media: nxp: imx8-isi: better handle the m2m usage_count

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: stable@vger.kernel.org
Suggested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Laurentiu Palcu <laurentiu.palcu@oss.nxp.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://lore.kernel.org/r/20241023085643.978729-1-laurentiu.palcu@oss.nxp.com
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

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 794050a6a919b8d108e4585d6be5ffd519e1311f..22e49d3a128732c077beb7ac2e2f688e0899f8e2 100644 (file)
--- 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;
 }