052ada0968
For non SOCK_USE_WRITE_QUEUE sockets, sock_wfree() (atomically) puts ->sk_wmem_alloc twice. It's needed to keep the socket alive while calling ->sk_write_space() after the first put. However, some sockets, such as UDP, are freed by RCU (i.e. SOCK_RCU_FREE) and use already RCU-safe sock_def_write_space(). Carve a fast path for such sockets, put down all refs in one go before calling sock_def_write_space() but guard the socket from being freed by an RCU read section. note: because TCP sockets are marked with SOCK_USE_WRITE_QUEUE it doesn't add extra checks in its path. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> 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.