_CMD_PER_LUN))
> +		pr_warn("cmd_per_lun = %d > can_queue = %d\n",
> +			target->scsi_host->cmd_per_lun,
> +			target->scsi_host->can_queue);
> +
>  out:
>  	kfree(options);
>  	return ret;
> @@ -2493,11 +2555,14 @@ static ssize_t srp_create_target(struct device *dev,
>  	target->sg_tablesize	= indirect_sg_entries ? : cmd_sg_entries;
>  	target->allow_ext_sg	= allow_ext_sg;
>  	target->tl_retry_count	= 7;
> +	target->queue_size	= SRP_DEFAULT_QUEUE_SIZE;
>  
>  	ret = srp_parse_options(buf, target);
>  	if (ret)
>  		goto err;
>  
> +	target->req_ring_size = target->queue_size - SRP_TSK_MGMT_SQ_SIZE;
> +
>  	if (!srp_conn_unique(target->srp_host, target)) {
>  		shost_printk(KERN_INFO, target->scsi_host,
>  			     PFX "Already connected to target port with id_ext=%016llx;ioc_guid=%016llx;initiator_ext=%016llx\n",
> diff --git a/drivers/infiniband/ulp/srp/ib_srp.h b/drivers/infiniband/ulp/srp/ib_srp.h
> index 446b045..5756810 100644
> --- a/drivers/infiniband/ulp/srp/ib_srp.h
> +++ b/drivers/infiniband/ulp/srp/ib_srp.h
> @@ -57,14 +57,11 @@ enum {
>  	SRP_MAX_LUN		= 512,
>  	SRP_DEF_SG_TABLESIZE	= 12,
>  
> -	SRP_RQ_SHIFT    	= 6,
> -	SRP_RQ_SIZE		= 1 << SRP_RQ_SHIFT,
> -
> -	SRP_SQ_SIZE		= SRP_RQ_SIZE,
> +	SRP_DEFAULT_QUEUE_SIZE	= 1 << 6,
>  	SRP_RSP_SQ_SIZE		= 1,
> -	SRP_REQ_SQ_SIZE		= SRP_SQ_SIZE - SRP_RSP_SQ_SIZE,
>  	SRP_TSK_MGMT_SQ_SIZE	= 1,
> -	SRP_CMD_SQ_SIZE		= SRP_REQ_SQ_SIZE - SRP_TSK_MGMT_SQ_SIZE,
> +	SRP_DEFAULT_CMD_SQ_SIZE = SRP_DEFAULT_QUEUE_SIZE - SRP_RSP_SQ_SIZE -
> +				  SRP_TSK_MGMT_SQ_SIZE,
>  
>  	SRP_TAG_NO_REQ		= ~0U,
>  	SRP_TAG_TSK_MGMT	= 1U << 31,
> @@ -156,6 +153,8 @@ struct srp_target_port {
>  	char			target_name[32];
>  	unsigned int		scsi_id;
>  	unsigned int		sg_tablesize;
> +	int			queue_size;
> +	int			req_ring_size;
>  	int			comp_vector;
>  	int			tl_retry_count;
>  
> @@ -173,9 +172,9 @@ struct srp_target_port {
>  
>  	int			zero_req_lim;
>  
> -	struct srp_iu	       *tx_ring[SRP_SQ_SIZE];
> -	struct srp_iu	       *rx_ring[SRP_RQ_SIZE];
> -	struct srp_request	req_ring[SRP_CMD_SQ_SIZE];
> +	struct srp_iu	       **tx_ring;
> +	struct srp_iu	       **rx_ring;
> +	struct srp_request	*req_ring;
>  
>  	struct work_struct	tl_err_work;
>  	struct work_struct	remove_work;
> 

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Re: [PATCH 03/10] scsi_transport_srp: Add transport layer error handling

[Bart Van Assche]

[-- Attachment #1: Type: text/plain, Size: 901 bytes --]

On 10/10/13 14:12, Bart Van Assche wrote:
> Add the necessary functions in the SRP transport module to allow
> an SRP initiator driver to implement transport layer error handling
> similar to the functionality already provided by the FC transport
> layer. 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.
[ ... ]

(replying to my own e-mail)

Since it takes some work to figure out the state transitions from the 
source code, I have tried to draw a diagram representing all state 
transitions. I have attached that diagram to this e-mail. That diagram 
probably will make it easier to review this code.

Bart.




