| Message ID | 20240927080420.3867806-1-laurentiu.palcu@oss.nxp.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v2] media: nxp: imx8-isi: better handle the m2m usage_count | expand |
On Fri, Sep 27, 2024 at 11:04:20AM +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. > > So, to avoid that, add an 'in_use' flag in the ctx structure that will > keep track whether the output/capture queues have been started or not, > and use it to avoid decrementing/incrementing the usage_count > unnecessarily. > > Fixes: cf21f328fcafac ("media: nxp: Add i.MX8 ISI driver") > Signed-off-by: Laurentiu Palcu <laurentiu.palcu@oss.nxp.com> > --- > v2: > * Changed the way 'usage_count' is incremented/decremented by taking > into account the context the streamon/streamoff functions are called > from; > * Changed the commit message and subject to reflect the changes; > > .../platform/nxp/imx8-isi/imx8-isi-m2m.c | 24 +++++++++++++++---- > 1 file changed, 20 insertions(+), 4 deletions(-) > > 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 9745d6219a166..3f06ae1349e53 100644 > --- a/drivers/media/platform/nxp/imx8-isi/imx8-isi-m2m.c > +++ b/drivers/media/platform/nxp/imx8-isi/imx8-isi-m2m.c > @@ -65,6 +65,7 @@ struct mxc_isi_m2m_ctx { > } ctrls; > > bool chained; > + bool in_use[2]; I think you can store this in mxc_isi_m2m_ctx_queue_data instead as a bool streaming; > }; > > static inline struct mxc_isi_m2m_buffer * > @@ -491,6 +492,7 @@ static int mxc_isi_m2m_streamon(struct file *file, void *fh, > 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 already_in_use; > bool bypass; > > int ret; > @@ -502,6 +504,8 @@ static int mxc_isi_m2m_streamon(struct file *file, void *fh, > goto unlock; > } > > + already_in_use = ctx->in_use[type == V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE]; > + As the streamon and streamoff operation are covered by the same queue lock for all contexts, you can do all this outside of the m2m->lock sections. I think the following patch (untested) should do and would be simpler: 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 9745d6219a16..cd6c52e9d158 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 { @@ -486,15 +487,18 @@ 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) { @@ -547,6 +551,8 @@ static int mxc_isi_m2m_streamon(struct file *file, void *fh, goto unchain; } + q->streaming = true; + return 0; unchain: @@ -569,10 +575,14 @@ 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); /* @@ -598,6 +608,8 @@ static int mxc_isi_m2m_streamoff(struct file *file, void *fh, mutex_unlock(&m2m->lock); + q->streaming = false; + return 0; } If this works for you, could you turn it into a v3 ? > bypass = cap_pix->width == out_pix->width && > cap_pix->height == out_pix->height && > cap_info->encoding == out_info->encoding; > @@ -520,7 +524,10 @@ static int mxc_isi_m2m_streamon(struct file *file, void *fh, > mxc_isi_channel_get(m2m->pipe); > } > > - m2m->usage_count++; > + if (!already_in_use) { > + m2m->usage_count++; > + ctx->in_use[type == V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE] = true; > + } > > /* > * Allocate resources for the channel, counting how many users require > @@ -555,7 +562,12 @@ static int mxc_isi_m2m_streamon(struct file *file, void *fh, > ctx->chained = false; > > deinit: > - if (--m2m->usage_count == 0) { > + if (!already_in_use) { > + m2m->usage_count--; > + ctx->in_use[type == V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE] = false; > + } > + > + if (m2m->usage_count == 0) { > mxc_isi_channel_put(m2m->pipe); > mxc_isi_channel_release(m2m->pipe); > } > @@ -575,6 +587,9 @@ static int mxc_isi_m2m_streamoff(struct file *file, void *fh, > > mutex_lock(&m2m->lock); > > + if (!ctx->in_use[type == V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE]) > + goto unlock; > + > /* > * If the last context is this one, reset it to make sure the device > * will be reconfigured when streaming is restarted. > @@ -587,6 +602,8 @@ static int mxc_isi_m2m_streamoff(struct file *file, void *fh, > mxc_isi_channel_unchain(m2m->pipe); > ctx->chained = false; > > + ctx->in_use[type == V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE] = false; > + > /* Turn off the light with the last user. */ > if (--m2m->usage_count == 0) { > mxc_isi_channel_disable(m2m->pipe); > @@ -594,8 +611,7 @@ static int mxc_isi_m2m_streamoff(struct file *file, void *fh, > mxc_isi_channel_release(m2m->pipe); > } > > - WARN_ON(m2m->usage_count < 0); > - > +unlock: > mutex_unlock(&m2m->lock); > > return 0;
