On Sun, Feb 12, 2012 at 01:40:47PM +0100, Jiri Slaby wrote: > > Is tty_kref_put() safe in interrupt? Here it seems to be OK, but in other > > callers... More or less at random: drivers/tty/serial/lantiq.c has it > > called from lqasc_rx_int(). It seems to be possible to have it end up > > calling ->ops->shutdown() and in this case that'd be lqasc_shutdown(). > > Which does a bunch of free_irq(), including the ->rx_irq, i.e. the one > > we have it called from. Alan? > > I'm not Alan, but will reply anyway. Yes, it is safe (unless the driver > does something tricky). In the driver you mention, this is uart_ops, > called from tty_port_operations' ->shutdown. And that's a different from > tty_operations' ->shutdown. > > Yes, there are: > * tty->ops > * tty_port->ops > * uart_port->ops > > uart_port->ops->shutdown is supposed to tear down interrupts like in > lantiq.c. It is called from tty_port->ops->shutdown. And that one is > allowed to be called only from user context (tty->ops->close and > tty->ops->hangup).
Yecchhh... If I'm reading (and grepping) it right, there are only two non-default instance of tty_operations ->shutdown() - pty and vt ones. Lovely... And while we are at it, vt instance is definitely not safe from interrupts - calls console_lock(). Not that it was relevant in this case... It's probably too late in this case, but I would've called that method ->sync_cleanup(). Assuming I'm not misreading its intent and history... ------------------------------------------------------------------------------ Virtualization & Cloud Management Using Capacity Planning Cloud computing makes use of virtualization - but cloud computing also focuses on allowing computing to be delivered as a service. http://www.accelacomm.com/jaw/sfnl/114/51521223/ _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel
