[Intel-gfx] [PATCH 07/15] drm/i915: Check the timeout passed to i915_wait_request

[Chris Wilson]

We have relied upon the sole caller (wait_ioctl) validating the timeout
argument. However, when waiting for multiple requests I forgot to ensure
that the timeout was still positive on the later requests. This is more
simply done inside __i915_wait_request.

Fixes a minor regression introduced in

commit b47161858ba13c9c7e03333132230d66e008dd55
Author: Chris Wilson <chris at chris-wilson.co.uk>
Date:   Mon Apr 27 13:41:17 2015 +0100

    drm/i915: Implement inter-engine read-read optimisations

where we may end up waiting for an extra jiffie for each active ring
after consuming all of the user's timeout.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Lionel Landwerlin <lionel.g.landwerlin at linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
---
 drivers/gpu/drm/i915/i915_gem.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index f33c35c6130f..65d101b47d8e 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1251,8 +1251,16 @@ int __i915_wait_request(struct drm_i915_gem_request *req,
 	if (i915_gem_request_completed(req, true))
 		return 0;
 
-	timeout_expire = timeout ?
-		jiffies + nsecs_to_jiffies_timeout((u64)*timeout) : 0;
+	timeout_expire = 0;
+	if (timeout) {
+		if (WARN_ON(*timeout < 0))
+			return -EINVAL;
+
+		if (*timeout == 0)
+			return -ETIME;
+
+		timeout_expire = jiffies + nsecs_to_jiffies_timeout(*timeout);
+	}
 
 	if (INTEL_INFO(dev_priv)->gen >= 6)
 		gen6_rps_boost(dev_priv, rps, req->emitted_jiffies);
-- 
2.6.2