[PATCH 5.13 460/800] drm/i915/selftests: Reorder tasklet_disable vs local_bh_disable

From: Greg Kroah-Hartman
Date: Mon Jul 12 2021 - 04:40:23 EST


From: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>

[ Upstream commit 2328e1b35ac2bb003236c3268aabe456ffab8b56 ]

Due to a change in requirements that disallows tasklet_disable() being
called from atomic context, rearrange the selftest to avoid doing so.

<3> [324.942939] BUG: sleeping function called from invalid context at kernel/softirq.c:888
<3> [324.942952] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 5601, name: i915_selftest
<4> [324.942960] 1 lock held by i915_selftest/5601:
<4> [324.942963] #0: ffff888101d19240 (&dev->mutex){....}-{3:3}, at: device_driver_attach+0x18/0x50
<3> [324.942987] Preemption disabled at:
<3> [324.942990] [<ffffffffa026fbd2>] live_hold_reset.part.65+0xc2/0x2f0 [i915]
<4> [324.943255] CPU: 0 PID: 5601 Comm: i915_selftest Tainted: G U 5.13.0-rc5-CI-CI_DRM_10197+ #1
<4> [324.943259] Hardware name: Intel Corp. Geminilake/GLK RVP2 LP4SD (07), BIOS GELKRVPA.X64.0062.B30.1708222146 08/22/2017
<4> [324.943263] Call Trace:
<4> [324.943267] dump_stack+0x7f/0xad
<4> [324.943276] ___might_sleep.cold.123+0xf2/0x106
<4> [324.943286] tasklet_unlock_wait+0x2e/0xb0
<4> [324.943291] ? ktime_get_raw+0x81/0x120
<4> [324.943305] live_hold_reset.part.65+0x1ab/0x2f0 [i915]
<4> [324.943500] __i915_subtests.cold.7+0x42/0x92 [i915]
<4> [324.943723] ? __i915_live_teardown+0x50/0x50 [i915]
<4> [324.943922] ? __intel_gt_live_setup+0x30/0x30 [i915]

Fixes: da044747401fc ("tasklets: Replace spin wait in tasklet_unlock_wait()")
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx>
Signed-off-by: Matthew Auld <matthew.auld@xxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20210611060838.647973-1-thomas.hellstrom@xxxxxxxxxxxxxxx
(cherry picked from commit 35c6367f516090a3086d37e7023b08608d555aba)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/gpu/drm/i915/gt/selftest_execlists.c | 55 ++++++++++++--------
1 file changed, 32 insertions(+), 23 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/selftest_execlists.c b/drivers/gpu/drm/i915/gt/selftest_execlists.c
index 1081cd36a2bd..1e5d59a776b8 100644
--- a/drivers/gpu/drm/i915/gt/selftest_execlists.c
+++ b/drivers/gpu/drm/i915/gt/selftest_execlists.c
@@ -551,6 +551,32 @@ static int live_pin_rewind(void *arg)
return err;
}

+static int engine_lock_reset_tasklet(struct intel_engine_cs *engine)
+{
+ tasklet_disable(&engine->execlists.tasklet);
+ local_bh_disable();
+
+ if (test_and_set_bit(I915_RESET_ENGINE + engine->id,
+ &engine->gt->reset.flags)) {
+ local_bh_enable();
+ tasklet_enable(&engine->execlists.tasklet);
+
+ intel_gt_set_wedged(engine->gt);
+ return -EBUSY;
+ }
+
+ return 0;
+}
+
+static void engine_unlock_reset_tasklet(struct intel_engine_cs *engine)
+{
+ clear_and_wake_up_bit(I915_RESET_ENGINE + engine->id,
+ &engine->gt->reset.flags);
+
+ local_bh_enable();
+ tasklet_enable(&engine->execlists.tasklet);
+}
+
static int live_hold_reset(void *arg)
{
struct intel_gt *gt = arg;
@@ -598,15 +624,9 @@ static int live_hold_reset(void *arg)

/* We have our request executing, now remove it and reset */

- local_bh_disable();
- if (test_and_set_bit(I915_RESET_ENGINE + id,
- &gt->reset.flags)) {
- local_bh_enable();
- intel_gt_set_wedged(gt);
- err = -EBUSY;
+ err = engine_lock_reset_tasklet(engine);
+ if (err)
goto out;
- }
- tasklet_disable(&engine->execlists.tasklet);

engine->execlists.tasklet.callback(&engine->execlists.tasklet);
GEM_BUG_ON(execlists_active(&engine->execlists) != rq);
@@ -618,10 +638,7 @@ static int live_hold_reset(void *arg)
__intel_engine_reset_bh(engine, NULL);
GEM_BUG_ON(rq->fence.error != -EIO);

- tasklet_enable(&engine->execlists.tasklet);
- clear_and_wake_up_bit(I915_RESET_ENGINE + id,
- &gt->reset.flags);
- local_bh_enable();
+ engine_unlock_reset_tasklet(engine);

/* Check that we do not resubmit the held request */
if (!i915_request_wait(rq, 0, HZ / 5)) {
@@ -4585,15 +4602,9 @@ static int reset_virtual_engine(struct intel_gt *gt,
GEM_BUG_ON(engine == ve->engine);

/* Take ownership of the reset and tasklet */
- local_bh_disable();
- if (test_and_set_bit(I915_RESET_ENGINE + engine->id,
- &gt->reset.flags)) {
- local_bh_enable();
- intel_gt_set_wedged(gt);
- err = -EBUSY;
+ err = engine_lock_reset_tasklet(engine);
+ if (err)
goto out_heartbeat;
- }
- tasklet_disable(&engine->execlists.tasklet);

engine->execlists.tasklet.callback(&engine->execlists.tasklet);
GEM_BUG_ON(execlists_active(&engine->execlists) != rq);
@@ -4612,9 +4623,7 @@ static int reset_virtual_engine(struct intel_gt *gt,
GEM_BUG_ON(rq->fence.error != -EIO);

/* Release our grasp on the engine, letting CS flow again */
- tasklet_enable(&engine->execlists.tasklet);
- clear_and_wake_up_bit(I915_RESET_ENGINE + engine->id, &gt->reset.flags);
- local_bh_enable();
+ engine_unlock_reset_tasklet(engine);

/* Check that we do not resubmit the held request */
i915_request_get(rq);
--
2.30.2