e263c5b2e8
It is quite common for a userpace program to fetch the buffered amount of data in the rx queue to avoid the read block. Implement the TIOCINQ ioctl to make the migration to the WWAN port usage smooth. Despite the fact that the read call will return no more data than the size of a first skb in the queue, TIOCINQ returns the entire amount of buffered data (sum of all queued skbs). This is done to prevent the breaking of programs that optimize reading, avoiding it if the buffered amount of data is too small. Signed-off-by: Sergey Ryazanov <ryazanov.s.a@gmail.com> Reviewed-by: Loic Poulain <loic.poulain@linaro.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.