Am 02.08.22 um 23:01 schrieb Jason Ekstrand:
Ever since 68129f431faa ("dma-buf: warn about containers in dma_resv object"),
dma_resv_add_shared_fence will warn if you attempt to add a container fence.
While most drivers were fine, fences can also be added to a dma_resv via the
recently added DMA_BUF_IOCTL_IMPORT_SYNC_FILE. Use dma_fence_unwrap_for_each
to add each fence one at a time.
Fixes: 594740497e99 ("dma-buf: Add an API for importing sync files (v10)")
Signed-off-by: Jason Ekstrand <jason.ekstrand@xxxxxxxxxxxxx>
Reported-by: Sarah Walker <Sarah.Walker@xxxxxxxxxx>
Cc: Christian König <christian.koenig@xxxxxxx>
---
drivers/dma-buf/dma-buf.c | 23 +++++++++++++++++------
1 file changed, 17 insertions(+), 6 deletions(-)
diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index 630133284e2b..8d5d45112f52 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -15,6 +15,7 @@
#include <linux/slab.h>
#include <linux/dma-buf.h>
#include <linux/dma-fence.h>
+#include <linux/dma-fence-unwrap.h>
#include <linux/anon_inodes.h>
#include <linux/export.h>
#include <linux/debugfs.h>
@@ -391,8 +392,10 @@ static long dma_buf_import_sync_file(struct dma_buf *dmabuf,
const void __user *user_data)
{
struct dma_buf_import_sync_file arg;
- struct dma_fence *fence;
+ struct dma_fence *fence, *f;
enum dma_resv_usage usage;
+ struct dma_fence_unwrap iter;
+ unsigned int num_fences;
int ret = 0;
if (copy_from_user(&arg, user_data, sizeof(arg)))
@@ -411,13 +414,21 @@ static long dma_buf_import_sync_file(struct dma_buf *dmabuf,
usage = (arg.flags & DMA_BUF_SYNC_WRITE) ? DMA_RESV_USAGE_WRITE :
DMA_RESV_USAGE_READ;
- dma_resv_lock(dmabuf->resv, NULL);
+ num_fences = 0;
+ dma_fence_unwrap_for_each(f, &iter, fence)
+ ++num_fences;
- ret = dma_resv_reserve_fences(dmabuf->resv, 1);
- if (!ret)
- dma_resv_add_fence(dmabuf->resv, fence, usage);
+ if (num_fences > 0) {
+ dma_resv_lock(dmabuf->resv, NULL);
- dma_resv_unlock(dmabuf->resv);
+ ret = dma_resv_reserve_fences(dmabuf->resv, num_fences);
That looks like it is misplaced.
You *must* only lock the reservation object once and then add all fences
in one go.
Thinking now about it we probably had a bug around that before as well.
Going to double check tomorrow.
Regards,
Christian.
+ if (!ret) {
+ dma_fence_unwrap_for_each(f, &iter, fence)
+ dma_resv_add_fence(dmabuf->resv, f, usage);
+ }
+
+ dma_resv_unlock(dmabuf->resv);
+ }
dma_fence_put(fence);
