[PATCH] media: mtk-jpeg: fix continuous log "Context is NULL"

On Tue, 2017-03-14 at 22:21 +0800, Minghsiu Tsai wrote:

The symptom is continuous log "mtk-jpeg 18004000.jpegdec: Context is NULL"
in kernel log. It is becauese the error handling in irq doesn't clear
interrupt.

The calling flow like as below when issue happen
mtk_jpeg_device_run()
mtk_jpeg_job_abort()
  v4l2_m2m_job_finish() -> m2m_dev->curr_ctx = NULL;
mtk_jpeg_dec_irq()
  v4l2_m2m_get_curr_priv()
     -> m2m_dev->curr_ctx == NULL
     -> return NULL
log "Context is NULL"

There is race condition between job_abort() and irq. In order to simplify
code, don't want to add extra flag to maintain state, empty job_abort() and
clear interrupt before v4l2_m2m_get_curr_priv() in irq.

Signed-off-by: Minghsiu Tsai <minghsiu.tsai@mediatek.com>
---
 drivers/media/platform/mtk-jpeg/mtk_jpeg_core.c | 14 ++------------
 1 file changed, 2 insertions(+), 12 deletions(-)

Acked-by: Rick Chang <redacted>