From ff1750101351a225754ca4a14b83275c766cf540 Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Wed, 21 Aug 2019 05:20:44 +0100
Subject: drm/i915/gtt: Relax assertion for pt_used
Git-commit: ff1750101351a225754ca4a14b83275c766cf540
Patch-mainline: v5.4-rc1
References: bsc#1152489
When inserting the final level PTE, we check that we are not overflowing
the page table (checking that pt_used does not exceed the size of the
table). However, we have to allow for every other PTE to be pinned by a
simultaneous removal thread (as on remove we bump the pt_used counter
before adjusting the table).
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190821042044.7354-1-chris@chris-wilson.co.uk
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
---
drivers/gpu/drm/i915/i915_gem_gtt.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 2cd2dabbcd3b..c9a4690bf8b1 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -1110,7 +1110,8 @@ static int __gen8_ppgtt_alloc(struct i915_address_space * const vm,
atomic_read(&pt->used));
atomic_add(count, &pt->used);
- GEM_BUG_ON(atomic_read(&pt->used) > I915_PDES);
+ /* All other pdes may be simultaneously removed */
+ GEM_BUG_ON(atomic_read(&pt->used) > 2 * I915_PDES);
*start += count;
}
} while (idx++, --len);
--
2.28.0