[PATCH V3 0/2] Function for improved node descriptions

[PATCH V3 0/2] Function for improved node descriptions

[Michael Heinz]

Changes from Version 2:

Changed the function to skip over '%' fields that aren't supported and added
code to ensure the string is null terminated no matter how it was formatted.

Changed the default description to more closely match the current OFED behavior.
The new default is '%h HCA-%d'. For example:

homer HCA-mthca0
node-a2 HCA-qib1
lisa HCA-mlx4_0

Changes from Version 1:

Replaced the original substitution of the hostname for '@' with an 
implementation of the '%h' and '%d' fields.

Description:

The common practice in IB fabrics is to set the description of an HCA to be
the hostname of the machine plus a description (i.e., "myhost hca-1",
"myhost hca-2", etc..)

This has a limitation, however.  The first is that if the machine's hostname
is set via DHCP, the HCA description may be set before the hostname is, leading
to an incorrect description. This can also occur if the machine's hostname
changes for some other reason after boot.

This can cause difficulties and confusion when trying to maintain a large
fabric - if all your nodes are described as "localhost HCA-1" it can be very
difficult to figure out which node is suffering from symbol errors.

This patch addresses the problem by providing a function to build the node
description. If the provided source string for the description contains a '%h'
it will be replaced at read time with the hostname of the node. If the provided
source string contains a '%d' it will be replaced at read time with the name of
the HCA.  For example, if the node description of the second HCA on node-a13 is
set to'%h: %d', at read time this will be expanded to read "node-a2: qib1".

This ensures that even after a fabric has been completely initialized, if a
node's hostname changes, that change will be reflected in the next "heavy"
sweep of the SM, but also maintains compatibility with existing code since the
behavior is unchanged if the description string does not contain a '%'
character.

---

Michael Heinz (2):
      Function for improved node descriptions
      Add support for ib_build_node_desc() to the HCAs.


 drivers/infiniband/core/mad.c                |   39 ++++++++++++++++++++++++++
 drivers/infiniband/hw/ipath/ipath_mad.c      |    2 +
 drivers/infiniband/hw/ipath/ipath_verbs.c    |    3 +-
 drivers/infiniband/hw/mlx4/mad.c             |    2 +
 drivers/infiniband/hw/mlx4/main.c            |    2 +
 drivers/infiniband/hw/mthca/mthca_mad.c      |    2 +
 drivers/infiniband/hw/mthca/mthca_provider.c |    2 +
 drivers/infiniband/hw/qib/qib_mad.c          |    2 +
 drivers/infiniband/hw/qib/qib_verbs.c        |    3 +-
 include/rdma/ib_mad.h                        |    9 ++++++
 include/rdma/ib_verbs.h                      |    3 +-
 11 files changed, 58 insertions(+), 11 deletions(-)

-- 
Signed-off-by: Michael Heinz <michael.heinz-h88ZbnxC6KDQT0dZR+AlfA@public.gmane.org>
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[PATCH V3 1/2] Function for improved node descriptions

[Michael Heinz]

Changes from Version 2:

Changed the function to skip over '%' fields that aren't supported and added
code to ensure the string is null terminated no matter how it was formatted.

Changes from Version 1:

Replaced the original substitution of the hostname for '@' with an
implementation of the '%h' and '%d' fields.

Description:

This patch adds a function to do variable substitution in the node
description. If the node description contains a '%h' it will be replaced at
read time with the hostname of the node. If the provided source string
contains a '%d' it will be replaced at read time with the name of the HCA.

For example, if the node description of the second HCA on node-a13 is
set to'%h: %d', at read time this will be expanded to read "node-a2: qib1".

