From 76bf0db5543976ef50362db7071da367cb118532 Mon Sep 17 00:00:00 2001 From: Christian König Date: Wed, 1 Jun 2016 15:10:02 +0200 Subject: dma-buf/fence: make fence context 64 bit v2 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Fence contexts are created on the fly (for example) by the GPU scheduler used in the amdgpu driver as a result of an userspace request. Because of this userspace could in theory force a wrap around of the 32bit context number if it doesn't behave well. Avoid this by increasing the context number to 64bits. This way even when userspace manages to allocate a billion contexts per second it takes more than 500 years for the context number to wrap around. v2: fix printf formats as well. Signed-off-by: Christian König Reviewed-by: Gustavo Padovan Acked-by: Sumit Semwal Signed-off-by: Daniel Vetter Link: http://patchwork.freedesktop.org/patch/msgid/1464786612-5010-2-git-send-email-deathsimple@vodafone.de --- drivers/dma-buf/fence.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'drivers/dma-buf') diff --git a/drivers/dma-buf/fence.c b/drivers/dma-buf/fence.c index 7b05dbe9b296..4d51f9e83fa8 100644 --- a/drivers/dma-buf/fence.c +++ b/drivers/dma-buf/fence.c @@ -35,7 +35,7 @@ EXPORT_TRACEPOINT_SYMBOL(fence_emit); * context or not. One device can have multiple separate contexts, * and they're used if some engine can run independently of another. */ -static atomic_t fence_context_counter = ATOMIC_INIT(0); +static atomic64_t fence_context_counter = ATOMIC64_INIT(0); /** * fence_context_alloc - allocate an array of fence contexts @@ -44,10 +44,10 @@ static atomic_t fence_context_counter = ATOMIC_INIT(0); * This function will return the first index of the number of fences allocated. * The fence context is used for setting fence->context to a unique number. */ -unsigned fence_context_alloc(unsigned num) +u64 fence_context_alloc(unsigned num) { BUG_ON(!num); - return atomic_add_return(num, &fence_context_counter) - num; + return atomic64_add_return(num, &fence_context_counter) - num; } EXPORT_SYMBOL(fence_context_alloc); @@ -513,7 +513,7 @@ EXPORT_SYMBOL(fence_wait_any_timeout); */ void fence_init(struct fence *fence, const struct fence_ops *ops, - spinlock_t *lock, unsigned context, unsigned seqno) + spinlock_t *lock, u64 context, unsigned seqno) { BUG_ON(!lock); BUG_ON(!ops || !ops->wait || !ops->enable_signaling || -- cgit v1.2.3