Hi Dafna,
Thank you for the patch.
On Tue, May 12, 2020 at 02:05:21PM +0200, Dafna Hirschfeld wrote:
> This patch removes two locks in the rkisp1_stats struct:
> - The mutex 'wq_lock' that is used to protect the buffers list 'stat'
> - The spin_lock 'irq_lock' that is used to protect the
> variable 'is_streaming'
>
> It replaces them with one spin_lock 'stats_lock' that protects
> both the buffers list and the 'is_streaming' variable.
You should explain in the commit message why this is needed.
> Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@xxxxxxxxxxxxx>
> ---
> drivers/staging/media/rkisp1/rkisp1-common.h | 5 ++--
> drivers/staging/media/rkisp1/rkisp1-stats.c | 27 ++++++++++----------
> 2 files changed, 15 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/staging/media/rkisp1/rkisp1-common.h b/drivers/staging/media/rkisp1/rkisp1-common.h
> index c0ab16c6b3db..c635bb0a7727 100644
> --- a/drivers/staging/media/rkisp1/rkisp1-common.h
> +++ b/drivers/staging/media/rkisp1/rkisp1-common.h
> @@ -178,7 +178,7 @@ struct rkisp1_capture {
> /*
> * struct rkisp1_stats - ISP Statistics device
> *
> - * @irq_lock: buffer queue lock
> + * @stats_lock: locks the buffer list 'stat' and 'is_streaming'
> * @stat: stats buffer list
> * @readout_wq: workqueue for statistics information read
> */
> @@ -186,13 +186,12 @@ struct rkisp1_stats {
> struct rkisp1_vdev_node vnode;
> struct rkisp1_device *rkisp1;
>
> - spinlock_t irq_lock;
> + spinlock_t stats_lock; /* locks 'is_streaming', and 'stats' */
If there's a single lock, how about simply calling it 'lock' ?
> struct list_head stat;
> struct v4l2_format vdev_fmt;
> bool is_streaming;
>
> struct workqueue_struct *readout_wq;
> - struct mutex wq_lock;
> };
>
> /*
> diff --git a/drivers/staging/media/rkisp1/rkisp1-stats.c b/drivers/staging/media/rkisp1/rkisp1-stats.c
> index 5578fdeb8a18..e6fb2c5f3b3e 100644
> --- a/drivers/staging/media/rkisp1/rkisp1-stats.c
> +++ b/drivers/staging/media/rkisp1/rkisp1-stats.c
> @@ -130,12 +130,13 @@ static void rkisp1_stats_vb2_buf_queue(struct vb2_buffer *vb)
> container_of(vbuf, struct rkisp1_buffer, vb);
> struct vb2_queue *vq = vb->vb2_queue;
> struct rkisp1_stats *stats_dev = vq->drv_priv;
> + unsigned long flags;
>
> stats_buf->vaddr[0] = vb2_plane_vaddr(vb, 0);
>
> - mutex_lock(&stats_dev->wq_lock);
> + spin_lock_irqsave(&stats_dev->stats_lock, flags);
As I explained in a previous e-mail in this series, you could use
spin_lock_irq() here as there's a guarantee interrupts are not disabled.
Up to you.
