dma-buf: add dma_fence_chain_alloc/free v3

Add a common allocation helper. Cleaning up the mix of kzalloc/kmalloc
and some unused code in the selftest.

v2: polish kernel doc a bit
v3: polish kernel doc even a bit more

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210611120301.10595-3-christian.koenig@amd.com

diff --git a/drivers/dma-buf/st-dma-fence-chain.c b/drivers/dma-buf/st-dma-fence-chain.c
index 9525f7f..8ce1ea5 100644 (file)
--- a/drivers/dma-buf/st-dma-fence-chain.c
+++ b/drivers/dma-buf/st-dma-fence-chain.c
@@ -58,28 +58,20 @@ static struct dma_fence *mock_fence(void)
        return &f->base;
 }
 
-static inline struct mock_chain {
-       struct dma_fence_chain base;
-} *to_mock_chain(struct dma_fence *f) {
-       return container_of(f, struct mock_chain, base.base);
-}
-
 static struct dma_fence *mock_chain(struct dma_fence *prev,
                                    struct dma_fence *fence,
                                    u64 seqno)
 {
-       struct mock_chain *f;
+       struct dma_fence_chain *f;
 
-       f = kmalloc(sizeof(*f), GFP_KERNEL);
+       f = dma_fence_chain_alloc();
        if (!f)
                return NULL;
 
-       dma_fence_chain_init(&f->base,
-                            dma_fence_get(prev),
-                            dma_fence_get(fence),
+       dma_fence_chain_init(f, dma_fence_get(prev), dma_fence_get(fence),
                             seqno);
 
-       return &f->base.base;
+       return &f->base;
 }
 
 static int sanitycheck(void *arg)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
index 1476236..9ce649a 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
@@ -1109,7 +1109,7 @@ static int amdgpu_cs_process_syncobj_timeline_out_dep(struct amdgpu_cs_parser *p
 
                dep->chain = NULL;
                if (syncobj_deps[i].point) {
-                       dep->chain = kmalloc(sizeof(*dep->chain), GFP_KERNEL);
+                       dep->chain = dma_fence_chain_alloc();
                        if (!dep->chain)
                                return -ENOMEM;
                }
@@ -1117,7 +1117,7 @@ static int amdgpu_cs_process_syncobj_timeline_out_dep(struct amdgpu_cs_parser *p
                dep->syncobj = drm_syncobj_find(p->filp,
                                                syncobj_deps[i].handle);
                if (!dep->syncobj) {
-                       kfree(dep->chain);
+                       dma_fence_chain_free(dep->chain);
                        return -EINVAL;
                }
                dep->point = syncobj_deps[i].point;

diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c
index fdd2ec8..1c5b9ef 100644 (file)
--- a/drivers/gpu/drm/drm_syncobj.c
+++ b/drivers/gpu/drm/drm_syncobj.c
@@ -861,7 +861,7 @@ static int drm_syncobj_transfer_to_timeline(struct drm_file *file_private,
                                     &fence);
        if (ret)
                goto err;
-       chain = kzalloc(sizeof(struct dma_fence_chain), GFP_KERNEL);
+       chain = dma_fence_chain_alloc();
        if (!chain) {
                ret = -ENOMEM;
                goto err1;
@@ -1402,10 +1402,10 @@ drm_syncobj_timeline_signal_ioctl(struct drm_device *dev, void *data,
                goto err_points;
        }
        for (i = 0; i < args->count_handles; i++) {
-               chains[i] = kzalloc(sizeof(struct dma_fence_chain), GFP_KERNEL);
+               chains[i] = dma_fence_chain_alloc();
                if (!chains[i]) {
                        for (j = 0; j < i; j++)
-                               kfree(chains[j]);
+                               dma_fence_chain_free(chains[j]);
                        ret = -ENOMEM;
                        goto err_chains;
                }

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
index a8abc9a..8e195fa 100644 (file)
--- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
@@ -2983,7 +2983,7 @@ __free_fence_array(struct eb_fence *fences, unsigned int n)
        while (n--) {
                drm_syncobj_put(ptr_mask_bits(fences[n].syncobj, 2));
                dma_fence_put(fences[n].dma_fence);
-               kfree(fences[n].chain_fence);
+               dma_fence_chain_free(fences[n].chain_fence);
        }
        kvfree(fences);
 }
@@ -3097,9 +3097,7 @@ add_timeline_fence_array(struct i915_execbuffer *eb,
                                return -EINVAL;
                        }
 
-                       f->chain_fence =
-                               kmalloc(sizeof(*f->chain_fence),
-                                       GFP_KERNEL);
+                       f->chain_fence = dma_fence_chain_alloc();
                        if (!f->chain_fence) {
                                drm_syncobj_put(syncobj);
                                dma_fence_put(fence);

diff --git a/drivers/gpu/drm/msm/msm_gem_submit.c b/drivers/gpu/drm/msm/msm_gem_submit.c
index 5480852..6ff6df6 100644 (file)
--- a/drivers/gpu/drm/msm/msm_gem_submit.c
+++ b/drivers/gpu/drm/msm/msm_gem_submit.c
@@ -586,9 +586,7 @@ static struct msm_submit_post_dep *msm_parse_post_deps(struct drm_device *dev,
                                break;
                        }
 
-                       post_deps[i].chain =
-                               kmalloc(sizeof(*post_deps[i].chain),
-                                       GFP_KERNEL);
+                       post_deps[i].chain = dma_fence_chain_alloc();
                        if (!post_deps[i].chain) {
                                ret = -ENOMEM;
                                break;
@@ -605,7 +603,7 @@ static struct msm_submit_post_dep *msm_parse_post_deps(struct drm_device *dev,
 
        if (ret) {
                for (j = 0; j <= i; ++j) {
-                       kfree(post_deps[j].chain);
+                       dma_fence_chain_free(post_deps[j].chain);
                        if (post_deps[j].syncobj)
                                drm_syncobj_put(post_deps[j].syncobj);
                }

diff --git a/include/linux/dma-fence-chain.h b/include/linux/dma-fence-chain.h
index c6eb3aa..54fe344 100644 (file)
--- a/include/linux/dma-fence-chain.h
+++ b/include/linux/dma-fence-chain.h
@@ -12,6 +12,7 @@
 
 #include <linux/dma-fence.h>
 #include <linux/irq_work.h>
+#include <linux/slab.h>
 
 /**
  * struct dma_fence_chain - fence to represent an node of a fence chain
@@ -67,6 +68,30 @@ to_dma_fence_chain(struct dma_fence *fence)
 }
 
 /**
+ * dma_fence_chain_alloc
+ *
+ * Returns a new struct dma_fence_chain object or NULL on failure.
+ */
+static inline struct dma_fence_chain *dma_fence_chain_alloc(void)
+{
+       return kmalloc(sizeof(struct dma_fence_chain), GFP_KERNEL);
+};
+
+/**
+ * dma_fence_chain_free
+ * @chain: chain node to free
+ *
+ * Frees up an allocated but not used struct dma_fence_chain object. This
+ * doesn't need an RCU grace period since the fence was never initialized nor
+ * published. After dma_fence_chain_init() has been called the fence must be
+ * released by calling dma_fence_put(), and not through this function.
+ */
+static inline void dma_fence_chain_free(struct dma_fence_chain *chain)
+{
+       kfree(chain);
+};
+
+/**
  * dma_fence_chain_for_each - iterate over all fences in chain
  * @iter: current fence
  * @head: starting point