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media: v4l2-mem2mem: support held capture buffers

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Check for held buffers that are ready to be returned to vb2 in
__v4l2_m2m_try_queue(). This avoids drivers having to handle this
case.

Add v4l2_m2m_buf_done_and_job_finish() to correctly return source
and destination buffers and mark the job as finished while taking
a held destination buffer into account (i.e. that buffer won't be
returned). This has to be done while job_spinlock is held to avoid
race conditions.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
This commit is contained in:
Hans Verkuil 2019-10-11 06:32:41 -03:00 committed by Mauro Carvalho Chehab
parent 137272cdf7
commit f8cca8c97a
2 changed files with 128 additions and 35 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

130
drivers/media/v4l2-core/v4l2-mem2mem.c
View file

@ -284,7 +284,8 @@ static void v4l2_m2m_try_run(struct v4l2_m2m_dev *m2m_dev)
static void __v4l2_m2m_try_queue(struct v4l2_m2m_dev *m2m_dev,
struct v4l2_m2m_ctx *m2m_ctx)
{
unsigned long flags_job, flags_out, flags_cap;
unsigned long flags_job;
struct vb2_v4l2_buffer *dst, *src;
dprintk("Trying to schedule a job for m2m_ctx: %p\n", m2m_ctx);
@ -307,20 +308,30 @@ static void __v4l2_m2m_try_queue(struct v4l2_m2m_dev *m2m_dev,
goto job_unlock;
}
spin_lock_irqsave(&m2m_ctx->out_q_ctx.rdy_spinlock, flags_out);
if (list_empty(&m2m_ctx->out_q_ctx.rdy_queue)
&& !m2m_ctx->out_q_ctx.buffered) {
src = v4l2_m2m_next_src_buf(m2m_ctx);
dst = v4l2_m2m_next_dst_buf(m2m_ctx);
if (!src && !m2m_ctx->out_q_ctx.buffered) {
dprintk("No input buffers available\n");
goto out_unlock;
goto job_unlock;
}
spin_lock_irqsave(&m2m_ctx->cap_q_ctx.rdy_spinlock, flags_cap);
if (list_empty(&m2m_ctx->cap_q_ctx.rdy_queue)
&& !m2m_ctx->cap_q_ctx.buffered) {
if (!dst && !m2m_ctx->cap_q_ctx.buffered) {
dprintk("No output buffers available\n");
goto cap_unlock;
goto job_unlock;
}
if (src && dst &&
dst->is_held && dst->vb2_buf.copied_timestamp &&
dst->vb2_buf.timestamp != src->vb2_buf.timestamp) {
dst->is_held = false;
v4l2_m2m_dst_buf_remove(m2m_ctx);
v4l2_m2m_buf_done(dst, VB2_BUF_STATE_DONE);
dst = v4l2_m2m_next_dst_buf(m2m_ctx);
if (!dst && !m2m_ctx->cap_q_ctx.buffered) {
dprintk("No output buffers available after returning held buffer\n");
goto job_unlock;
}
}
spin_unlock_irqrestore(&m2m_ctx->cap_q_ctx.rdy_spinlock, flags_cap);
spin_unlock_irqrestore(&m2m_ctx->out_q_ctx.rdy_spinlock, flags_out);
if (m2m_dev->m2m_ops->job_ready
&& (!m2m_dev->m2m_ops->job_ready(m2m_ctx->priv))) {
@ -331,13 +342,6 @@ static void __v4l2_m2m_try_queue(struct v4l2_m2m_dev *m2m_dev,
list_add_tail(&m2m_ctx->queue, &m2m_dev->job_queue);
m2m_ctx->job_flags |= TRANS_QUEUED;
spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags_job);
return;
cap_unlock:
spin_unlock_irqrestore(&m2m_ctx->cap_q_ctx.rdy_spinlock, flags_cap);
out_unlock:
spin_unlock_irqrestore(&m2m_ctx->out_q_ctx.rdy_spinlock, flags_out);
job_unlock:
spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags_job);
}
@ -412,37 +416,97 @@ static void v4l2_m2m_cancel_job(struct v4l2_m2m_ctx *m2m_ctx)
}
}
void v4l2_m2m_job_finish(struct v4l2_m2m_dev *m2m_dev,
struct v4l2_m2m_ctx *m2m_ctx)
/*
* Schedule the next job, called from v4l2_m2m_job_finish() or
* v4l2_m2m_buf_done_and_job_finish().
*/
static void v4l2_m2m_schedule_next_job(struct v4l2_m2m_dev *m2m_dev,
struct v4l2_m2m_ctx *m2m_ctx)
{
unsigned long flags;
/*
* This instance might have more buffers ready, but since we do not
* allow more than one job on the job_queue per instance, each has
* to be scheduled separately after the previous one finishes.
*/
__v4l2_m2m_try_queue(m2m_dev, m2m_ctx);
spin_lock_irqsave(&m2m_dev->job_spinlock, flags);
/*
* We might be running in atomic context,
* but the job must be run in non-atomic context.
*/
schedule_work(&m2m_dev->job_work);
}
/*
* Assumes job_spinlock is held, called from v4l2_m2m_job_finish() or
* v4l2_m2m_buf_done_and_job_finish().
*/
static bool _v4l2_m2m_job_finish(struct v4l2_m2m_dev *m2m_dev,
struct v4l2_m2m_ctx *m2m_ctx)
{
if (!m2m_dev->curr_ctx || m2m_dev->curr_ctx != m2m_ctx) {
spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);
dprintk("Called by an instance not currently running\n");
return;
return false;
}
list_del(&m2m_dev->curr_ctx->queue);
m2m_dev->curr_ctx->job_flags &= ~(TRANS_QUEUED | TRANS_RUNNING);
wake_up(&m2m_dev->curr_ctx->finished);
m2m_dev->curr_ctx = NULL;
return true;
}
void v4l2_m2m_job_finish(struct v4l2_m2m_dev *m2m_dev,
struct v4l2_m2m_ctx *m2m_ctx)
{
unsigned long flags;
bool schedule_next;
/*
* This function should not be used for drivers that support
* holding capture buffers. Those should use
* v4l2_m2m_buf_done_and_job_finish() instead.
*/
WARN_ON(m2m_ctx->cap_q_ctx.q.subsystem_flags &
VB2_V4L2_FL_SUPPORTS_M2M_HOLD_CAPTURE_BUF);
spin_lock_irqsave(&m2m_dev->job_spinlock, flags);
schedule_next = _v4l2_m2m_job_finish(m2m_dev, m2m_ctx);
spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);
/* This instance might have more buffers ready, but since we do not
* allow more than one job on the job_queue per instance, each has
* to be scheduled separately after the previous one finishes. */
__v4l2_m2m_try_queue(m2m_dev, m2m_ctx);
/* We might be running in atomic context,
* but the job must be run in non-atomic context.
*/
schedule_work(&m2m_dev->job_work);
if (schedule_next)
v4l2_m2m_schedule_next_job(m2m_dev, m2m_ctx);
}
EXPORT_SYMBOL(v4l2_m2m_job_finish);
void v4l2_m2m_buf_done_and_job_finish(struct v4l2_m2m_dev *m2m_dev,
struct v4l2_m2m_ctx *m2m_ctx,
enum vb2_buffer_state state)
{
struct vb2_v4l2_buffer *src_buf, *dst_buf;
bool schedule_next = false;
unsigned long flags;
spin_lock_irqsave(&m2m_dev->job_spinlock, flags);
src_buf = v4l2_m2m_src_buf_remove(m2m_ctx);
dst_buf = v4l2_m2m_next_dst_buf(m2m_ctx);
if (WARN_ON(!src_buf || !dst_buf))
goto unlock;
v4l2_m2m_buf_done(src_buf, state);
dst_buf->is_held = src_buf->flags & V4L2_BUF_FLAG_M2M_HOLD_CAPTURE_BUF;
if (!dst_buf->is_held) {
v4l2_m2m_dst_buf_remove(m2m_ctx);
v4l2_m2m_buf_done(dst_buf, state);
}
schedule_next = _v4l2_m2m_job_finish(m2m_dev, m2m_ctx);
unlock:
spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);
if (schedule_next)
v4l2_m2m_schedule_next_job(m2m_dev, m2m_ctx);
}
EXPORT_SYMBOL(v4l2_m2m_buf_done_and_job_finish);
int v4l2_m2m_reqbufs(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
struct v4l2_requestbuffers *reqbufs)
{

