Driver core: fix race in sysfs between sysfs_remove_file() and read()/write()
This patch prevents a race between IO and removing a file from sysfs.
It introduces a list of sysfs_buffers associated with a file at the inode.
Upon removal of a file the list is walked and the buffers marked orphaned.
IO to orphaned buffers fails with -ENODEV. The driver can safely free
associated data structures or be unloaded.
Signed-off-by: Oliver Neukum <oliver@neukum.name>
Acked-by: Maneesh Soni <maneesh@in.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h
index bd7cec2..39c623f 100644
--- a/fs/sysfs/sysfs.h
+++ b/fs/sysfs/sysfs.h
@@ -33,6 +33,22 @@
struct kobject * target_kobj;
};
+struct sysfs_buffer {
+ struct list_head associates;
+ size_t count;
+ loff_t pos;
+ char * page;
+ struct sysfs_ops * ops;
+ struct semaphore sem;
+ int orphaned;
+ int needs_read_fill;
+ int event;
+};
+
+struct sysfs_buffer_collection {
+ struct list_head associates;
+};
+
static inline struct kobject * to_kobj(struct dentry * dentry)
{
struct sysfs_dirent * sd = dentry->d_fsdata;