Just some minor attempts at improving the readability of nouveau_fence.c This series is based on this partially merged series: [1] Feel free to drop single patches if they are not deemed worth the effort. P. [1] https://lore.kernel.org/dri-devel/20250415121900.55719-3-phasta at kernel.org/ Philipp Stanner (4): drm/nouveau: nouveau_fence: Standardize list iterations drm/nouveau: Simplify calls to nvif_event_block() drm/nouveau: Simplify nouveau_fence_done() drm/nouveau: Check dma_fence in canonical way drivers/gpu/drm/nouveau/nouveau_fence.c | 72 +++++++++++-------------- 1 file changed, 30 insertions(+), 42 deletions(-) -- 2.48.1
Philipp Stanner
2025-Apr-24 13:02 UTC
[PATCH 1/4] drm/nouveau: nouveau_fence: Standardize list iterations
nouveau_fence.c iterates over lists in a non-canonical way. Since the
operations done are just basic for-each-loops and list-empty checks,
they should be written in the standard form.
Use standard list operations.
Signed-off-by: Philipp Stanner <phasta at kernel.org>
---
drivers/gpu/drm/nouveau/nouveau_fence.c | 21 ++++++++-------------
1 file changed, 8 insertions(+), 13 deletions(-)
diff --git a/drivers/gpu/drm/nouveau/nouveau_fence.c
b/drivers/gpu/drm/nouveau/nouveau_fence.c
index 6ded8c2b6d3b..761c174cb286 100644
--- a/drivers/gpu/drm/nouveau/nouveau_fence.c
+++ b/drivers/gpu/drm/nouveau/nouveau_fence.c
@@ -83,13 +83,11 @@ nouveau_local_fence(struct dma_fence *fence, struct
nouveau_drm *drm)
void
nouveau_fence_context_kill(struct nouveau_fence_chan *fctx, int error)
{
- struct nouveau_fence *fence;
+ struct nouveau_fence *fence, *tmp;
unsigned long flags;
spin_lock_irqsave(&fctx->lock, flags);
- while (!list_empty(&fctx->pending)) {
- fence = list_entry(fctx->pending.next, typeof(*fence), head);
-
+ list_for_each_entry_safe(fence, tmp, &fctx->pending, head) {
if (error && !dma_fence_is_signaled_locked(&fence->base))
dma_fence_set_error(&fence->base, error);
@@ -130,13 +128,11 @@ nouveau_fence_context_free(struct nouveau_fence_chan
*fctx)
static int
nouveau_fence_update(struct nouveau_channel *chan, struct nouveau_fence_chan
*fctx)
{
- struct nouveau_fence *fence;
+ struct nouveau_fence *fence, *tmp;
int drop = 0;
u32 seq = fctx->read(chan);
- while (!list_empty(&fctx->pending)) {
- fence = list_entry(fctx->pending.next, typeof(*fence), head);
-
+ list_for_each_entry_safe(fence, tmp, &fctx->pending, head) {
if ((int)(seq - fence->base.seqno) < 0)
break;
@@ -151,15 +147,14 @@ nouveau_fence_uevent_work(struct work_struct *work)
{
struct nouveau_fence_chan *fctx = container_of(work, struct
nouveau_fence_chan,
uevent_work);
+ struct nouveau_channel *chan;
+ struct nouveau_fence *fence;
unsigned long flags;
int drop = 0;
spin_lock_irqsave(&fctx->lock, flags);
- if (!list_empty(&fctx->pending)) {
- struct nouveau_fence *fence;
- struct nouveau_channel *chan;
-
- fence = list_entry(fctx->pending.next, typeof(*fence), head);
+ fence = list_first_entry_or_null(&fctx->pending, typeof(*fence), head);
+ if (fence) {
chan = rcu_dereference_protected(fence->channel,
lockdep_is_held(&fctx->lock));
if (nouveau_fence_update(chan, fctx))
drop = 1;
--
2.48.1
Philipp Stanner
2025-Apr-24 13:02 UTC
[PATCH 2/4] drm/nouveau: Simplify calls to nvif_event_block()
nouveau_fence_signal() returns a de-facto boolean to indicate when
nvif_event_block() shall be called.
The code can be made more compact and readable by calling
nvif_event_block() in nouveau_fence_update() directly.
Make those calls in nouveau_fence.c more canonical.