Signed-off-by: Michael Heinz <michael.heinz-h88ZbnxC6KDQT0dZR+AlfA@public.gmane.org>

---
 drivers/infiniband/core/mad.c |   39 +++++++++++++++++++++++++++++++++++++++
 include/rdma/ib_mad.h         |    9 +++++++++
 include/rdma/ib_verbs.h       |    3 ++-
 3 files changed, 50 insertions(+), 1 deletions(-)

diff --git a/drivers/infiniband/core/mad.c b/drivers/infiniband/core/mad.c
index 822cfdc..3b5751d 100644
--- a/drivers/infiniband/core/mad.c
+++ b/drivers/infiniband/core/mad.c
@@ -41,6 +41,7 @@
 #include "mad_rmpp.h"
 #include "smi.h"
 #include "agent.h"
+#include "linux/utsname.h"
 
 MODULE_LICENSE("Dual BSD/GPL");
 MODULE_DESCRIPTION("kernel IB MAD API");
@@ -932,6 +933,44 @@ int ib_get_mad_data_offset(u8 mgmt_class)
 }
 EXPORT_SYMBOL(ib_get_mad_data_offset);
 
+void ib_build_node_desc(struct ib_smp *smp, struct ib_device *dev)
+{
+	char *dest = smp->data;
+	char *end = dest + IB_DEVICE_DESC_MAX-1;
+	char *src = dev->node_desc;
+	char *field;
+
+	while (*src && (dest < end)) {
+		if (*src != '%') {
+			*dest++ = *src++;
+		} else {
+			src++;
+			switch (*src) {
+			case 'h':
+				field = init_utsname()->nodename;
+				src++;
+				for (; *field && (*field != '.') &&
+					(dest < end);)
+					*dest++ = *field++;
+				break;
+			case 'd':
+				field = dev->name;
+				src++;
+				for (; *field && (dest < end);)
+					*dest++ = *field++;
+				break;
+			default:
+				src++;
+			}
+		}
+	}
+	if (dest < end)
+		*dest = 0;
+	else
+		*end = 0;
+}
+EXPORT_SYMBOL(ib_build_node_desc);
+
 int ib_is_mad_class_rmpp(u8 mgmt_class)
 {
 	if ((mgmt_class == IB_MGMT_CLASS_SUBN_ADM) ||
diff --git a/include/rdma/ib_mad.h b/include/rdma/ib_mad.h
index d3b9401..417a371 100644
--- a/include/rdma/ib_mad.h
+++ b/include/rdma/ib_mad.h
@@ -40,6 +40,7 @@
 #include <linux/list.h>
 
 #include <rdma/ib_verbs.h>
+#include <rdma/ib_smi.h>
 
 /* Management base version */
 #define IB_MGMT_BASE_VERSION			1
@@ -637,6 +638,14 @@ int ib_is_mad_class_rmpp(u8 mgmt_class);
 int ib_get_mad_data_offset(u8 mgmt_class);
 
 /**
+ * ib_build_node_desc - copies the node description and replaces
+ * any @ markers with the present system node name.
+ * @dest: destination
+ * @src: source
+ */
+void ib_build_node_desc(struct ib_smp *smp, struct ib_device *dev);
+
+/**
  * ib_get_rmpp_segment - returns the data buffer for a given RMPP segment.
  * @send_buf: Previously allocated send data buffer.
  * @seg_num: number of segment to return
diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
index 55cd0a0..a5986af 100644
--- a/include/rdma/ib_verbs.h
+++ b/include/rdma/ib_verbs.h
@@ -938,6 +938,7 @@ enum ib_mad_result {
 };
 
 #define IB_DEVICE_NAME_MAX 64
+#define IB_DEVICE_DESC_MAX 64
 
 struct ib_cache {
 	rwlock_t                lock;
@@ -1165,7 +1166,7 @@ struct ib_device {
 	int			     uverbs_abi_ver;
 	u64			     uverbs_cmd_mask;
 
-	char			     node_desc[64];
+	char			     node_desc[IB_DEVICE_DESC_MAX];
 	__be64			     node_guid;
 	u32			     local_dma_lkey;
 	u8                           node_type;

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[PATCH V3 2/2] Add support for ib_build_node_desc() to the HCAs.

