Hello, Eric. Eric W. Biederman wrote: > Looking carefully at the rename code we have a subtle dependency > that the structure of sysfs not change while we are performing > a rename. If the parent directory of the object we are renaming > changes while the rename is being performed nasty things could > happen when we go to release our locks. > > So introduce a sysfs_rename_mutex to prevent this highly > unlikely theoretical issue. Yeah, it's a theoretical issue. Rename/move implementation has always depended on the parent structure not changing beneath it, but it's nice to tighten up loose ends. > +DEFINE_MUTEX(sysfs_rename_mutex); Probably doesn't really matter but wouldn't a rwsem fit better? > @@ -774,7 +775,7 @@ static struct dentry *__sysfs_get_dentry(struct super_block *sb, struct sysfs_di > * down from there looking up dentry for each step. > * > * LOCKING: > - * Kernel thread context (may sleep) > + * mutex_lock(sysfs_rename_mutex) LOCKING describes what locks should be held when entering the function, so proper description would be something like... Kernel thread context, grabs sysfs_rename_mutex Thanks. -- tejun - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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