sfc: Convert to use hwmon_device_register_with_groups

Simplify the code. Avoid race conditions caused by attributes
being created after hwmon device registration. Implicitly
(through hwmon API) add mandatory 'name' sysfs attribute.

Reviewed-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 32 insertions, 48 deletions

diff --git a/drivers/net/ethernet/sfc/mcdi.h b/drivers/net/ethernet/sfc/mcdi.h
index 656a3277c2b2..15816cacb548 100644
--- a/drivers/net/ethernet/sfc/mcdi.h
+++ b/drivers/net/ethernet/sfc/mcdi.h
@@ -75,6 +75,8 @@ struct efx_mcdi_mon {
         unsigned long last_update;
         struct device *device;
         struct efx_mcdi_mon_attribute *attrs;
+        struct attribute_group group;
+        const struct attribute_group *groups[2];
         unsigned int n_attrs;
 };
 
diff --git a/drivers/net/ethernet/sfc/mcdi_mon.c b/drivers/net/ethernet/sfc/mcdi_mon.c
index 4cc5d95b2a5a..d72ad4fc3617 100644
--- a/drivers/net/ethernet/sfc/mcdi_mon.c
+++ b/drivers/net/ethernet/sfc/mcdi_mon.c
@@ -139,17 +139,10 @@ static int efx_mcdi_mon_update(struct efx_nic *efx)
         return rc;
 }
 
-static ssize_t efx_mcdi_mon_show_name(struct device *dev,
-                                      struct device_attribute *attr,
-                                      char *buf)
-{
-        return sprintf(buf, "%s\n", KBUILD_MODNAME);
-}
-
 static int efx_mcdi_mon_get_entry(struct device *dev, unsigned int index,
                                   efx_dword_t *entry)
 {
-        struct efx_nic *efx = dev_get_drvdata(dev);
+        struct efx_nic *efx = dev_get_drvdata(dev->parent);
         struct efx_mcdi_mon *hwmon = efx_mcdi_mon(efx);
         int rc;
 
@@ -263,7 +256,7 @@ static ssize_t efx_mcdi_mon_show_label(struct device *dev,
                        efx_mcdi_sensor_type[mon_attr->type].label);
 }
 
-static int
+static void
 efx_mcdi_mon_add_attr(struct efx_nic *efx, const char *name,
                       ssize_t (*reader)(struct device *,
                                         struct device_attribute *, char *),
@@ -272,7 +265,6 @@ efx_mcdi_mon_add_attr(struct efx_nic *efx, const char *name,
 {
         struct efx_mcdi_mon *hwmon = efx_mcdi_mon(efx);
         struct efx_mcdi_mon_attribute *attr = &hwmon->attrs[hwmon->n_attrs];
-        int rc;
 
         strlcpy(attr->name, name, sizeof(attr->name));
         attr->index = index;
@@ -286,10 +278,7 @@ efx_mcdi_mon_add_attr(struct efx_nic *efx, const char *name,
         attr->dev_attr.attr.name = attr->name;
         attr->dev_attr.attr.mode = S_IRUGO;
         attr->dev_attr.show = reader;
-        rc = device_create_file(&efx->pci_dev->dev, &attr->dev_attr);
-        if (rc == 0)
-                ++hwmon->n_attrs;
-        return rc;
+        hwmon->group.attrs[hwmon->n_attrs++] = &attr->dev_attr.attr;
 }
 
 int efx_mcdi_mon_probe(struct efx_nic *efx)
@@ -338,26 +327,22 @@ int efx_mcdi_mon_probe(struct efx_nic *efx)
         efx_mcdi_mon_update(efx);
 
         /* Allocate space for the maximum possible number of
-         * attributes for this set of sensors: name of the driver plus
+         * attributes for this set of sensors:
          * value, min, max, crit, alarm and label for each sensor.
          */
-        n_attrs = 1 + 6 * n_sensors;
+        n_attrs = 6 * n_sensors;
         hwmon->attrs = kcalloc(n_attrs, sizeof(*hwmon->attrs), GFP_KERNEL);
         if (!hwmon->attrs) {
                 rc = -ENOMEM;
                 goto fail;
         }
-
-        hwmon->device = hwmon_device_register(&efx->pci_dev->dev);
-        if (IS_ERR(hwmon->device)) {
-                rc = PTR_ERR(hwmon->device);
+        hwmon->group.attrs = kcalloc(n_attrs + 1, sizeof(struct attribute *),
+                                     GFP_KERNEL);
+        if (!hwmon->group.attrs) {
+                rc = -ENOMEM;
                 goto fail;
         }
 
