[PATCH v2 3/6] drm/amdgpu: Use drm_timeout_abs_to_jiffies()

amdgpu_gem_timeout() converts an absolute deadline in ns into jiffies,
which is what drm_timeout_abs_to_jiffies() already does for the other
drivers whose wait UAPI takes a deadline. Use the shared helper and keep
only the part that is specific to amdgpu, which was improved with a
clearer comment.

Two details change along this conversion: the helper rounds up rather than
truncating, so a deadline less than a tick away now waits for one jiffy
instead of returning 0. It also uses nsecs_to_jiffies64(), so the
conversion no longer truncates on 32-bit, where a large deadline could
previously be reduced to an arbitrary shorter one.

Signed-off-by: Maíra Canal <[email protected]>

---

As a note, this patch can be merged independently to the AMD tree
without any dependencies.
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c | 20 ++++----------------
 1 file changed, 4 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
index 6a0699746fbc..beadd657c09a 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
@@ -25,7 +25,6 @@
  *          Alex Deucher
  *          Jerome Glisse
  */
-#include <linux/ktime.h>
 #include <linux/module.h>
 #include <linux/overflow.h>
 #include <linux/pagemap.h>
@@ -40,6 +39,7 @@
 #include <drm/drm_gem_ttm_helper.h>
 #include <drm/ttm/ttm_tt.h>
 #include <drm/drm_syncobj.h>
+#include <drm/drm_utils.h>
 
 #include "amdgpu.h"
 #include "amdgpu_display.h"
@@ -622,23 +622,11 @@ int amdgpu_gem_mmap_ioctl(struct drm_device *dev, void *data,
  */
 unsigned long amdgpu_gem_timeout(uint64_t timeout_ns)
 {
-	unsigned long timeout_jiffies;
-	ktime_t timeout;
-
-	/* clamp timeout if it's to large */
-	if (((int64_t)timeout_ns) < 0)
+	/* Map anything that doesn't fit in a s64 to an infinite wait */
+	if (timeout_ns > S64_MAX)
 		return MAX_SCHEDULE_TIMEOUT;
 
-	timeout = ktime_sub(ns_to_ktime(timeout_ns), ktime_get());
-	if (ktime_to_ns(timeout) < 0)
-		return 0;
-
-	timeout_jiffies = nsecs_to_jiffies(ktime_to_ns(timeout));
-	/*  clamp timeout to avoid unsigned-> signed overflow */
-	if (timeout_jiffies > MAX_SCHEDULE_TIMEOUT)
-		return MAX_SCHEDULE_TIMEOUT - 1;
-
-	return timeout_jiffies;
+	return drm_timeout_abs_to_jiffies(timeout_ns);
 }
 
 int amdgpu_gem_wait_idle_ioctl(struct drm_device *dev, void *data,

-- 
2.55.0