[media.git/next] media: nxp: imx8-isi: better handle the m2m usage_count

[media-ci]

On Wed Oct 23 11:56:43 2024 +0300, Laurentiu Palcu wrote:
> Currently, if streamon/streamoff calls are imbalanced we can either end up
> with a negative ISI m2m usage_count (if streamoff() is called more times
> than streamon()) in which case we'll not be able to restart the ISI pipe
> next time, or the usage_count never gets to 0 and the pipe is never
> switched off.
> 
> To avoid that, add a 'streaming' flag to mxc_isi_m2m_ctx_queue_data and use it
> in the streamon/streamoff to avoid incrementing/decrementing the usage_count
> uselessly, if called multiple times from the same context.
> 
> Fixes: cf21f328fcafac ("media: nxp: Add i.MX8 ISI driver")
> Cc: sta...@vger.kernel.org
> Suggested-by: Laurent Pinchart <laurent.pinch...@ideasonboard.com>
> Signed-off-by: Laurentiu Palcu <laurentiu.pa...@oss.nxp.com>
> Reviewed-by: Laurent Pinchart <laurent.pinch...@ideasonboard.com>
> Link: 
> https://lore.kernel.org/r/20241023085643.978729-1-laurentiu.pa...@oss.nxp.com
> Signed-off-by: Laurent Pinchart <laurent.pinch...@ideasonboard.com>
> Signed-off-by: Mauro Carvalho Chehab <mchehab+hua...@kernel.org>

Patch committed.

Thanks,
Mauro Carvalho Chehab

 drivers/media/platform/nxp/imx8-isi/imx8-isi-m2m.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

---

diff --git a/drivers/media/platform/nxp/imx8-isi/imx8-isi-m2m.c 
b/drivers/media/platform/nxp/imx8-isi/imx8-isi-m2m.c
index 794050a6a919..22e49d3a1287 100644
--- a/drivers/media/platform/nxp/imx8-isi/imx8-isi-m2m.c
+++ b/drivers/media/platform/nxp/imx8-isi/imx8-isi-m2m.c
@@ -43,6 +43,7 @@ struct mxc_isi_m2m_ctx_queue_data {
        struct v4l2_pix_format_mplane format;
        const struct mxc_isi_format_info *info;
        u32 sequence;
+       bool streaming;
 };
 
 struct mxc_isi_m2m_ctx {
@@ -484,15 +485,18 @@ static int mxc_isi_m2m_streamon(struct file *file, void 
*fh,
                                enum v4l2_buf_type type)
 {
        struct mxc_isi_m2m_ctx *ctx = to_isi_m2m_ctx(fh);
+       struct mxc_isi_m2m_ctx_queue_data *q = mxc_isi_m2m_ctx_qdata(ctx, type);
        const struct v4l2_pix_format_mplane *out_pix = &ctx->queues.out.format;
        const struct v4l2_pix_format_mplane *cap_pix = &ctx->queues.cap.format;
        const struct mxc_isi_format_info *cap_info = ctx->queues.cap.info;
        const struct mxc_isi_format_info *out_info = ctx->queues.out.info;
        struct mxc_isi_m2m *m2m = ctx->m2m;
        bool bypass;
-
        int ret;
 
+       if (q->streaming)
+               return 0;
+
        mutex_lock(&m2m->lock);
 
        if (m2m->usage_count == INT_MAX) {
@@ -545,6 +549,8 @@ static int mxc_isi_m2m_streamon(struct file *file, void *fh,
                goto unchain;
        }
 
+       q->streaming = true;
+
        return 0;
 
 unchain:
@@ -567,10 +573,14 @@ static int mxc_isi_m2m_streamoff(struct file *file, void 
*fh,
                                 enum v4l2_buf_type type)
 {
        struct mxc_isi_m2m_ctx *ctx = to_isi_m2m_ctx(fh);
+       struct mxc_isi_m2m_ctx_queue_data *q = mxc_isi_m2m_ctx_qdata(ctx, type);
        struct mxc_isi_m2m *m2m = ctx->m2m;
 
        v4l2_m2m_ioctl_streamoff(file, fh, type);
 
+       if (!q->streaming)
+               return 0;
+
        mutex_lock(&m2m->lock);
 
        /*
@@ -596,6 +606,8 @@ static int mxc_isi_m2m_streamoff(struct file *file, void 
*fh,
 
        mutex_unlock(&m2m->lock);
 
+       q->streaming = false;
+
        return 0;
 }