Hi Peter,
On Thu, Jul 09, 2020 at 04:07:38PM +0300, Peter Ujfalusi wrote:
> On 08/07/2020 23.19, Laurent Pinchart wrote:
> > A few virt-dma functions are documented as requiring the vc.lock to be
> > held by the caller. Check this with lockdep.
> >
> > The vchan_vdesc_fini() and vchan_find_desc() functions gain a lockdep
>
> vchan_vdesc_fini() is used outside of held vc->lock via vchan_complete()
> and the customized local re-implementation of it in ti/k3-udma.c
>
> This patch did not adds the lockdep_assert_held() to the _fini.
> The vchan_complete() can be issue only in case when the descriptor is
> set to DMA_CTRL_REUSE.
I'll drop the patch completely, I don't need it for this series. I still
think it's useful though, so if someone wants to pick it up and fix it,
please don't hesitate.
> > check as well, because, even though they are not documented with this
> > requirement (and not documented at all for the latter), they touch
> > fields documented as protected by vc.lock. All callers have been
> > manually inspected to verify they call the functions with the lock held.
> >
> > Signed-off-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> > ---
> > drivers/dma/virt-dma.c | 2 ++
> > drivers/dma/virt-dma.h | 10 ++++++++++
> > 2 files changed, 12 insertions(+)
> >
> > diff --git a/drivers/dma/virt-dma.c b/drivers/dma/virt-dma.c
> > index 23e33a85f033..1cb36ab3d9c1 100644
> > --- a/drivers/dma/virt-dma.c
> > +++ b/drivers/dma/virt-dma.c
> > @@ -68,6 +68,8 @@ struct virt_dma_desc *vchan_find_desc(struct virt_dma_chan *vc,
> > {
> > struct virt_dma_desc *vd;
> >
> > + lockdep_assert_held(&vc->lock);
> > +
> > list_for_each_entry(vd, &vc->desc_issued, node)
> > if (vd->tx.cookie == cookie)
> > return vd;
> > diff --git a/drivers/dma/virt-dma.h b/drivers/dma/virt-dma.h
> > index e9f5250fbe4d..59d9eabc8b67 100644
> > --- a/drivers/dma/virt-dma.h
> > +++ b/drivers/dma/virt-dma.h
> > @@ -81,6 +81,8 @@ static inline struct dma_async_tx_descriptor *vchan_tx_prep(struct virt_dma_chan
> > */
> > static inline bool vchan_issue_pending(struct virt_dma_chan *vc)
> > {
> > + lockdep_assert_held(&vc->lock);
> > +
> > list_splice_tail_init(&vc->desc_submitted, &vc->desc_issued);
> > return !list_empty(&vc->desc_issued);
> > }
> > @@ -96,6 +98,8 @@ static inline void vchan_cookie_complete(struct virt_dma_desc *vd)
> > struct virt_dma_chan *vc = to_virt_chan(vd->tx.chan);
> > dma_cookie_t cookie;
> >
> > + lockdep_assert_held(&vc->lock);
> > +
> > cookie = vd->tx.cookie;
> > dma_cookie_complete(&vd->tx);
> > dev_vdbg(vc->chan.device->dev, "txd %p[%x]: marked complete\n",
> > @@ -146,6 +150,8 @@ static inline void vchan_terminate_vdesc(struct virt_dma_desc *vd)
> > {
> > struct virt_dma_chan *vc = to_virt_chan(vd->tx.chan);
> >
> > + lockdep_assert_held(&vc->lock);
> > +
> > list_add_tail(&vd->node, &vc->desc_terminated);
> >
> > if (vc->cyclic == vd)
> > @@ -160,6 +166,8 @@ static inline void vchan_terminate_vdesc(struct virt_dma_desc *vd)
> > */
> > static inline struct virt_dma_desc *vchan_next_desc(struct virt_dma_chan *vc)
> > {
> > + lockdep_assert_held(&vc->lock);
> > +
> > return list_first_entry_or_null(&vc->desc_issued,
> > struct virt_dma_desc, node);
> > }
> > @@ -177,6 +185,8 @@ static inline struct virt_dma_desc *vchan_next_desc(struct virt_dma_chan *vc)
> > static inline void vchan_get_all_descriptors(struct virt_dma_chan *vc,
> > struct list_head *head)
> > {
> > + lockdep_assert_held(&vc->lock);
> > +
> > list_splice_tail_init(&vc->desc_allocated, head);
> > list_splice_tail_init(&vc->desc_submitted, head);
> > list_splice_tail_init(&vc->desc_issued, head);
--
Regards,
Laurent Pinchart
