From 49b9f86a594a5403641e6e60508788a7310fd293 Mon Sep 17 00:00:00 2001 From: Nilay Shroff Date: Wed, 21 May 2025 18:11:23 +0530 Subject: [PATCH] nvme: avoid creating multipath sysfs group under namespace path devices Commit 4dbd2b2ebe4c ("nvme-multipath: Add visibility for round-robin io-policy") introduced the creation of the multipath sysfs group under the NVMe head gendisk device node. However, it also inadvertently added the same sysfs group under each namespace path device which head node refers to and that is incorrect. The multipath sysfs group should only be exposed through the namespace head gendisk node. This is sufficient, as the head device already provides symbolic links to the individual namespace paths it manages. This patch fixes the issue by preventing the creation of the multipath sysfs group under namespace path devices, ensuring it only appears under the head disk node. Fixes: 4dbd2b2ebe4c ("nvme-multipath: Add visibility for round-robin io-policy") Signed-off-by: Nilay Shroff Signed-off-by: Christoph Hellwig --- drivers/nvme/host/sysfs.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) diff --git a/drivers/nvme/host/sysfs.c b/drivers/nvme/host/sysfs.c index 6d31226f7a4f..a5bc3bb483d5 100644 --- a/drivers/nvme/host/sysfs.c +++ b/drivers/nvme/host/sysfs.c @@ -306,13 +306,41 @@ static const struct attribute_group nvme_ns_attr_group = { }; #ifdef CONFIG_NVME_MULTIPATH +/* + * NOTE: The dummy attribute does not appear in sysfs. It exists solely to allow + * control over the visibility of the multipath sysfs node. Without at least one + * attribute defined in nvme_ns_mpath_attrs[], the sysfs implementation does not + * invoke the multipath_sysfs_group_visible() method. As a result, we would not + * be able to control the visibility of the multipath sysfs node. + */ +static struct attribute dummy_attr = { + .name = "dummy", +}; + static struct attribute *nvme_ns_mpath_attrs[] = { + &dummy_attr, NULL, }; +static bool multipath_sysfs_group_visible(struct kobject *kobj) +{ + struct device *dev = container_of(kobj, struct device, kobj); + + return nvme_disk_is_ns_head(dev_to_disk(dev)); +} + +static bool multipath_sysfs_attr_visible(struct kobject *kobj, + struct attribute *attr, int n) +{ + return false; +} + +DEFINE_SYSFS_GROUP_VISIBLE(multipath_sysfs) + const struct attribute_group nvme_ns_mpath_attr_group = { .name = "multipath", .attrs = nvme_ns_mpath_attrs, + .is_visible = SYSFS_GROUP_VISIBLE(multipath_sysfs), }; #endif -- 2.49.0