From da87ca4d4ca101f177fffd84f1f0a5e4c0343557 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Wed, 19 Feb 2014 16:19:35 -0800 Subject: ioat: fix tasklet tear down 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 Cc: Steven Rostedt Cc: Reported-by: Mike Galbraith Reported-by: Stanislav Fomichev Tested-by: Mike Galbraith Tested-by: Stanislav Fomichev Reviewed-by: Thomas Gleixner Signed-off-by: Dan Williams --- drivers/dma/ioat/dma_v3.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'drivers/dma/ioat/dma_v3.c') diff --git a/drivers/dma/ioat/dma_v3.c b/drivers/dma/ioat/dma_v3.c index 820817e97e62..b9b38a1cf92f 100644 --- a/drivers/dma/ioat/dma_v3.c +++ b/drivers/dma/ioat/dma_v3.c @@ -464,8 +464,11 @@ 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); } -- cgit v1.2.1