a16684742f
queue->state is a ternary spinlock in disguise, used by OSA's TX completion path to lock the Output Queue and flush any pending packets on it to the device. If the Queue is already locked by our TX code, setting the lock word to QETH_OUT_Q_LOCKED_FLUSH lets the TX completion code move on - the TX path will later take care of things when it unlocks the Queue. This sort of DIY locking is a non-starter of course, just let the TX completion path block on the spinlock when necessary. If that ends up causing additional latency due to lock contention, then converting the OSA path to use xmit_more is the right way to go forward. Also slightly expand the locked section and capture all of qeth_do_send_packet(), so that the update for the 'bufs_pack' statistics is done race-free. While reworking the TX completion path's code, remove a barrier() that doesn't make any sense. Signed-off-by: Julian Wiedmann <jwi@linux.ibm.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.