8155eb0785
This patch adds implicit updates to the sysfs entries that read the diagnostic data stored in the "caching buffer" for Exchange Port Data. An update is triggered once the buffer is older than ZFCP_DIAG_MAX_AGE milliseconds (5s). This entails sending an Exchange Port Data command to the FCP-Channel, and during its ingress path updating the cached data and the timestamp. To prevent multiple concurrent userspace-applications from triggering this update in parallel we synchronize all of them using a wait-queue (waiting threads are interruptible; the updating thread is not). Link: https://lore.kernel.org/r/c145b5cfc99a63b6a018b1184fbd27bb09c955f5.1572018132.git.bblock@linux.ibm.com Reviewed-by: Steffen Maier <maier@linux.ibm.com> Signed-off-by: Benjamin Block <bblock@linux.ibm.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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.