diff options
| author | Dan Williams <dan.j.williams@intel.com> | 2014-02-19 16:19:35 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-03-06 21:30:14 -0800 |
| commit | e9ba61f0ddacaa5efd7dd4619d828d2466638913 (patch) | |
| tree | 791346a65b9a2b8856f9591647e96f85f47fec4c /drivers/dma/ioat/dma_v3.c | |
| parent | b4cd4961cf9c455d1299c21a353ae3e81a23b872 (diff) | |
ioat: fix tasklet tear down
commit da87ca4d4ca101f177fffd84f1f0a5e4c0343557 upstream.
Since commit 77873803363c "net_dma: mark broken" we no longer pin dma
engines active for the network-receive-offload use case. As a result
the ->free_chan_resources() that occurs after the driver self test no
longer has a NET_DMA induced ->alloc_chan_resources() to back it up. A
late firing irq can lead to ksoftirqd spinning indefinitely due to the
tasklet_disable() performed by ->free_chan_resources(). Only
->alloc_chan_resources() can clear this condition in affected kernels.
This problem has been present since commit 3e037454bcfa "I/OAT: Add
support for MSI and MSI-X" in 2.6.24, but is now exposed. Given the
NET_DMA use case is deprecated we can revisit moving the driver to use
threaded irqs. For now, just tear down the irq and tasklet properly by:
1/ Disable the irq from triggering the tasklet
2/ Disable the irq from re-arming
3/ Flush inflight interrupts
4/ Flush the timer
5/ Flush inflight tasklets
References:
https://lkml.org/lkml/2014/1/27/282
https://lkml.org/lkml/2014/2/19/672
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Steven Rostedt <rostedt@goodmis.org>
Reported-by: Mike Galbraith <bitbucket@online.de>
Reported-by: Stanislav Fomichev <stfomichev@yandex-team.ru>
Tested-by: Mike Galbraith <bitbucket@online.de>
Tested-by: Stanislav Fomichev <stfomichev@yandex-team.ru>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/dma/ioat/dma_v3.c')
| -rw-r--r-- | drivers/dma/ioat/dma_v3.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/dma/ioat/dma_v3.c b/drivers/dma/ioat/dma_v3.c index fa43a42ccc86..38b94b393c6c 100644 --- a/drivers/dma/ioat/dma_v3.c +++ b/drivers/dma/ioat/dma_v3.c @@ -635,8 +635,11 @@ static void ioat3_cleanup(struct ioat2_dma_chan *ioat) static void ioat3_cleanup_event(unsigned long data) { struct ioat2_dma_chan *ioat = to_ioat2_chan((void *) data); + struct ioat_chan_common *chan = &ioat->base; ioat3_cleanup(ioat); + if (!test_bit(IOAT_RUN, &chan->state)) + return; writew(IOAT_CHANCTRL_RUN, ioat->base.reg_base + IOAT_CHANCTRL_OFFSET); } |