<div dir="ltr"><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Mon, Aug 8, 2022 at 11:39 AM Jason Ekstrand <<a href="mailto:jason.ekstrand@collabora.com">jason.ekstrand@collabora.com</a>> wrote: </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">On Sun, 2022-08-07 at 18:35 +0200, Christian König wrote: > 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 <<a href="mailto:jason.ekstrand@collabora.com" target="_blank">jason.ekstrand@collabora.com</a>> > > Reported-by: Sarah Walker <<a href="mailto:Sarah.Walker@imgtec.com" target="_blank">Sarah.Walker@imgtec.com</a>> > > Cc: Christian König <<a href="mailto:christian.koenig@amd.com" target="_blank">christian.koenig@amd.com</a>> > > --- > > 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. That's what I'm doing. Lock, reserve, add a bunch, unlock. I am assuming that the iterator won't suddenly want to iterate more fences between my initial count and when I go to add them but I think that assumption is ok. </blockquote><div> </div><div>Bump. This has been sitting here for a couple of weeks. I still don't see the problem.</div><div> </div><div>--Jason </div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"> --Jason > 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); > > > </blockquote></div></div>