Nouveau - Nov 2018 - [PATCH -next] drm/nouveau: fix copy-paste error in nouveau_fence_wait_uevent_handler

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/gpu/drm/nouveau/nouveau_fence.c: In function
'nouveau_fence_wait_uevent_handler':
drivers/gpu/drm/nouveau/nouveau_fence.c:156:27: warning:
 variable 'chan' set but not used [-Wunused-but-set-variable]

nouveau_fence_update should use rcu protected 'chan'
rather than 'fence->channel'

Fixes: 0ec5f02f0e2c ("drm/nouveau: prevent stale fence->channel
pointers, and protect with rcu")
Signed-off-by: YueHaibing <yuehaibing at huawei.com>
---
 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 d4964f3..91286d0 100644
--- a/drivers/gpu/drm/nouveau/nouveau_fence.c
+++ b/drivers/gpu/drm/nouveau/nouveau_fence.c
@@ -157,7 +157,7 @@
 
 		fence = list_entry(fctx->pending.next, typeof(*fence), head);
 		chan = rcu_dereference_protected(fence->channel,
lockdep_is_held(&fctx->lock));
-		if (nouveau_fence_update(fence->channel, fctx))
+		if (nouveau_fence_update(chan, fctx))
 			ret = NVIF_NOTIFY_DROP;
 	}
 	spin_unlock_irqrestore(&fctx->lock, flags);

Friendly ping, Ben.
I see that in `nouveau_fence_done()` there is a check on `chan` not being NULL
prior to passing it to `nouveau_fence_update()`. Would something similar be
needed here?

Pierre

On 2018-11-15 — 12:14, YueHaibing wrote:
> Fixes gcc '-Wunused-but-set-variable' warning:
> 
> drivers/gpu/drm/nouveau/nouveau_fence.c: In function
'nouveau_fence_wait_uevent_handler':
> drivers/gpu/drm/nouveau/nouveau_fence.c:156:27: warning:
>  variable 'chan' set but not used [-Wunused-but-set-variable]
> 
> nouveau_fence_update should use rcu protected 'chan'
> rather than 'fence->channel'
> 
> Fixes: 0ec5f02f0e2c ("drm/nouveau: prevent stale fence->channel
pointers, and protect with rcu")
> Signed-off-by: YueHaibing <yuehaibing at huawei.com>
> ---
>  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 d4964f3..91286d0 100644
> --- a/drivers/gpu/drm/nouveau/nouveau_fence.c
> +++ b/drivers/gpu/drm/nouveau/nouveau_fence.c
> @@ -157,7 +157,7 @@
>  
>  		fence = list_entry(fctx->pending.next, typeof(*fence), head);
>  		chan = rcu_dereference_protected(fence->channel,
lockdep_is_held(&fctx->lock));
> -		if (nouveau_fence_update(fence->channel, fctx))
> +		if (nouveau_fence_update(chan, fctx))
>  			ret = NVIF_NOTIFY_DROP;
>  	}
>  	spin_unlock_irqrestore(&fctx->lock, flags);
> 
> 
> 
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