tree 146ad73ff1ee9439263678c5493a5c2d180ad794
parent 74aee796c613f54e9f089170df548c0b3f15af69
author David VomLehn <dvomlehn@cisco.com> 1251489267 -0700
committer Greg Kroah-Hartman <gregkh@suse.de> 1253713594 -0700

USB: use kfifo to buffer usb-generic serial writes

When do_output_char() attempts to write a carriage return/line feed sequence,
it first checks to see how much buffer room is available. If there are at least
two characters free, it will write the carriage return/line feed with two calls
to tty_put_char(). It calls the tty_operation functions write() for devices that
don't support the tty_operations function put_char(). If the USB generic serial
device's write URB is not in use, it will return the buffer size when asked how
much room is available. The write() of the carriage return will cause it to mark
the write URB busy, so the subsequent write() of the line feed will be ignored.

This patch uses the kfifo infrastructure to implement a write FIFO that
accurately returns the amount of space available in the buffer.

Signed-off-by: David VomLehn <dvomlehn@cisco.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>