From 28100165c3f27f681fee8b60e4e44f64a739c454 Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Mon, 16 Feb 2009 15:27:44 -0300 Subject: [PATCH] V4L/DVB (10572): Revert commit dda06a8e4610757def753ee3a541a0b1a1feb36b On Mon, 02 Feb 2009, Hartmut wrote: This change set is wrong. The affected functions cannot be called from an interrupt context, because they may process large buffers. In this case, interrupts are disabled for a long time. Functions, like dvb_dmx_swfilter_packets(), could be called only from a tasklet. This change set does hide some strong design bugs in dm1105.c and au0828-dvb.c. Please revert this change set and do fix the bugs in dm1105.c and au0828-dvb.c (and other files). On Sun, 15 Feb 2009, Oliver Endriss wrote: This changeset _must_ be reverted! It breaks all kernels since 2.6.27 for applications which use DVB and require a low interrupt latency. It is a very bad idea to call the demuxer to process data buffers with interrupts disabled! On Mon, 16 Feb 2009, Trent Piepho wrote: I agree, this is bad. The demuxer is far too much work to be done with IRQs off. IMHO, even doing it under a spin-lock is excessive. It should be a mutex. Drivers should use a work-queue to feed the demuxer. Thank you for testing this changeset and discovering the issues on it. Cc: Trent Piepho Cc: Hartmut Cc: Oliver Endriss Cc: Andreas Oberritter Signed-off-by: Mauro Carvalho Chehab --- drivers/media/dvb/dvb-core/dmxdev.c | 16 +++++++--------- drivers/media/dvb/dvb-core/dvb_demux.c | 16 ++++++---------- 2 files changed, 13 insertions(+), 19 deletions(-) diff --git a/drivers/media/dvb/dvb-core/dmxdev.c b/drivers/media/dvb/dvb-core/dmxdev.c index 0c733c66a44..069d847ba88 100644 --- a/drivers/media/dvb/dvb-core/dmxdev.c +++ b/drivers/media/dvb/dvb-core/dmxdev.c @@ -364,16 +364,15 @@ static int dvb_dmxdev_section_callback(const u8 *buffer1, size_t buffer1_len, enum dmx_success success) { struct dmxdev_filter *dmxdevfilter = filter->priv; - unsigned long flags; int ret; if (dmxdevfilter->buffer.error) { wake_up(&dmxdevfilter->buffer.queue); return 0; } - spin_lock_irqsave(&dmxdevfilter->dev->lock, flags); + spin_lock(&dmxdevfilter->dev->lock); if (dmxdevfilter->state != DMXDEV_STATE_GO) { - spin_unlock_irqrestore(&dmxdevfilter->dev->lock, flags); + spin_unlock(&dmxdevfilter->dev->lock); return 0; } del_timer(&dmxdevfilter->timer); @@ -392,7 +391,7 @@ static int dvb_dmxdev_section_callback(const u8 *buffer1, size_t buffer1_len, } if (dmxdevfilter->params.sec.flags & DMX_ONESHOT) dmxdevfilter->state = DMXDEV_STATE_DONE; - spin_unlock_irqrestore(&dmxdevfilter->dev->lock, flags); + spin_unlock(&dmxdevfilter->dev->lock); wake_up(&dmxdevfilter->buffer.queue); return 0; } @@ -404,12 +403,11 @@ static int dvb_dmxdev_ts_callback(const u8 *buffer1, size_t buffer1_len, { struct dmxdev_filter *dmxdevfilter = feed->priv; struct dvb_ringbuffer *buffer; - unsigned long flags; int ret; - spin_lock_irqsave(&dmxdevfilter->dev->lock, flags); + spin_lock(&dmxdevfilter->dev->lock); if (dmxdevfilter->params.pes.output == DMX_OUT_DECODER) { - spin_unlock_irqrestore(&dmxdevfilter->dev->lock, flags); + spin_unlock(&dmxdevfilter->dev->lock); return 0; } @@ -419,7 +417,7 @@ static int dvb_dmxdev_ts_callback(const u8 *buffer1, size_t buffer1_len, else buffer = &dmxdevfilter->dev->dvr_buffer; if (buffer->error) { - spin_unlock_irqrestore(&dmxdevfilter->dev->lock, flags); + spin_unlock(&dmxdevfilter->dev->lock); wake_up(&buffer->queue); return 0; } @@ -430,7 +428,7 @@ static int dvb_dmxdev_ts_callback(const u8 *buffer1, size_t buffer1_len, dvb_ringbuffer_flush(buffer); buffer->error = ret; } - spin_unlock_irqrestore(&dmxdevfilter->dev->lock, flags); + spin_unlock(&dmxdevfilter->dev->lock); wake_up(&buffer->queue); return 0; } diff --git a/drivers/media/dvb/dvb-core/dvb_demux.c b/drivers/media/dvb/dvb-core/dvb_demux.c index a2c1fd5d2f6..e2eca0b1fe7 100644 --- a/drivers/media/dvb/dvb-core/dvb_demux.c +++ b/drivers/media/dvb/dvb-core/dvb_demux.c @@ -399,9 +399,7 @@ static void dvb_dmx_swfilter_packet(struct dvb_demux *demux, const u8 *buf) void dvb_dmx_swfilter_packets(struct dvb_demux *demux, const u8 *buf, size_t count) { - unsigned long flags; - - spin_lock_irqsave(&demux->lock, flags); + spin_lock(&demux->lock); while (count--) { if (buf[0] == 0x47) @@ -409,17 +407,16 @@ void dvb_dmx_swfilter_packets(struct dvb_demux *demux, const u8 *buf, buf += 188; } - spin_unlock_irqrestore(&demux->lock, flags); + spin_unlock(&demux->lock); } EXPORT_SYMBOL(dvb_dmx_swfilter_packets); void dvb_dmx_swfilter(struct dvb_demux *demux, const u8 *buf, size_t count) { - unsigned long flags; int p = 0, i, j; - spin_lock_irqsave(&demux->lock, flags); + spin_lock(&demux->lock); if (demux->tsbufp) { i = demux->tsbufp; @@ -452,18 +449,17 @@ void dvb_dmx_swfilter(struct dvb_demux *demux, const u8 *buf, size_t count) } bailout: - spin_unlock_irqrestore(&demux->lock, flags); + spin_unlock(&demux->lock); } EXPORT_SYMBOL(dvb_dmx_swfilter); void dvb_dmx_swfilter_204(struct dvb_demux *demux, const u8 *buf, size_t count) { - unsigned long flags; int p = 0, i, j; u8 tmppack[188]; - spin_lock_irqsave(&demux->lock, flags); + spin_lock(&demux->lock); if (demux->tsbufp) { i = demux->tsbufp; @@ -504,7 +500,7 @@ void dvb_dmx_swfilter_204(struct dvb_demux *demux, const u8 *buf, size_t count) } bailout: - spin_unlock_irqrestore(&demux->lock, flags); + spin_unlock(&demux->lock); } EXPORT_SYMBOL(dvb_dmx_swfilter_204); -- 2.41.1