On 08/14/2012 06:03 PM, Cyrill Gorcunov wrote: > This patch brings ability to plug in auxiliary fdinfo providers. > For example in further patches eventfd, evenpoll and fsnotify > will print out information associated with files. > > This feature is CONFIG_CHECKPOINT_RESTORE guarded to eliminate > overhead for those who don't need it at all (this > unfortunately makes patch bigger than I wanted). > > The basic usage rule is the following > > - fdinfo provider should register own "show" method > via proc_register_fdinfo_driver call, where "show" > methods are rather well known seq-file operations > > - once the kernel opens /proc/$pid/fdinfo/$fd file > it calls for ->probe() method in registered fdinfo > drivers, and if probe success, then seq-file "show" > operations will be called to provide out additional > infomation > > Initially we considered to inject some "show" metod to > file_operations but since there really a number of > file_operations declared inside kernel (and in real the > further patches cover onle eventfd/epoll/inotify) the > waste of memory space will be inacceptable I think. > > Pavel, I've left seq_next memthod as it was simply because > we can't leave seq_next() after calling extra->driver->ops->start > without increasing "pos", thus we need to call for "show" manually > once. > > Signed-off-by: Cyrill Gorcunov <gorcunov@xxxxxxxxxx> > CC: Al Viro <viro@xxxxxxxxxxxxxxxxxx> > CC: Alexey Dobriyan <adobriyan@xxxxxxxxx> > CC: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > CC: Pavel Emelyanov <xemul@xxxxxxxxxxxxx> > CC: James Bottomley <jbottomley@xxxxxxxxxxxxx> Acked-by: Pavel Emelyanov <xemul@xxxxxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
