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The wait-ioctl is optionally supplied a timeout with nanosecond precision in a s64 field. We use nsecs_to_jiffies64() to convert that into the jiffies consumed by the scheduler, but internally nsecs_to_jiffies64() does not guard against overflow (as it's purpose is for use by the scheduler and not drivers!). So we must guard against the overflow ourselves, and in the process note that we may then return much earlier than the timeout selected by the user, so don't report ETIME unless we do hit the timeout. (Woe betold us though if the user waits for a year (32bit) and the request is still not complete!) v2: Refine overflow detection (to not include an overffow itself) Reported-by: Jason Ekstrand <jason.ekstrand@intel.com> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Link: https://patchwork.freedesktop.org/patch/msgid/20170811105731.9482-1-chris@chris-wilson.co.uk Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.