sysfs: Add sysfs_update_groups function

Adding sysfs_update_groups function to update
multiple groups.

  sysfs_update_groups - given a directory kobject, create a bunch of attribute groups
  @kobj:      The kobject to update the group on
  @groups:    The attribute groups to update, NULL terminated

This function update a bunch of attribute groups.  If an error occurs when
updating a group, all previously updated groups will be removed together
with already existing (not updated) attributes.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190512155518.21468-2-jolsa@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/fs/sysfs/group.c b/fs/sysfs/group.c
index 5703860..d41c21f 100644 (file)
--- a/fs/sysfs/group.c
+++ b/fs/sysfs/group.c
@@ -175,6 +175,26 @@ int sysfs_create_group(struct kobject *kobj,
 }
 EXPORT_SYMBOL_GPL(sysfs_create_group);
 
+static int internal_create_groups(struct kobject *kobj, int update,
+                                 const struct attribute_group **groups)
+{
+       int error = 0;
+       int i;
+
+       if (!groups)
+               return 0;
+
+       for (i = 0; groups[i]; i++) {
+               error = internal_create_group(kobj, update, groups[i]);
+               if (error) {
+                       while (--i >= 0)
+                               sysfs_remove_group(kobj, groups[i]);
+                       break;
+               }
+       }
+       return error;
+}
+
 /**
  * sysfs_create_groups - given a directory kobject, create a bunch of attribute groups
  * @kobj:      The kobject to create the group on
@@ -191,25 +211,29 @@ EXPORT_SYMBOL_GPL(sysfs_create_group);
 int sysfs_create_groups(struct kobject *kobj,
                        const struct attribute_group **groups)
 {
-       int error = 0;
-       int i;
-
-       if (!groups)
-               return 0;
-
-       for (i = 0; groups[i]; i++) {
-               error = sysfs_create_group(kobj, groups[i]);
-               if (error) {
-                       while (--i >= 0)
-                               sysfs_remove_group(kobj, groups[i]);
-                       break;
-               }
-       }
-       return error;
+       return internal_create_groups(kobj, 0, groups);
 }
 EXPORT_SYMBOL_GPL(sysfs_create_groups);
 
 /**
+ * sysfs_update_groups - given a directory kobject, create a bunch of attribute groups
+ * @kobj:      The kobject to update the group on
+ * @groups:    The attribute groups to update, NULL terminated
+ *
+ * This function update a bunch of attribute groups.  If an error occurs when
+ * updating a group, all previously updated groups will be removed together
+ * with already existing (not updated) attributes.
+ *
+ * Returns 0 on success or error code from sysfs_update_group on failure.
+ */
+int sysfs_update_groups(struct kobject *kobj,
+                       const struct attribute_group **groups)
+{
+       return internal_create_groups(kobj, 1, groups);
+}
+EXPORT_SYMBOL_GPL(sysfs_update_groups);
+
+/**
  * sysfs_update_group - given a directory kobject, update an attribute group
  * @kobj:      The kobject to update the group on
  * @grp:       The attribute group to update

diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
index 786816c..9652367 100644 (file)
--- a/include/linux/sysfs.h
+++ b/include/linux/sysfs.h
@@ -268,6 +268,8 @@ int __must_check sysfs_create_group(struct kobject *kobj,
                                    const struct attribute_group *grp);
 int __must_check sysfs_create_groups(struct kobject *kobj,
                                     const struct attribute_group **groups);
+int __must_check sysfs_update_groups(struct kobject *kobj,
+                                    const struct attribute_group **groups);
 int sysfs_update_group(struct kobject *kobj,
                       const struct attribute_group *grp);
 void sysfs_remove_group(struct kobject *kobj,
@@ -433,6 +435,12 @@ static inline int sysfs_create_groups(struct kobject *kobj,
        return 0;
 }
 
+static inline int sysfs_update_groups(struct kobject *kobj,
+                                     const struct attribute_group **groups)
+{
+       return 0;
+}
+
 static inline int sysfs_update_group(struct kobject *kobj,
                                const struct attribute_group *grp)
 {