IB/hfi1: Add sysfs interface for affinity setup

Some users want more control over which cpu cores are being used by the
driver. For example, users might want to restrict the driver to some
specified subset of the cores so that they can appropriately partition
processes, irq handlers, and work threads.
To allow the user to fine tune system affinity settings new sysfs
attributes are introduced per sdma engine.  This patch adds a new
attribute type for sdma engine and a new cpu_list attribute.
When the user writes a cpu range to the cpu_list attribute the driver
will create an internal cpu->sdma map, which will be used later as a
look-up table to choose an optimal engine for a user requests.

Reviewed-by: Dean Luick <dean.luick@intel.com>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Reviewed-by: Sebastian Sanchez <sebastian.sanchez@intel.com>
Reviewed-by: Jianxin Xiong <jianxin.xiong@intel.com>
Signed-off-by: Tadeusz Struk <tadeusz.struk@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

1 files changed, 89 insertions, 1 deletions

diff --git a/drivers/infiniband/hw/hfi1/sysfs.c b/drivers/infiniband/hw/hfi1/sysfs.c
index 74c84c655f7e..836eea58e4ff 100644
--- a/drivers/infiniband/hw/hfi1/sysfs.c
+++ b/drivers/infiniband/hw/hfi1/sysfs.c
@@ -766,13 +766,82 @@ bail:
 	return ret;
 }
 
+struct sde_attribute {
+	struct attribute attr;
+	ssize_t (*show)(struct sdma_engine *sde, char *buf);
+	ssize_t (*store)(struct sdma_engine *sde, const char *buf, size_t cnt);
+};
+
+static ssize_t sde_show(struct kobject *kobj, struct attribute *attr, char *buf)
+{
+	struct sde_attribute *sde_attr =
+		container_of(attr, struct sde_attribute, attr);
+	struct sdma_engine *sde =
+		container_of(kobj, struct sdma_engine, kobj);
+
+	if (!sde_attr->show)
+		return -EINVAL;
+
+	return sde_attr->show(sde, buf);
+}
+
+static ssize_t sde_store(struct kobject *kobj, struct attribute *attr,
+			 const char *buf, size_t count)
+{
+	struct sde_attribute *sde_attr =
+		container_of(attr, struct sde_attribute, attr);
+	struct sdma_engine *sde =
+		container_of(kobj, struct sdma_engine, kobj);
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	if (!sde_attr->store)
+		return -EINVAL;
+
+	return sde_attr->store(sde, buf, count);
+}
+
+static const struct sysfs_ops sde_sysfs_ops = {
+	.show = sde_show,
+	.store = sde_store,
+};
+
+static struct kobj_type sde_ktype = {
+	.sysfs_ops = &sde_sysfs_ops,
+};
+
+#define SDE_ATTR(_name, _mode, _show, _store) \
+	struct sde_attribute sde_attr_##_name = \
+		__ATTR(_name, _mode, _show, _store)
+
+static ssize_t sde_show_cpu_to_sde_map(struct sdma_engine *sde, char *buf)
+{
+	return sdma_get_cpu_to_sde_map(sde, buf);
+}
+
+static ssize_t sde_store_cpu_to_sde_map(struct sdma_engine *sde,
+					const char *buf, size_t count)
+{
+	return sdma_set_cpu_to_sde_map(sde, buf, count);
+}
+
+static SDE_ATTR(cpu_list, S_IWUSR | S_IRUGO,
+		sde_show_cpu_to_sde_map,
+		sde_store_cpu_to_sde_map);
+
+static struct sde_attribute *sde_attribs[] = {
+	&sde_attr_cpu_list
+};
+
 /*
  * Register and create our files in /sys/class/infiniband.
  */
 int hfi1_verbs_register_sysfs(struct hfi1_devdata *dd)
 {
 	struct ib_device *dev = &dd->verbs_dev.rdi.ibdev;
-	int i, ret;
+	struct device *class_dev = &dev->dev;
+	int i, j, ret;
 
 	for (i = 0; i < ARRAY_SIZE(hfi1_attributes); ++i) {
 		ret = device_create_file(&dev->dev, hfi1_attributes[i]);
@@ -780,10 +849,29 @@ int hfi1_verbs_register_sysfs(struct hfi1_devdata *dd)
 			goto bail;
 	}
 
+	for (i = 0; i < dd->num_sdma; i++) {
+		ret = kobject_init_and_add(&dd->per_sdma[i].kobj,
+					   &sde_ktype, &class_dev->kobj,
+					   "sdma%d", i);
+		if (ret)
+			goto bail;
+
+		for (j = 0; j < ARRAY_SIZE(sde_attribs); j++) {
+			ret = sysfs_create_file(&dd->per_sdma[i].kobj,
+						&sde_attribs[j]->attr);
+			if (ret)
+				goto bail;
+		}
+	}
+
 	return 0;
 bail:
 	for (i = 0; i < ARRAY_SIZE(hfi1_attributes); ++i)
 		device_remove_file(&dev->dev, hfi1_attributes[i]);
+
+	for (i = 0; i < dd->num_sdma; i++)
+		kobject_del(&dd->per_sdma[i].kobj);
+
 	return ret;
 }