Signed-off-by: Philipp Stanner <phasta at kernel.org>
---
drivers/gpu/drm/nouveau/nouveau_fence.c | 31 +++++++++++--------------
1 file changed, 13 insertions(+), 18 deletions(-)
diff --git a/drivers/gpu/drm/nouveau/nouveau_fence.c
b/drivers/gpu/drm/nouveau/nouveau_fence.c
index 761c174cb286..2b79bcb7da16 100644
--- a/drivers/gpu/drm/nouveau/nouveau_fence.c
+++ b/drivers/gpu/drm/nouveau/nouveau_fence.c
@@ -50,10 +50,10 @@ nouveau_fctx(struct nouveau_fence *fence)
return container_of(fence->base.lock, struct nouveau_fence_chan, lock);
}
-static int
+static bool
nouveau_fence_signal(struct nouveau_fence *fence)
{
- int drop = 0;
+ bool drop = false;
dma_fence_signal_locked(&fence->base);
list_del(&fence->head);
@@ -63,7 +63,7 @@ nouveau_fence_signal(struct nouveau_fence *fence)
struct nouveau_fence_chan *fctx = nouveau_fctx(fence);
if (!--fctx->notify_ref)
- drop = 1;
+ drop = true;
}
dma_fence_put(&fence->base);
@@ -125,21 +125,23 @@ nouveau_fence_context_free(struct nouveau_fence_chan
*fctx)
kref_put(&fctx->fence_ref, nouveau_fence_context_put);
}
-static int
+static void
nouveau_fence_update(struct nouveau_channel *chan, struct nouveau_fence_chan
*fctx)
{
struct nouveau_fence *fence, *tmp;
- int drop = 0;
+ bool drop = false;
u32 seq = fctx->read(chan);
list_for_each_entry_safe(fence, tmp, &fctx->pending, head) {
if ((int)(seq - fence->base.seqno) < 0)
break;
- drop |= nouveau_fence_signal(fence);
+ if (nouveau_fence_signal(fence))
+ drop = true;
}
- return drop;
+ if (drop)
+ nvif_event_block(&fctx->event);
}
static void
@@ -150,18 +152,13 @@ nouveau_fence_uevent_work(struct work_struct *work)
struct nouveau_channel *chan;
struct nouveau_fence *fence;
unsigned long flags;
- int drop = 0;
spin_lock_irqsave(&fctx->lock, flags);
fence = list_first_entry_or_null(&fctx->pending, typeof(*fence), head);
if (fence) {
chan = rcu_dereference_protected(fence->channel,
lockdep_is_held(&fctx->lock));
- if (nouveau_fence_update(chan, fctx))
- drop = 1;
+ nouveau_fence_update(chan, fctx);
}
- if (drop)
- nvif_event_block(&fctx->event);
-
spin_unlock_irqrestore(&fctx->lock, flags);
}
@@ -241,9 +238,7 @@ nouveau_fence_emit(struct nouveau_fence *fence)
return -ENODEV;
}
- if (nouveau_fence_update(chan, fctx))
- nvif_event_block(&fctx->event);
-
+ nouveau_fence_update(chan, fctx);
list_add_tail(&fence->head, &fctx->pending);
spin_unlock_irq(&fctx->lock);
}
@@ -265,8 +260,8 @@ nouveau_fence_done(struct nouveau_fence *fence)
spin_lock_irqsave(&fctx->lock, flags);
chan = rcu_dereference_protected(fence->channel,
lockdep_is_held(&fctx->lock));
- if (chan && nouveau_fence_update(chan, fctx))
- nvif_event_block(&fctx->event);
+ if (chan)
+ nouveau_fence_update(chan, fctx);
spin_unlock_irqrestore(&fctx->lock, flags);
}
return dma_fence_is_signaled(&fence->base);
--
2.48.1
Philipp Stanner
2025-Apr-24 13:02 UTC
[PATCH 3/4] drm/nouveau: Simplify nouveau_fence_done()
nouveau_fence_done() contains an if branch that checks whether a
nouveau_fence has either of the two existing nouveau_fence backend ops,
which will always evaluate to true.
Remove the surplus check.
Signed-off-by: Philipp Stanner <phasta at kernel.org>
---
drivers/gpu/drm/nouveau/nouveau_fence.c | 24 +++++++++++-------------
1 file changed, 11 insertions(+), 13 deletions(-)
diff --git a/drivers/gpu/drm/nouveau/nouveau_fence.c
b/drivers/gpu/drm/nouveau/nouveau_fence.c
index 2b79bcb7da16..fb9811938c82 100644
--- a/drivers/gpu/drm/nouveau/nouveau_fence.c
+++ b/drivers/gpu/drm/nouveau/nouveau_fence.c
@@ -249,21 +249,19 @@ nouveau_fence_emit(struct nouveau_fence *fence)
bool
nouveau_fence_done(struct nouveau_fence *fence)
{
- if (fence->base.ops == &nouveau_fence_ops_legacy ||
- fence->base.ops == &nouveau_fence_ops_uevent) {
- struct nouveau_fence_chan *fctx = nouveau_fctx(fence);
- struct nouveau_channel *chan;
- unsigned long flags;
+ struct nouveau_fence_chan *fctx = nouveau_fctx(fence);
+ struct nouveau_channel *chan;
+ unsigned long flags;
- if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->base.flags))
- return true;
+ if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->base.flags))
+ return true;
+
+ spin_lock_irqsave(&fctx->lock, flags);
+ chan = rcu_dereference_protected(fence->channel,
lockdep_is_held(&fctx->lock));
+ if (chan)
+ nouveau_fence_update(chan, fctx);
+ spin_unlock_irqrestore(&fctx->lock, flags);
- spin_lock_irqsave(&fctx->lock, flags);
- chan = rcu_dereference_protected(fence->channel,
lockdep_is_held(&fctx->lock));
- if (chan)
- nouveau_fence_update(chan, fctx);
- spin_unlock_irqrestore(&fctx->lock, flags);
- }
return dma_fence_is_signaled(&fence->base);
}
--
2.48.1
Philipp Stanner
2025-Apr-24 13:02 UTC
[PATCH 4/4] drm/nouveau: Check dma_fence in canonical way
In nouveau_fence_done(), a fence is checked for being signaled by manually evaluating the base fence's bits. This can be done in a canonical manner through dma_fence_is_signaled(). Replace the bit-check with dma_fence_is_signaled(). Signed-off-by: Philipp Stanner <phasta at kernel.org> --- drivers/gpu/drm/nouveau/nouveau_fence.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/nouveau/nouveau_fence.c b/drivers/gpu/drm/nouveau/nouveau_fence.c index fb9811938c82..d5654e26d5bc 100644 --- a/drivers/gpu/drm/nouveau/nouveau_fence.c +++ b/drivers/gpu/drm/nouveau/nouveau_fence.c @@ -253,7 +253,7 @@ nouveau_fence_done(struct nouveau_fence *fence) struct nouveau_channel *chan; unsigned long flags; - if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->base.flags)) + if (dma_fence_is_signaled(&fence->base)) return true; spin_lock_irqsave(&fctx->lock, flags); -- 2.48.1