| Message ID | 20190810153430.30636-4-chris@chris-wilson.co.uk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/4] dma-fence: Propagate errors to dma-fence-array container | expand |
Am 10.08.19 um 17:34 schrieb Chris Wilson: > Allow for some users to surreptitiously insert lazy signal callbacks that > do not depend on enabling the signaling mechanism around every fence. > (The cost of interrupts is too darn high, to revive an old meme.) > This means that we may have a cb_list even if the signaling bit is not > enabled, so always notify the callbacks. > > The cost is that dma_fence_signal() must always acquire the spinlock to > ensure that the cb_list is flushed. > > Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> > --- > drivers/dma-buf/dma-fence.c | 8 +++----- > 1 file changed, 3 insertions(+), 5 deletions(-) > > diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c > index 027a6a894abd..ab4a456bba04 100644 > --- a/drivers/dma-buf/dma-fence.c > +++ b/drivers/dma-buf/dma-fence.c > @@ -170,11 +170,9 @@ int dma_fence_signal(struct dma_fence *fence) > > __dma_fence_signal__timestamp(fence, ktime_get()); > > - if (test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, &fence->flags)) { > - spin_lock_irqsave(fence->lock, flags); > - __dma_fence_signal__notify(fence); > - spin_unlock_irqrestore(fence->lock, flags); > - } > + spin_lock_irqsave(fence->lock, flags); > + __dma_fence_signal__notify(fence); > + spin_unlock_irqrestore(fence->lock, flags); If we now always grab the spinlock anyway I suggest to rather merge dma_fence_signal and dma_fence_signal_locked. Christian. > return 0; > } > EXPORT_SYMBOL(dma_fence_signal);
diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c index 027a6a894abd..ab4a456bba04 100644 --- a/drivers/dma-buf/dma-fence.c +++ b/drivers/dma-buf/dma-fence.c @@ -170,11 +170,9 @@ int dma_fence_signal(struct dma_fence *fence) __dma_fence_signal__timestamp(fence, ktime_get()); - if (test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, &fence->flags)) { - spin_lock_irqsave(fence->lock, flags); - __dma_fence_signal__notify(fence); - spin_unlock_irqrestore(fence->lock, flags); - } + spin_lock_irqsave(fence->lock, flags); + __dma_fence_signal__notify(fence); + spin_unlock_irqrestore(fence->lock, flags); return 0; } EXPORT_SYMBOL(dma_fence_signal);
Allow for some users to surreptitiously insert lazy signal callbacks that do not depend on enabling the signaling mechanism around every fence. (The cost of interrupts is too darn high, to revive an old meme.) This means that we may have a cb_list even if the signaling bit is not enabled, so always notify the callbacks. The cost is that dma_fence_signal() must always acquire the spinlock to ensure that the cb_list is flushed. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> --- drivers/dma-buf/dma-fence.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-)