diff options
author | Ezequiel Garcia <ezequiel@collabora.com> | 2018-07-25 13:15:12 -0400 |
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committer | Mauro Carvalho Chehab <mchehab+samsung@kernel.org> | 2018-07-27 12:59:13 -0400 |
commit | 9db3bbf58be59ab496ccd1c7528f4b0e8835c5b1 (patch) | |
tree | 8bb35f66cf211c928f9668e127eab11f54348b1f | |
parent | 39dd23dc9d4c512954ec511d22d93ea854cf0265 (diff) | |
download | linux-9db3bbf58be59ab496ccd1c7528f4b0e8835c5b1.tar.bz2 |
media: v4l2-mem2mem: Fix missing v4l2_m2m_try_run call
Commit 34dbb848d5e4 ("media: mem2mem: Remove excessive try_run call")
removed a redundant call to v4l2_m2m_try_run but instead introduced
a bug. Consider the following case:
1) Context A schedules, queues and runs job A.
2) While the m2m device is running, context B schedules
and queues job B. Job B cannot run, because it has to
wait for job A.
3) Job A completes, calls v4l2_m2m_job_finish, and tries
to queue a job for context A, but since the context is
empty it won't do anything.
In this scenario, queued job B will never run. Fix this by calling
v4l2_m2m_try_run from v4l2_m2m_try_schedule.
While here, add more documentation to these functions.
Fixes: 34dbb848d5e4 ("media: mem2mem: Remove excessive try_run call")
Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
[hans.verkuil@cisco.com: split >80 cols line]
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
-rw-r--r-- | drivers/media/v4l2-core/v4l2-mem2mem.c | 33 |
1 files changed, 30 insertions, 3 deletions
diff --git a/drivers/media/v4l2-core/v4l2-mem2mem.c b/drivers/media/v4l2-core/v4l2-mem2mem.c index d9565ee44578..0a93c5b173c2 100644 --- a/drivers/media/v4l2-core/v4l2-mem2mem.c +++ b/drivers/media/v4l2-core/v4l2-mem2mem.c @@ -249,15 +249,24 @@ static void v4l2_m2m_try_run(struct v4l2_m2m_dev *m2m_dev) m2m_dev->curr_ctx->job_flags |= TRANS_RUNNING; spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags); + dprintk("Running job on m2m_ctx: %p\n", m2m_dev->curr_ctx); m2m_dev->m2m_ops->device_run(m2m_dev->curr_ctx->priv); } -void v4l2_m2m_try_schedule(struct v4l2_m2m_ctx *m2m_ctx) +/* + * __v4l2_m2m_try_queue() - queue a job + * @m2m_dev: m2m device + * @m2m_ctx: m2m context + * + * Check if this context is ready to queue a job. + * + * This function can run in interrupt context. + */ +static void __v4l2_m2m_try_queue(struct v4l2_m2m_dev *m2m_dev, + struct v4l2_m2m_ctx *m2m_ctx) { - struct v4l2_m2m_dev *m2m_dev; unsigned long flags_job, flags_out, flags_cap; - m2m_dev = m2m_ctx->m2m_dev; dprintk("Trying to schedule a job for m2m_ctx: %p\n", m2m_ctx); if (!m2m_ctx->out_q_ctx.q.streaming @@ -315,7 +324,25 @@ void v4l2_m2m_try_schedule(struct v4l2_m2m_ctx *m2m_ctx) m2m_ctx->job_flags |= TRANS_QUEUED; spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags_job); +} + +/** + * v4l2_m2m_try_schedule() - schedule and possibly run a job for any context + * @m2m_ctx: m2m context + * + * Check if this context is ready to queue a job. If suitable, + * run the next queued job on the mem2mem device. + * + * This function shouldn't run in interrupt context. + * + * Note that v4l2_m2m_try_schedule() can schedule one job for this context, + * and then run another job for another context. + */ +void v4l2_m2m_try_schedule(struct v4l2_m2m_ctx *m2m_ctx) +{ + struct v4l2_m2m_dev *m2m_dev = m2m_ctx->m2m_dev; + __v4l2_m2m_try_queue(m2m_dev, m2m_ctx); v4l2_m2m_try_run(m2m_dev); } EXPORT_SYMBOL_GPL(v4l2_m2m_try_schedule); |