From 4a84eacedc55e78c8f64a5a4f9ade6e285844b85 Mon Sep 17 00:00:00 2001 From: Ioana Ciornei Date: Mon, 25 Jun 2018 13:19:53 +0300 Subject: [PATCH] drivers/base: add sysfs entries for suppliers and consumers Instead of scraping dmesg for messages such as 'Linked as a consumer to' or 'Dropping the link to' export two new sysfs entries in the device folder that list the consumer and supplier devices. Signed-off-by: Ioana Ciornei --- Documentation/ABI/testing/sysfs-devices-links | 13 +++++++++ drivers/base/core.c | 42 +++++++++++++++++++++++++++ 2 files changed, 55 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-devices-links --- /dev/null +++ b/Documentation/ABI/testing/sysfs-devices-links @@ -0,0 +1,13 @@ +What: /sys/devices/.../consumers +Date: October 2018 +Contact: Ioana Ciornei +Description: + Read-only attribute that lists the current "consumers" of + a specific device. + +What: /sys/devices/.../suppliers +Date: October 2018 +Contact: Ioana Ciornei +Description: + Read-only attribute that lists the current "suppliers" of + a specific device. --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -1333,6 +1333,34 @@ static ssize_t online_store(struct devic } static DEVICE_ATTR_RW(online); +static ssize_t suppliers_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct device_link *link; + size_t count = 0; + + list_for_each_entry(link, &dev->links.suppliers, c_node) + count += scnprintf(buf + count, PAGE_SIZE - count, "%s\n", + dev_name(link->supplier)); + + return count; +} +static DEVICE_ATTR_RO(suppliers); + +static ssize_t consumers_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct device_link *link; + size_t count = 0; + + list_for_each_entry(link, &dev->links.consumers, s_node) + count += scnprintf(buf + count, PAGE_SIZE - count, "%s\n", + dev_name(link->consumer)); + + return count; +} +static DEVICE_ATTR_RO(consumers); + int device_add_groups(struct device *dev, const struct attribute_group **groups) { return sysfs_create_groups(&dev->kobj, groups); @@ -1504,8 +1532,20 @@ static int device_add_attrs(struct devic goto err_remove_dev_groups; } + error = device_create_file(dev, &dev_attr_suppliers); + if (error) + goto err_remove_online; + + error = device_create_file(dev, &dev_attr_consumers); + if (error) + goto err_remove_suppliers; + return 0; + err_remove_suppliers: + device_remove_file(dev, &dev_attr_suppliers); + err_remove_online: + device_remove_file(dev, &dev_attr_online); err_remove_dev_groups: device_remove_groups(dev, dev->groups); err_remove_type_groups: @@ -1523,6 +1563,8 @@ static void device_remove_attrs(struct d struct class *class = dev->class; const struct device_type *type = dev->type; + device_remove_file(dev, &dev_attr_consumers); + device_remove_file(dev, &dev_attr_suppliers); device_remove_file(dev, &dev_attr_online); device_remove_groups(dev, dev->groups);