[Intel-gfx] [PATCH 1/2] drm/i915: compute wait_ioctl timeout correctly

[Daniel Vetter]

We've lost the +1 required for correct timeouts in

commit 5ed0bdf21a85d78e04f89f15ccf227562177cbd9
Author: Thomas Gleixner <tglx at linutronix.de>
Date:   Wed Jul 16 21:05:06 2014 +0000

    drm: i915: Use nsec based interfaces

    Use ktime_get_raw_ns() and get rid of the back and forth timespec
    conversions.

    Signed-off-by: Thomas Gleixner <tglx at linutronix.de>
    Acked-by: Daniel Vetter <daniel.vetter at ffwll.ch>
    Signed-off-by: John Stultz <john.stultz at linaro.org>

So fix this up by reinstating our handrolled _timeout function. While
at it bother with handling MAX_JIFFIES.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=82749
Cc: Thomas Gleixner <tglx at linutronix.de>
Cc: John Stultz <john.stultz at linaro.org>
Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
---
 drivers/gpu/drm/i915/i915_drv.h | 10 ++++++++++
 drivers/gpu/drm/i915/i915_gem.c |  3 ++-
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 02b3cb32c8a6..caae337c0199 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -3030,6 +3030,16 @@ static inline unsigned long msecs_to_jiffies_timeout(const unsigned int m)
 	return min_t(unsigned long, MAX_JIFFY_OFFSET, j + 1);
 }
 
+static inline unsigned long nsecs_to_jiffies_timeout(const u64 m)
+{
+	unsigned long j = nsecs_to_jiffies(m);
+
+	if (m > (u64)jiffies_to_usecs(MAX_JIFFY_OFFSET) * 1000)
+		return MAX_JIFFY_OFFSET;
+
+	return min_t(unsigned long, MAX_JIFFY_OFFSET, j + 1);
+}
+
 static inline unsigned long
 timespec_to_jiffies_timeout(const struct timespec *value)
 {
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 23e17735a6a9..002730d1409b 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1225,7 +1225,8 @@ int __i915_wait_seqno(struct intel_engine_cs *ring, u32 seqno,
 	if (i915_seqno_passed(ring->get_seqno(ring, true), seqno))
 		return 0;
 
-	timeout_expire = timeout ? jiffies + nsecs_to_jiffies((u64)*timeout) : 0;
+	timeout_expire = timeout ?
+		jiffies + nsecs_to_jiffies_timeout((u64)*timeout) : 0;
 
 	if (INTEL_INFO(dev)->gen >= 6 && ring->id == RCS && can_wait_boost(file_priv)) {
 		gen6_rps_boost(dev_priv);
-- 
1.9.3