[-- Attachment #2: srp-initiator-states.svg --]
[-- Type: image/svg+xml, Size: 8311 bytes --]

Re: [PATCH 10/10] IB/srp: Make queue size configurable

[David Dillow]

On Thu, 2013-10-10 at 14:19 +0200, Bart Van Assche wrote:
> @@ -2267,6 +2310,7 @@ static const match_table_t srp_opt_tokens = {
>         { SRP_OPT_SG_TABLESIZE,         "sg_tablesize=%u"       },
>         { SRP_OPT_COMP_VECTOR,          "comp_vector=%u"        },
>         { SRP_OPT_TL_RETRY_COUNT,       "tl_retry_count=%u"     },
> +       { SRP_OPT_CAN_QUEUE,            "can_queue=%d"          },
>         { SRP_OPT_ERR,                  NULL                    }

Minor question -- I thought you had ended up suggesting queue_size
instead of can_queue here?
-- 
Dave Dillow
National Center for Computational Science
Oak Ridge National Laboratory
(865) 241-6602 office

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Re: [PATCH 0/10] IB SRP initiator patches for kernel 3.12

[David Dillow]

On Thu, 2013-10-10 at 14:05 +0200, Bart Van Assche wrote:
> The purpose of this InfiniBand SRP initiator patch series is as follows:
> - Make the SRP initiator driver better suited for use in a H.A. setup.
>    Add fast_io_fail_tmo, dev_loss_tmo and reconnect_delay parameters.
>    With the default values of these parameters failover happens
>    significantly faster. The dev_loss mechanism can be disabled which
>    makes it possible to avoid device removal which is necessary when
>    e.g. using initiator side mirroring.
> - Improve performance by making the queue size configurable.
> - Make it possible to figure out which SCSI host corresponds to which
>    SRP initiator port by making the SGID (source GID) available in sysfs.

Many of these already have it, but for patches 1-10:

Acked-by: David Dillow <dillowda-1Heg1YXhbW8@public.gmane.org>

-- 
Dave Dillow
National Center for Computational Science
Oak Ridge National Laboratory
(865) 241-6602 office

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Re: [PATCH 03/10] scsi_transport_srp: Add transport layer error handling

[David Dillow]

On Sat, 2013-10-19 at 18:13 +0200, Bart Van Assche wrote:
> Since it takes some work to figure out the state transitions from the 
> source code, I have tried to draw a diagram representing all state 
> transitions. I have attached that diagram to this e-mail. That diagram 
> probably will make it easier to review this code.

This is handy, Bart -- could you put it in a patch? I suppose it belongs
under Documentation/infiniband...

Thanks!

-- 
Dave Dillow
National Center for Computational Science
Oak Ridge National Laboratory
(865) 241-6602 office

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Re: [PATCH 10/10] IB/srp: Make queue size configurable

[Bart Van Assche]

On 10/26/13 00:13, David Dillow wrote:
> On Thu, 2013-10-10 at 14:19 +0200, Bart Van Assche wrote:
>> @@ -2267,6 +2310,7 @@ static const match_table_t srp_opt_tokens = {
>>          { SRP_OPT_SG_TABLESIZE,         "sg_tablesize=%u"       },
>>          { SRP_OPT_COMP_VECTOR,          "comp_vector=%u"        },
>>          { SRP_OPT_TL_RETRY_COUNT,       "tl_retry_count=%u"     },
>> +       { SRP_OPT_CAN_QUEUE,            "can_queue=%d"          },
>>          { SRP_OPT_ERR,                  NULL                    }
>
> Minor question -- I thought you had ended up suggesting queue_size
> instead of can_queue here?

Sorry, forgot to change that. Will post an update.

Bart.


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Re: [PATCH 03/10] scsi_transport_srp: Add transport layer error handling

[Bart Van Assche]

On 10/26/13 00:42, David Dillow wrote:
> On Sat, 2013-10-19 at 18:13 +0200, Bart Van Assche wrote:
>> Since it takes some work to figure out the state transitions from the
>> source code, I have tried to draw a diagram representing all state
>> transitions. I have attached that diagram to this e-mail. That diagram
>> probably will make it easier to review this code.
>
> This is handy, Bart -- could you put it in a patch? I suppose it belongs
> under Documentation/infiniband...

Hello Dave,

That sounds like a good idea to me. I will post such a patch as soon as 
possible - the coming two weeks I will be traveling.

Bart.