dma-buf/fence: make fence context 64 bit v2

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 <christian.koenig@amd.com>
Reviewed-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Acked-by: Sumit Semwal <sumit.semwal@linaro.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1464786612-5010-2-git-send-email-deathsimple@vodafone.de

10 files changed, 21 insertions, 18 deletions

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 ||
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index 992f00b65be4..da3d02154fa6 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -2032,7 +2032,7 @@ struct amdgpu_device {
         struct amdgpu_irq_src           hpd_irq;
 
         /* rings */
-        unsigned                        fence_context;
+        u64                             fence_context;
         unsigned                        num_rings;
         struct amdgpu_ring              *rings[AMDGPU_MAX_RINGS];
         bool                            ib_pool_ready;
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_sa.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_sa.c
index 8bf84efafb04..b16366c2b4a0 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_sa.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_sa.c
@@ -427,7 +427,7 @@ void amdgpu_sa_bo_dump_debug_info(struct amdgpu_sa_manager *sa_manager,
                            soffset, eoffset, eoffset - soffset);
 
                 if (i->fence)
-                        seq_printf(m, " protected by 0x%08x on context %d",
+                        seq_printf(m, " protected by 0x%08x on context %llu",
                                    i->fence->seqno, i->fence->context);
 
                 seq_printf(m, "\n");
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gpu.h b/drivers/gpu/drm/etnaviv/etnaviv_gpu.h
index f5321e2f25ff..a69cdd526bf8 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.h
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.h
@@ -125,7 +125,7 @@ struct etnaviv_gpu {
         u32 completed_fence;
         u32 retired_fence;
         wait_queue_head_t fence_event;
-        unsigned int fence_context;
+        u64 fence_context;
         spinlock_t fence_spinlock;
 
         /* worker for handling active-list retiring: */
diff --git a/drivers/gpu/drm/nouveau/nouveau_fence.h b/drivers/gpu/drm/nouveau/nouveau_fence.h
index 2e3a62d38fe9..64c4ce7115ad 100644
--- a/drivers/gpu/drm/nouveau/nouveau_fence.h
+++ b/drivers/gpu/drm/nouveau/nouveau_fence.h
@@ -57,7 +57,8 @@ struct nouveau_fence_priv {
         int  (*context_new)(struct nouveau_channel *);
         void (*context_del)(struct nouveau_channel *);
 
-        u32 contexts, context_base;
+        u32 contexts;
+        u64 context_base;
         bool uevent;
 };
 
diff --git a/drivers/gpu/drm/qxl/qxl_release.c b/drivers/gpu/drm/qxl/qxl_release.c
index 4efa8e261baf..f599cd073b72 100644
--- a/drivers/gpu/drm/qxl/qxl_release.c
+++ b/drivers/gpu/drm/qxl/qxl_release.c
@@ -96,7 +96,7 @@ retry:
                         return 0;
 
                 if (have_drawable_releases && sc > 300) {
-                        FENCE_WARN(fence, "failed to wait on release %d "
+                        FENCE_WARN(fence, "failed to wait on release %llu "
                                           "after spincount %d\n",
                                           fence->context & ~0xf0000000, sc);
                         goto signaled;
diff --git a/drivers/gpu/drm/radeon/radeon.h b/drivers/gpu/drm/radeon/radeon.h
index 80b24a495d6c..5633ee3eb46e 100644
--- a/drivers/gpu/drm/radeon/radeon.h
+++ b/drivers/gpu/drm/radeon/radeon.h
@@ -2386,7 +2386,7 @@ struct radeon_device {
         struct radeon_mman              mman;
         struct radeon_fence_driver      fence_drv[RADEON_NUM_RINGS];
         wait_queue_head_t               fence_queue;
-        unsigned                        fence_context;
+        u64                             fence_context;
         struct mutex                    ring_lock;
         struct radeon_ring              ring[RADEON_NUM_RINGS];
         bool                            ib_pool_ready;
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c b/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c
index e959df6ede83..26ac8e80a478 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c
@@ -46,7 +46,7 @@ struct vmw_fence_manager {
         bool goal_irq_on; /* Protected by @goal_irq_mutex */
         bool seqno_valid; /* Protected by @lock, and may not be set to true
                              without the @goal_irq_mutex held. */
-        unsigned ctx;
+        u64 ctx;
 };
 
 struct vmw_user_fence {
diff --git a/drivers/staging/android/sync.h b/drivers/staging/android/sync.h
index b56885c14839..ebb34dca60df 100644
--- a/drivers/staging/android/sync.h
+++ b/drivers/staging/android/sync.h
@@ -68,7 +68,8 @@ struct sync_timeline {
 
         /* protected by child_list_lock */
         bool                    destroyed;
-        int                     context, value;
+        u64                     context;
+        int                     value;
 
         struct list_head        child_list_head;
         spinlock_t              child_list_lock;
diff --git a/include/linux/fence.h b/include/linux/fence.h
index 2b17698b60b8..18a97c6b79db 100644
--- a/include/linux/fence.h
+++ b/include/linux/fence.h
@@ -75,7 +75,8 @@ struct fence {
         struct rcu_head rcu;
         struct list_head cb_list;
         spinlock_t *lock;
-        unsigned context, seqno;
+        u64 context;
+        unsigned seqno;
         unsigned long flags;
         ktime_t timestamp;
         int status;
@@ -178,7 +179,7 @@ struct fence_ops {
 };
 
 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);
 
 void fence_release(struct kref *kref);
 void fence_free(struct fence *fence);
@@ -352,27 +353,27 @@ static inline signed long fence_wait(struct fence *fence, bool intr)
         return ret < 0 ? ret : 0;
 }
 
-unsigned fence_context_alloc(unsigned num);
+u64 fence_context_alloc(unsigned num);
 
 #define FENCE_TRACE(f, fmt, args...) \
         do {                                                            \
                 struct fence *__ff = (f);                               \
                 if (config_enabled(CONFIG_FENCE_TRACE))                 \
-                        pr_info("f %u#%u: " fmt,                        \
+                        pr_info("f %llu#%u: " fmt,                      \
                                 __ff->context, __ff->seqno, ##args);    \
         } while (0)
 
 #define FENCE_WARN(f, fmt, args...) \
         do {                                                            \
                 struct fence *__ff = (f);                               \
-                pr_warn("f %u#%u: " fmt, __ff->context, __ff->seqno,    \
+                pr_warn("f %llu#%u: " fmt, __ff->context, __ff->seqno,  \
                          ##args);                                       \
         } while (0)
 
 #define FENCE_ERR(f, fmt, args...) \
         do {                                                            \
                 struct fence *__ff = (f);                               \
-                pr_err("f %u#%u: " fmt, __ff->context, __ff->seqno,     \
+                pr_err("f %llu#%u: " fmt, __ff->context, __ff->seqno,   \
                         ##args);                                        \
         } while (0)