[Intel-gfx] [PATCH v2] drm/i915: Handle full s64 precision for wait-ioctl

[Chris Wilson]

Quoting Joonas Lahtinen (2017-08-14 11:42:05)
> On Fri, 2017-08-11 at 11:57 +0100, Chris Wilson wrote:
> > 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 at intel.com>
> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> > Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
> > Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> 
> Reviewed-by: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>

And pushed, thanks for the review.
-Chris