-        rc = efx_mcdi_mon_add_attr(efx, "name", efx_mcdi_mon_show_name, 0, 0, 0);
-        if (rc)
-                goto fail;
-
         for (i = 0, j = -1, type = -1; ; i++) {
                 enum efx_hwmon_type hwmon_type;
                 const char *hwmon_prefix;
@@ -372,7 +357,7 @@ int efx_mcdi_mon_probe(struct efx_nic *efx)
                                 page = type / 32;
                                 j = -1;
                                 if (page == n_pages)
-                                        return 0;
+                                        goto hwmon_register;
 
                                 MCDI_SET_DWORD(inbuf, SENSOR_INFO_EXT_IN_PAGE,
                                                page);
@@ -453,28 +438,22 @@ int efx_mcdi_mon_probe(struct efx_nic *efx)
                 if (min1 != max1) {
                         snprintf(name, sizeof(name), "%s%u_input",
                                  hwmon_prefix, hwmon_index);
-                        rc = efx_mcdi_mon_add_attr(
+                        efx_mcdi_mon_add_attr(
                                 efx, name, efx_mcdi_mon_show_value, i, type, 0);
-                        if (rc)
-                                goto fail;
 
                         if (hwmon_type != EFX_HWMON_POWER) {
                                 snprintf(name, sizeof(name), "%s%u_min",
                                          hwmon_prefix, hwmon_index);
-                                rc = efx_mcdi_mon_add_attr(
+                                efx_mcdi_mon_add_attr(
                                         efx, name, efx_mcdi_mon_show_limit,
                                         i, type, min1);
-                                if (rc)
-                                        goto fail;
                         }
 
                         snprintf(name, sizeof(name), "%s%u_max",
                                  hwmon_prefix, hwmon_index);
-                        rc = efx_mcdi_mon_add_attr(
+                        efx_mcdi_mon_add_attr(
                                 efx, name, efx_mcdi_mon_show_limit,
                                 i, type, max1);
-                        if (rc)
-                                goto fail;
 
                         if (min2 != max2) {
                                 /* Assume max2 is critical value.
@@ -482,32 +461,38 @@ int efx_mcdi_mon_probe(struct efx_nic *efx)
                                  */
                                 snprintf(name, sizeof(name), "%s%u_crit",
                                          hwmon_prefix, hwmon_index);
-                                rc = efx_mcdi_mon_add_attr(
+                                efx_mcdi_mon_add_attr(
                                         efx, name, efx_mcdi_mon_show_limit,
                                         i, type, max2);
-                                if (rc)
-                                        goto fail;
                         }
                 }
 
                 snprintf(name, sizeof(name), "%s%u_alarm",
                          hwmon_prefix, hwmon_index);
-                rc = efx_mcdi_mon_add_attr(
+                efx_mcdi_mon_add_attr(
                         efx, name, efx_mcdi_mon_show_alarm, i, type, 0);
-                if (rc)
-                        goto fail;
 
                 if (type < ARRAY_SIZE(efx_mcdi_sensor_type) &&
                     efx_mcdi_sensor_type[type].label) {
                         snprintf(name, sizeof(name), "%s%u_label",
                                  hwmon_prefix, hwmon_index);
-                        rc = efx_mcdi_mon_add_attr(
+                        efx_mcdi_mon_add_attr(
                                 efx, name, efx_mcdi_mon_show_label, i, type, 0);
-                        if (rc)
-                                goto fail;
                 }
         }
 
+hwmon_register:
+        hwmon->groups[0] = &hwmon->group;
+        hwmon->device = hwmon_device_register_with_groups(&efx->pci_dev->dev,
+                                                          KBUILD_MODNAME, NULL,
+                                                          hwmon->groups);
+        if (IS_ERR(hwmon->device)) {
+                rc = PTR_ERR(hwmon->device);
+                goto fail;
+        }
+
+        return 0;
+
 fail:
         efx_mcdi_mon_remove(efx);
         return rc;
@@ -516,14 +501,11 @@ fail:
 void efx_mcdi_mon_remove(struct efx_nic *efx)
 {
         struct efx_mcdi_mon *hwmon = efx_mcdi_mon(efx);
-        unsigned int i;
 
-        for (i = 0; i < hwmon->n_attrs; i++)
-                device_remove_file(&efx->pci_dev->dev,
-                                   &hwmon->attrs[i].dev_attr);
-        kfree(hwmon->attrs);
         if (hwmon->device)
                 hwmon_device_unregister(hwmon->device);
+        kfree(hwmon->attrs);
+        kfree(hwmon->group.attrs);
         efx_nic_free_buffer(efx, &hwmon->dma_buf);
 }