[Michael Heinz]

Changes from Version 2:

Changed the default description to more closely match the current OFED
behavior. The new default is '%h HCA-%d'. For example:

homer HCA-mthca0
node-a2 HCA-qib1
lisa HCA-mlx4_0

Changes from Version 1:

Changed the default node description for Mellanox and QLogic HCAs to read
"%h: %d <description>" where '<description>' is the old default value.

Description:

Adds support for ib_build_node_desc() to the QLogic and Mellanox HCA
drivers.

Signed-off-by: Michael Heinz <michael.heinz-h88ZbnxC6KDQT0dZR+AlfA@public.gmane.org>

---
 drivers/infiniband/hw/ipath/ipath_mad.c      |    2 +-
 drivers/infiniband/hw/ipath/ipath_verbs.c    |    3 +--
 drivers/infiniband/hw/mlx4/mad.c             |    2 +-
 drivers/infiniband/hw/mlx4/main.c            |    2 +-
 drivers/infiniband/hw/mthca/mthca_mad.c      |    2 +-
 drivers/infiniband/hw/mthca/mthca_provider.c |    2 +-
 drivers/infiniband/hw/qib/qib_mad.c          |    2 +-
 drivers/infiniband/hw/qib/qib_verbs.c        |    3 +--
 8 files changed, 8 insertions(+), 10 deletions(-)

diff --git a/drivers/infiniband/hw/ipath/ipath_mad.c b/drivers/infiniband/hw/ipath/ipath_mad.c
index ceb98ee..387eba7 100644
--- a/drivers/infiniband/hw/ipath/ipath_mad.c
+++ b/drivers/infiniband/hw/ipath/ipath_mad.c
@@ -60,7 +60,7 @@ static int recv_subn_get_nodedescription(struct ib_smp *smp,
 	if (smp->attr_mod)
 		smp->status |= IB_SMP_INVALID_FIELD;
 
-	memcpy(smp->data, ibdev->node_desc, sizeof(smp->data));
+	ib_build_node_desc(smp, ibdev);
 
 	return reply(smp);
 }
diff --git a/drivers/infiniband/hw/ipath/ipath_verbs.c b/drivers/infiniband/hw/ipath/ipath_verbs.c
index dd7f26d..11e66dc 100644
--- a/drivers/infiniband/hw/ipath/ipath_verbs.c
+++ b/drivers/infiniband/hw/ipath/ipath_verbs.c
@@ -2179,8 +2179,7 @@ int ipath_register_ib_device(struct ipath_devdata *dd)
 	dev->mmap = ipath_mmap;
 	dev->dma_ops = &ipath_dma_mapping_ops;
 
-	snprintf(dev->node_desc, sizeof(dev->node_desc),
-		 IPATH_IDSTR " %s", init_utsname()->nodename);
+	strncpy(dev->node_desc, "%h HCA-%d", IB_DEVICE_DESC_MAX);
 
 	ret = ib_register_device(dev, NULL);
 	if (ret)
diff --git a/drivers/infiniband/hw/mlx4/mad.c b/drivers/infiniband/hw/mlx4/mad.c
index 57ffa50..8c7205f 100644
--- a/drivers/infiniband/hw/mlx4/mad.c
+++ b/drivers/infiniband/hw/mlx4/mad.c
@@ -196,7 +196,7 @@ static void node_desc_override(struct ib_device *dev,
 	    mad->mad_hdr.method == IB_MGMT_METHOD_GET_RESP &&
 	    mad->mad_hdr.attr_id == IB_SMP_ATTR_NODE_DESC) {
 		spin_lock(&to_mdev(dev)->sm_lock);
-		memcpy(((struct ib_smp *) mad)->data, dev->node_desc, 64);
+		ib_build_node_desc((struct ib_smp *) mad, dev);
 		spin_unlock(&to_mdev(dev)->sm_lock);
 	}
 }
diff --git a/drivers/infiniband/hw/mlx4/main.c b/drivers/infiniband/hw/mlx4/main.c
index c7a6213..6e8109b 100644
--- a/drivers/infiniband/hw/mlx4/main.c
+++ b/drivers/infiniband/hw/mlx4/main.c
@@ -713,7 +713,7 @@ static int init_node_data(struct mlx4_ib_dev *dev)
 	if (err)
 		goto out;
 