Hi Laurent, On Tue, Oct 22, 2024 at 02:05:19AM +0300, Laurent Pinchart wrote: > On Fri, Sep 27, 2024 at 11:04:20AM +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. > > > > So, to avoid that, add an 'in_use' flag in the ctx structure that will > > keep track whether the output/capture queues have been started or not, > > and use it to avoid decrementing/incrementing the usage_count > > unnecessarily. > > > > Fixes: cf21f328fcafac ("media: nxp: Add i.MX8 ISI driver") > > Signed-off-by: Laurentiu Palcu <laurentiu.palcu@oss.nxp.com> > > --- > > v2: > > * Changed the way 'usage_count' is incremented/decremented by taking > > into account the context the streamon/streamoff functions are called > > from; > > * Changed the commit message and subject to reflect the changes; > > > > .../platform/nxp/imx8-isi/imx8-isi-m2m.c | 24 +++++++++++++++---- > > 1 file changed, 20 insertions(+), 4 deletions(-) > > > > 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 9745d6219a166..3f06ae1349e53 100644 > > --- a/drivers/media/platform/nxp/imx8-isi/imx8-isi-m2m.c > > +++ b/drivers/media/platform/nxp/imx8-isi/imx8-isi-m2m.c > > @@ -65,6 +65,7 @@ struct mxc_isi_m2m_ctx { > > } ctrls; > > > > bool chained; > > + bool in_use[2]; > > I think you can store this in mxc_isi_m2m_ctx_queue_data instead as a > > bool streaming; > > > }; > > > > static inline struct mxc_isi_m2m_buffer * > > @@ -491,6 +492,7 @@ static int mxc_isi_m2m_streamon(struct file *file, void *fh, > > 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 already_in_use; > > bool bypass; > > > > int ret; > > @@ -502,6 +504,8 @@ static int mxc_isi_m2m_streamon(struct file *file, void *fh, > > goto unlock; > > } > > > > + already_in_use = ctx->in_use[type == V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE]; > > + > > As the streamon and streamoff operation are covered by the same queue > lock for all contexts, you can do all this outside of the m2m->lock > sections. I think the following patch (untested) should do and would be > simpler: > > 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 9745d6219a16..cd6c52e9d158 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 { > @@ -486,15 +487,18 @@ 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) { > @@ -547,6 +551,8 @@ static int mxc_isi_m2m_streamon(struct file *file, void *fh, > goto unchain; > } > > + q->streaming = true; > + > return 0; > > unchain: > @@ -569,10 +575,14 @@ 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); > > /* > @@ -598,6 +608,8 @@ static int mxc_isi_m2m_streamoff(struct file *file, void *fh, > > mutex_unlock(&m2m->lock); > > + q->streaming = false; > + > return 0; > } > > If this works for you, could you turn it into a v3 ? > It's funny that in my first tries to fix this I added a 'streaming' flag to mxc_isi_m2m_ctx_queue_data too. But I must've messed up something else as I dropped it and chose the other, more complicated, solution. :/ Anyway, I gave your patch a test and it seems to work fine so far. I'll send a v3 with your suggestion. Thanks, Laurentiu > > bypass = cap_pix->width == out_pix->width && > > cap_pix->height == out_pix->height && > > cap_info->encoding == out_info->encoding; > > @@ -520,7 +524,10 @@ static int mxc_isi_m2m_streamon(struct file *file, void *fh, > > mxc_isi_channel_get(m2m->pipe); > > } > > > > - m2m->usage_count++; > > + if (!already_in_use) { > > + m2m->usage_count++; > > + ctx->in_use[type == V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE] = true; > > + } > > > > /* > > * Allocate resources for the channel, counting how many users require > > @@ -555,7 +562,12 @@ static int mxc_isi_m2m_streamon(struct file *file, void *fh, > > ctx->chained = false; > > > > deinit: > > - if (--m2m->usage_count == 0) { > > + if (!already_in_use) { > > + m2m->usage_count--; > > + ctx->in_use[type == V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE] = false; > > + } > > + > > + if (m2m->usage_count == 