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authorAlan Stern <stern@rowland.harvard.edu>2007-03-15 15:50:34 -0400
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-03-15 15:29:26 -0700
commitd9a9cdfb078d755e648d53ec25b7370f84ee5729 (patch)
tree308380483fd6241b1d0ef5916b9329c1c5df00f6 /fs/sysfs
parent6ab27c6bf38d5ff71dafeca77b79e7c284804b75 (diff)
[PATCH] sysfs and driver core: add callback helper, used by SCSI and S390
This patch (as868) adds a helper routine for device drivers that need to set up a callback to perform some action in a different process's context. This is intended for use by attribute methods that want to unregister themselves or their parent device. Attribute method calls are mutually exclusive with unregistration, so such actions cannot be taken directly. Two attribute methods are converted to use the new helper routine: one for SCSI device deletion and one for System/390 ccwgroup devices. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Cc: Hugh Dickins <hugh@veritas.com> Cc: Cornelia Huck <cornelia.huck@de.ibm.com> Cc: Oliver Neukum <oneukum@suse.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/sysfs')
-rw-r--r--fs/sysfs/file.c54
1 files changed, 54 insertions, 0 deletions
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index 8d4d839a9d8..1bafdf6e171 100644
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -629,6 +629,60 @@ void sysfs_remove_file_from_group(struct kobject *kobj,
}
EXPORT_SYMBOL_GPL(sysfs_remove_file_from_group);
+struct sysfs_schedule_callback_struct {
+ struct kobject *kobj;
+ void (*func)(void *);
+ void *data;
+ struct work_struct work;
+};
+
+static void sysfs_schedule_callback_work(struct work_struct *work)
+{
+ struct sysfs_schedule_callback_struct *ss = container_of(work,
+ struct sysfs_schedule_callback_struct, work);
+
+ (ss->func)(ss->data);
+ kobject_put(ss->kobj);
+ kfree(ss);
+}
+
+/**
+ * sysfs_schedule_callback - helper to schedule a callback for a kobject
+ * @kobj: object we're acting for.
+ * @func: callback function to invoke later.
+ * @data: argument to pass to @func.
+ *
+ * sysfs attribute methods must not unregister themselves or their parent
+ * kobject (which would amount to the same thing). Attempts to do so will
+ * deadlock, since unregistration is mutually exclusive with driver
+ * callbacks.
+ *
+ * Instead methods can call this routine, which will attempt to allocate
+ * and schedule a workqueue request to call back @func with @data as its
+ * argument in the workqueue's process context. @kobj will be pinned
+ * until @func returns.
+ *
+ * Returns 0 if the request was submitted, -ENOMEM if storage could not
+ * be allocated.
+ */
+int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *),
+ void *data)
+{
+ struct sysfs_schedule_callback_struct *ss;
+
+ ss = kmalloc(sizeof(*ss), GFP_KERNEL);
+ if (!ss)
+ return -ENOMEM;
+ kobject_get(kobj);
+ ss->kobj = kobj;
+ ss->func = func;
+ ss->data = data;
+ INIT_WORK(&ss->work, sysfs_schedule_callback_work);
+ schedule_work(&ss->work);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(sysfs_schedule_callback);
+
EXPORT_SYMBOL_GPL(sysfs_create_file);
EXPORT_SYMBOL_GPL(sysfs_remove_file);