-	memcpy(dev->ib_dev.node_desc, out_mad->data, 64);
+	strncpy(dev->ib_dev.node_desc, "%h HCA-%d", IB_DEVICE_DESC_MAX);
 
 	in_mad->attr_id = IB_SMP_ATTR_NODE_INFO;
 
diff --git a/drivers/infiniband/hw/mthca/mthca_mad.c b/drivers/infiniband/hw/mthca/mthca_mad.c
index 03a5953..57e11d5 100644
--- a/drivers/infiniband/hw/mthca/mthca_mad.c
+++ b/drivers/infiniband/hw/mthca/mthca_mad.c
@@ -153,7 +153,7 @@ static void node_desc_override(struct ib_device *dev,
 	    mad->mad_hdr.method == IB_MGMT_METHOD_GET_RESP &&
 	    mad->mad_hdr.attr_id == IB_SMP_ATTR_NODE_DESC) {
 		mutex_lock(&to_mdev(dev)->cap_mask_mutex);
-		memcpy(((struct ib_smp *) mad)->data, dev->node_desc, 64);
+		ib_build_node_desc((struct ib_smp *) mad, dev);
 		mutex_unlock(&to_mdev(dev)->cap_mask_mutex);
 	}
 }
diff --git a/drivers/infiniband/hw/mthca/mthca_provider.c b/drivers/infiniband/hw/mthca/mthca_provider.c
index 1e0b4b6..745bba3 100644
--- a/drivers/infiniband/hw/mthca/mthca_provider.c
+++ b/drivers/infiniband/hw/mthca/mthca_provider.c
@@ -1273,7 +1273,7 @@ static int mthca_init_node_data(struct mthca_dev *dev)
 		goto out;
 	}
 
-	memcpy(dev->ib_dev.node_desc, out_mad->data, 64);
+	strncpy(dev->ib_dev.node_desc, "%h HCA-%d", IB_DEVICE_DESC_MAX);
 
 	in_mad->attr_id = IB_SMP_ATTR_NODE_INFO;
 
diff --git a/drivers/infiniband/hw/qib/qib_mad.c b/drivers/infiniband/hw/qib/qib_mad.c
index 5ad224e..5139e3c 100644
--- a/drivers/infiniband/hw/qib/qib_mad.c
+++ b/drivers/infiniband/hw/qib/qib_mad.c
@@ -260,7 +260,7 @@ static int subn_get_nodedescription(struct ib_smp *smp,
 	if (smp->attr_mod)
 		smp->status |= IB_SMP_INVALID_FIELD;
 
-	memcpy(smp->data, ibdev->node_desc, sizeof(smp->data));
+	ib_build_node_desc(smp, ibdev);
 
 	return reply(smp);
 }
diff --git a/drivers/infiniband/hw/qib/qib_verbs.c b/drivers/infiniband/hw/qib/qib_verbs.c
index 9fab404..333505d 100644
--- a/drivers/infiniband/hw/qib/qib_verbs.c
+++ b/drivers/infiniband/hw/qib/qib_verbs.c
@@ -2157,8 +2157,7 @@ int qib_register_ib_device(struct qib_devdata *dd)
 	ibdev->mmap = qib_mmap;
 	ibdev->dma_ops = &qib_dma_mapping_ops;
 
-	snprintf(ibdev->node_desc, sizeof(ibdev->node_desc),
-		 QIB_IDSTR " %s", init_utsname()->nodename);
+	strncpy(ibdev->node_desc, "%h HCA-%d", IB_DEVICE_DESC_MAX);
 
 	ret = ib_register_device(ibdev, qib_create_port_files);
 	if (ret)

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