> list_add_tail(&stats_buf->queue, &stats_dev->stat);
> - mutex_unlock(&stats_dev->wq_lock);
> + spin_unlock_irqrestore(&stats_dev->stats_lock, flags);
> }
>
> static int rkisp1_stats_vb2_buf_prepare(struct vb2_buffer *vb)
> @@ -156,13 +157,13 @@ static void rkisp1_stats_vb2_stop_streaming(struct vb2_queue *vq)
> unsigned int i;
>
> /* Make sure no new work queued in isr before draining wq */
> - spin_lock_irqsave(&stats->irq_lock, flags);
> + spin_lock_irqsave(&stats->stats_lock, flags);
> stats->is_streaming = false;
> - spin_unlock_irqrestore(&stats->irq_lock, flags);
> + spin_unlock_irqrestore(&stats->stats_lock, flags);
>
> drain_workqueue(stats->readout_wq);
>
> - mutex_lock(&stats->wq_lock);
> + spin_lock_irqsave(&stats->stats_lock, flags);
> for (i = 0; i < RKISP1_ISP_STATS_REQ_BUFS_MAX; i++) {
> if (list_empty(&stats->stat))
> break;
> @@ -171,7 +172,7 @@ static void rkisp1_stats_vb2_stop_streaming(struct vb2_queue *vq)
> list_del(&buf->queue);
> vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_ERROR);
> }
> - mutex_unlock(&stats->wq_lock);
> + spin_unlock_irqrestore(&stats->stats_lock, flags);
> }
>
> static int
> @@ -333,6 +334,7 @@ rkisp1_stats_send_measurement(struct rkisp1_stats *stats,
> unsigned int frame_sequence =
> atomic_read(&stats->rkisp1->isp.frame_sequence);
> u64 timestamp = ktime_get_ns();
> + unsigned long flags;
>
> if (frame_sequence != meas_work->frame_id) {
> dev_warn(stats->rkisp1->dev,
> @@ -341,14 +343,14 @@ rkisp1_stats_send_measurement(struct rkisp1_stats *stats,
> frame_sequence = meas_work->frame_id;
> }
>
> - mutex_lock(&stats->wq_lock);
> + spin_lock_irqsave(&stats->stats_lock, flags);
> /* get one empty buffer */
> if (!list_empty(&stats->stat)) {
> cur_buf = list_first_entry(&stats->stat,
> struct rkisp1_buffer, queue);
> list_del(&cur_buf->queue);
> }
> - mutex_unlock(&stats->wq_lock);
> + spin_unlock_irqrestore(&stats->stats_lock, flags);
>
> if (!cur_buf)
> return;
> @@ -406,7 +408,7 @@ void rkisp1_stats_isr(struct rkisp1_stats *stats, u32 isp_ris)
> unsigned long flags;
> u32 val;
>
> - spin_lock_irqsave(&stats->irq_lock, flags);
> + spin_lock_irqsave(&stats->stats_lock, flags);
>
> val = RKISP1_STATS_MEAS_MASK;
> rkisp1_write(rkisp1, val, RKISP1_CIF_ISP_ICR);
> @@ -436,7 +438,7 @@ void rkisp1_stats_isr(struct rkisp1_stats *stats, u32 isp_ris)
> }
>
> unlock:
> - spin_unlock_irqrestore(&stats->irq_lock, flags);
> + spin_unlock_irqrestore(&stats->stats_lock, flags);
> }
>
> static void rkisp1_init_stats(struct rkisp1_stats *stats)
> @@ -456,10 +458,9 @@ int rkisp1_stats_register(struct rkisp1_stats *stats,
> int ret;
>
> stats->rkisp1 = rkisp1;
> - mutex_init(&stats->wq_lock);
> mutex_init(&node->vlock);
> INIT_LIST_HEAD(&stats->stat);
> - spin_lock_init(&stats->irq_lock);
> + spin_lock_init(&stats->stats_lock);
>
> strscpy(vdev->name, RKISP1_STATS_DEV_NAME, sizeof(vdev->name));
>
> @@ -506,7 +507,6 @@ int rkisp1_stats_register(struct rkisp1_stats *stats,
> err_release_queue:
> vb2_queue_release(vdev->queue);
> mutex_destroy(&node->vlock);
> - mutex_destroy(&stats->wq_lock);
> return ret;
> }
>
> @@ -520,5 +520,4 @@ void rkisp1_stats_unregister(struct rkisp1_stats *stats)
> media_entity_cleanup(&vdev->entity);
> vb2_queue_release(vdev->queue);
> mutex_destroy(&node->vlock);
> - mutex_destroy(&stats->wq_lock);
> }
--
Regards,
Laurent Pinchart
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