0) { > > mxc_isi_channel_put(m2m->pipe); > > mxc_isi_channel_release(m2m->pipe); > > } > > @@ -575,6 +587,9 @@ static int mxc_isi_m2m_streamoff(struct file *file, void *fh, > > > > mutex_lock(&m2m->lock); > > > > + if (!ctx->in_use[type == V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE]) > > + goto unlock; > > + > > /* > > * If the last context is this one, reset it to make sure the device > > * will be reconfigured when streaming is restarted. > > @@ -587,6 +602,8 @@ static int mxc_isi_m2m_streamoff(struct file *file, void *fh, > > mxc_isi_channel_unchain(m2m->pipe); > > ctx->chained = false; > > > > + ctx->in_use[type == V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE] = false; > > + > > /* Turn off the light with the last user. */ > > if (--m2m->usage_count == 0) { > > mxc_isi_channel_disable(m2m->pipe); > > @@ -594,8 +611,7 @@ static int mxc_isi_m2m_streamoff(struct file *file, void *fh, > > mxc_isi_channel_release(m2m->pipe); > > } > > > > - WARN_ON(m2m->usage_count < 0); > > - > > +unlock: > > mutex_unlock(&m2m->lock); > > > > return 0; > > -- > Regards, > > Laurent Pinchart
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 9745d6219a166..3f06ae1349e53 100644 --- a/drivers/media/platform/nxp/imx8-isi/imx8-isi-m2m.c +++ b/drivers/media/platform/nxp/imx8-isi/imx8-isi-m2m.c @@ -65,6 +65,7 @@ struct mxc_isi_m2m_ctx { } ctrls; bool chained; + bool in_use[2]; }; static inline struct mxc_isi_m2m_buffer * @@ -491,6 +492,7 @@ static int mxc_isi_m2m_streamon(struct file *file, void *fh, 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 already_in_use; bool bypass; int ret; @@ -502,6 +504,8 @@ static int mxc_isi_m2m_streamon(struct file *file, void *fh, goto unlock; } + already_in_use = ctx->in_use[type == V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE]; + bypass = cap_pix->width == out_pix->width && cap_pix->height == out_pix->height && cap_info->encoding == out_info->encoding; @@ -520,7 +524,10 @@ static int mxc_isi_m2m_streamon(struct file *file, void *fh, mxc_isi_channel_get(m2m->pipe); } - m2m->usage_count++; + if (!already_in_use) { + m2m->usage_count++; + ctx->in_use[type == V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE] = true; + } /* * Allocate resources for the channel, counting how many users require @@ -555,7 +562,12 @@ static int mxc_isi_m2m_streamon(struct file *file, void *fh, ctx->chained = false; deinit: - if (--m2m->usage_count == 0) { + if (!already_in_use) { + m2m->usage_count--; + ctx->in_use[type == V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE] = false; + } + + if (m2m->usage_count == 0) { mxc_isi_channel_put(m2m->pipe); mxc_isi_channel_release(m2m->pipe); } @@ -575,6 +587,9 @@ static int mxc_isi_m2m_streamoff(struct file *file, void *fh, mutex_lock(&m2m->lock); + if (!ctx->in_use[type == V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE]) + goto unlock; + /* * If the last context is this one, reset it to make sure the device * will be reconfigured when streaming is restarted. @@ -587,6 +602,8 @@ static int mxc_isi_m2m_streamoff(struct file *file, void *fh, mxc_isi_channel_unchain(m2m->pipe); ctx->chained = false; + ctx->in_use[type == V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE] = false; + /* Turn off the light with the last user. */ if (--m2m->usage_count == 0) { mxc_isi_channel_disable(m2m->pipe); @@ -594,8 +611,7 @@ static int mxc_isi_m2m_streamoff(struct file *file, void *fh, mxc_isi_channel_release(m2m->pipe); } - WARN_ON(m2m->usage_count < 0); - +unlock: mutex_unlock(&m2m->lock); return 0;
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. So, to avoid that, add an 'in_use' flag in the ctx structure that will keep track whether the output/capture queues have been started or not, and use it to avoid decrementing/incrementing the usage_count unnecessarily. Fixes: cf21f328fcafac ("media: nxp: Add i.MX8 ISI driver") Signed-off-by: Laurentiu Palcu <laurentiu.palcu@oss.nxp.com> --- v2: * Changed the way 'usage_count' is incremented/decremented by taking into account the context the streamon/streamoff functions are called from; * Changed the commit message and subject to reflect the changes; .../platform/nxp/imx8-isi/imx8-isi-m2m.c | 24 +++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-)