33
include/media/v4l2-mem2mem.h
View file

@ -21,7 +21,8 @@
* callback.
* The job does NOT have to end before this callback returns
* (and it will be the usual case). When the job finishes,
* v4l2_m2m_job_finish() has to be called.
* v4l2_m2m_job_finish() or v4l2_m2m_buf_done_and_job_finish()
* has to be called.
* @job_ready: optional. Should return 0 if the driver does not have a job
* fully prepared to run yet (i.e. it will not be able to finish a
* transaction without sleeping). If not provided, it will be
@ -33,7 +34,8 @@
* stop the device safely; e.g. in the next interrupt handler),
* even if the transaction would not have been finished by then.
* After the driver performs the necessary steps, it has to call
* v4l2_m2m_job_finish() (as if the transaction ended normally).
* v4l2_m2m_job_finish() or v4l2_m2m_buf_done_and_job_finish() as
* if the transaction ended normally.
* This function does not have to (and will usually not) wait
* until the device enters a state when it can be stopped.
*/
@ -173,6 +175,33 @@ void v4l2_m2m_try_schedule(struct v4l2_m2m_ctx *m2m_ctx);
void v4l2_m2m_job_finish(struct v4l2_m2m_dev *m2m_dev,
struct v4l2_m2m_ctx *m2m_ctx);
/**
* v4l2_m2m_buf_done_and_job_finish() - return source/destination buffers with
* state and inform the framework that a job has been finished and have it
* clean up
*
* @m2m_dev: opaque pointer to the internal data to handle M2M context
* @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
* @state: vb2 buffer state passed to v4l2_m2m_buf_done().
*
* Drivers that set V4L2_BUF_CAP_SUPPORTS_M2M_HOLD_CAPTURE_BUF must use this
* function instead of job_finish() to take held buffers into account. It is
* optional for other drivers.
*
* This function removes the source buffer from the ready list and returns
* it with the given state. The same is done for the destination buffer, unless
* it is marked 'held'. In that case the buffer is kept on the ready list.
*
* After that the job is finished (see job_finish()).
*
* This allows for multiple output buffers to be used to fill in a single
* capture buffer. This is typically used by stateless decoders where
* multiple e.g. H.264 slices contribute to a single decoded frame.
*/
void v4l2_m2m_buf_done_and_job_finish(struct v4l2_m2m_dev *m2m_dev,
struct v4l2_m2m_ctx *m2m_ctx,
enum vb2_buffer_state state);
static inline void
v4l2_m2m_buf_done(struct vb2_v4l2_buffer *buf, enum vb2_buffer_state state)
{