From: Dave Airlie airlied@redhat.com
This isn't needed currently, but to reuse sync file for Vulkan permanent shared semaphore semantics, we need to be able to swap the fence backing a sync file. This patch adds a mutex to the sync file and uses to protect accesses to the fence and cb members.
Signed-off-by: Dave Airlie airlied@redhat.com --- drivers/dma-buf/sync_file.c | 23 +++++++++++++++++++---- include/linux/sync_file.h | 3 +++ 2 files changed, 22 insertions(+), 4 deletions(-)
diff --git a/drivers/dma-buf/sync_file.c b/drivers/dma-buf/sync_file.c index 2321035..105f48c 100644 --- a/drivers/dma-buf/sync_file.c +++ b/drivers/dma-buf/sync_file.c @@ -47,6 +47,7 @@ static struct sync_file *sync_file_alloc(void)
INIT_LIST_HEAD(&sync_file->cb.node);
+ mutex_init(&sync_file->lock); return sync_file;
err: @@ -204,10 +205,13 @@ static struct sync_file *sync_file_merge(const char *name, struct sync_file *a, if (!sync_file) return NULL;
+ mutex_lock(&a->lock); + mutex_lock(&b->lock); a_fences = get_fences(a, &a_num_fences); b_fences = get_fences(b, &b_num_fences); - if (a_num_fences > INT_MAX - b_num_fences) - return NULL; + if (a_num_fences > INT_MAX - b_num_fences) { + goto unlock; + }
num_fences = a_num_fences + b_num_fences;
@@ -268,11 +272,17 @@ static struct sync_file *sync_file_merge(const char *name, struct sync_file *a, goto err; }
+ mutex_unlock(&b->lock); + mutex_unlock(&a->lock); + strlcpy(sync_file->name, name, sizeof(sync_file->name)); return sync_file;
err: fput(sync_file->file); +unlock: + mutex_unlock(&b->lock); + mutex_unlock(&a->lock); return NULL;
} @@ -299,16 +309,20 @@ static int sync_file_release(struct inode *inode, struct file *file) static unsigned int sync_file_poll(struct file *file, poll_table *wait) { struct sync_file *sync_file = file->private_data; + unsigned int ret_val;
poll_wait(file, &sync_file->wq, wait);
+ mutex_lock(&sync_file->lock); if (!test_and_set_bit(POLL_ENABLED, &sync_file->fence->flags)) { if (dma_fence_add_callback(sync_file->fence, &sync_file->cb, fence_check_cb_func) < 0) wake_up_all(&sync_file->wq); } + ret_val = dma_fence_is_signaled(sync_file->fence) ? POLLIN : 0; + mutex_unlock(&sync_file->lock);
- return dma_fence_is_signaled(sync_file->fence) ? POLLIN : 0; + return ret_val; }
static long sync_file_ioctl_merge(struct sync_file *sync_file, @@ -393,6 +407,7 @@ static long sync_file_ioctl_fence_info(struct sync_file *sync_file, if (info.flags || info.pad) return -EINVAL;
+ mutex_lock(&sync_file->lock); fences = get_fences(sync_file, &num_fences);
/* @@ -433,7 +448,7 @@ static long sync_file_ioctl_fence_info(struct sync_file *sync_file,
out: kfree(fence_info); - + mutex_unlock(&sync_file->lock); return ret; }
diff --git a/include/linux/sync_file.h b/include/linux/sync_file.h index 3e3ab84..5aef17f 100644 --- a/include/linux/sync_file.h +++ b/include/linux/sync_file.h @@ -30,6 +30,7 @@ * @wq: wait queue for fence signaling * @fence: fence with the fences in the sync_file * @cb: fence callback information + * @lock: mutex to protect fence/cb - used for semaphores */ struct sync_file { struct file *file; @@ -43,6 +44,8 @@ struct sync_file {
struct dma_fence *fence; struct dma_fence_cb cb; + /* protects the fence pointer and cb */ + struct mutex lock; };
#define POLL_ENABLED DMA_FENCE_FLAG_USER_BITS