[PATCH v2 02/10] sysfs: introduce callback attribute_group::bin_size
From: Thomas Weißschuh <linux@weissschuh.net>
Date: 2024-11-03 17:04:38
Also in:
amd-gfx, dri-devel, linux-alpha, linux-cxl, linux-pci, linux-rdma, linux-scsi, linux-usb, linuxppc-dev, lkml, platform-driver-x86
Subsystem:
driver core, kobjects, debugfs and sysfs, filesystems (vfs and infrastructure), the rest · Maintainers:
Greg Kroah-Hartman, "Rafael J. Wysocki", Danilo Krummrich, Alexander Viro, Christian Brauner, Linus Torvalds
Several drivers need to dynamically calculate the size of an binary attribute. Currently this is done by assigning attr->size from the is_bin_visible() callback. This has drawbacks: * It is not documented. * A single attribute can be instantiated multiple times, overwriting the shared size field. * It prevents the structure to be moved to read-only memory. Introduce a new dedicated callback to calculate the size of the attribute. Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> --- fs/sysfs/group.c | 2 ++ include/linux/sysfs.h | 8 ++++++++ 2 files changed, 10 insertions(+)
diff --git a/fs/sysfs/group.c b/fs/sysfs/group.c
index 45b2e92941da1f49dcc71af3781317c61480c956..8b01a7eda5fb3239e138372417d01967c7a3f122 100644
--- a/fs/sysfs/group.c
+++ b/fs/sysfs/group.c@@ -98,6 +98,8 @@ static int create_files(struct kernfs_node *parent, struct kobject *kobj, if (!mode) continue; } + if (grp->bin_size) + size = grp->bin_size(kobj, *bin_attr, i); WARN(mode & ~(SYSFS_PREALLOC | 0664), "Attribute %s: Invalid permissions 0%o\n",
diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
index c4e64dc112063f7cb89bf66059d0338716089e87..4746cccb95898b24df6f53de9421ea7649b5568f 100644
--- a/include/linux/sysfs.h
+++ b/include/linux/sysfs.h@@ -87,6 +87,11 @@ do { \ * SYSFS_GROUP_VISIBLE() when assigning this callback to * specify separate _group_visible() and _attr_visible() * handlers. + * @bin_size: + * Optional: Function to return the size of a binary attribute + * of the group. Will be called repeatedly for each binary + * attribute in the group. Overwrites the size field embedded + * inside the attribute itself. * @attrs: Pointer to NULL terminated list of attributes. * @bin_attrs: Pointer to NULL terminated list of binary attributes. * Either attrs or bin_attrs or both must be provided.
@@ -97,6 +102,9 @@ struct attribute_group { struct attribute *, int); umode_t (*is_bin_visible)(struct kobject *, struct bin_attribute *, int); + size_t (*bin_size)(struct kobject *, + const struct bin_attribute *, + int); struct attribute **attrs; struct bin_attribute **bin_attrs; };
--
2.47.0