On Thu, 9 Jan 2014, David Laight wrote: > > From: Sarah Sharp > > Currently prepare_ring() returns -ENOMEM if the urb won't fit into a > > single ring segment. usb_sg_wait() treats this error as a temporary > > condition and will keep retrying until something else goes wrong. > > Even if it were a temporary condition then an immediate retry > is rather pointless. > Retry after a slight delay might make some sense.
There is a yield(). It could be changed to something longer. > Of course, if this is the pagedaemon trying to write out > pages in order to generate some free kernel memory all is lost > as soon as the usb subsystem need to allocate memory in order > to perform a transfer. That never happens, because all memory allocation requests on the storage I/O pathway are done using GFP_NOIO. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
