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Message-ID: <a4053c39-3781-4fc4-9c5e-45f32b5525ed@ideasonboard.com>
Date: Wed, 27 Mar 2024 14:29:02 +0200
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Subject: Re: [PATCH 3/3] dma: Add lockdep asserts to virt-dma
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To: Sean Anderson <sean.anderson@linux.dev>
Cc: Michal Simek <michal.simek@amd.com>, linux-kernel@vger.kernel.org,
 linux-arm-kernel@lists.infradead.org,
 Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
 dmaengine@vger.kernel.org, Vinod Koul <vkoul@kernel.org>
References: <20240308210034.3634938-1-sean.anderson@linux.dev>
 <20240308210034.3634938-4-sean.anderson@linux.dev>
From: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
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In-Reply-To: <20240308210034.3634938-4-sean.anderson@linux.dev>
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On 08/03/2024 23:00, Sean Anderson wrote:
> Add lockdep asserts to all functions with "vc.lock must be held by
> caller" in their documentation. This will help catch cases where these
> assumptions do not hold.
> 
> Signed-off-by: Sean Anderson <sean.anderson@linux.dev>
> ---

Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>

  Tomi

>   drivers/dma/virt-dma.h | 10 ++++++++++
>   1 file changed, 10 insertions(+)
> 
> 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);