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5df7731f60
As Geert Uytterhoeven reported: for parameter HZ/50 in congestion_wait(BLK_RW_ASYNC, HZ/50); On some platforms, HZ can be less than 50, then unexpected 0 timeout jiffies will be set in congestion_wait(). This patch introduces a macro DEFAULT_IO_TIMEOUT to wrap a determinate value with msecs_to_jiffies(20) to instead HZ/50 to avoid such issue. Quoted from Geert Uytterhoeven: "A timeout of HZ means 1 second. HZ/50 means 20 ms, but has the risk of being zero, if HZ < 50. If you want to use a timeout of 20 ms, you best use msecs_to_jiffies(20), as that takes care of the special cases, and never returns 0." Signed-off-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
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.