Subject: + rapidio-tsi721-fix-tasklet-termination-in-dma-channel-release.patch
added to -mm tree
To:
[email protected],[email protected],[email protected],[email protected],[email protected],[email protected]
From: [email protected]
Date: Fri, 21 Feb 2014 12:10:38 -0800
The patch titled
Subject: rapidio/tsi721: fix tasklet termination in dma channel release
has been added to the -mm tree. Its filename is
rapidio-tsi721-fix-tasklet-termination-in-dma-channel-release.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/rapidio-tsi721-fix-tasklet-termination-in-dma-channel-release.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/rapidio-tsi721-fix-tasklet-termination-in-dma-channel-release.patch
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------------------------------------------------------
From: Alexandre Bounine <[email protected]>
Subject: rapidio/tsi721: fix tasklet termination in dma channel release
This patch is a modification of the patch originally proposed by Xiaotian
Feng <[email protected]>: https://lkml.org/lkml/2012/11/5/413 This new
version disables DMA channel interrupts and ensures that the tasklet wil
not be scheduled again before calling tasklet_kill().
Unfortunately the updated patch was not released at that time due to
planned rework of Tsi721 mport driver to use threaded interrupts (which
has yet to happen). Recently the issue was reported again:
https://lkml.org/lkml/2014/2/19/762.
Description from the original Xiaotian's patch:
"Some drivers use tasklet_disable in device remove/release process,
tasklet_disable will inc tasklet->count and return. If the tasklet is not
handled yet under some softirq pressure, the tasklet will be placed on the
tasklet_vec, never have a chance to be excuted. This might lead to a
heavy loaded ksoftirqd, wakeup with pending_softirq, but tasklet is
disabled. tasklet_kill should be used in this case."
This patch is applicable to kernel versions starting from v3.5.
Signed-off-by: Alexandre Bounine <[email protected]>
Cc: Matt Porter <[email protected]>
Cc: Xiaotian Feng <[email protected]>
Reviewed-by: Thomas Gleixner <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: <[email protected]> [3.5+]
Signed-off-by: Andrew Morton <[email protected]>
---
drivers/rapidio/devices/tsi721.h | 1 +
drivers/rapidio/devices/tsi721_dma.c | 25 ++++++++++++++++++-------
2 files changed, 19 insertions(+), 7 deletions(-)
diff -puN
drivers/rapidio/devices/tsi721.h~rapidio-tsi721-fix-tasklet-termination-in-dma-channel-release
drivers/rapidio/devices/tsi721.h
---
a/drivers/rapidio/devices/tsi721.h~rapidio-tsi721-fix-tasklet-termination-in-dma-channel-release
+++ a/drivers/rapidio/devices/tsi721.h
@@ -678,6 +678,7 @@ struct tsi721_bdma_chan {
struct list_head free_list;
dma_cookie_t completed_cookie;
struct tasklet_struct tasklet;
+ bool active;
};
#endif /* CONFIG_RAPIDIO_DMA_ENGINE */
diff -puN
drivers/rapidio/devices/tsi721_dma.c~rapidio-tsi721-fix-tasklet-termination-in-dma-channel-release
drivers/rapidio/devices/tsi721_dma.c
---
a/drivers/rapidio/devices/tsi721_dma.c~rapidio-tsi721-fix-tasklet-termination-in-dma-channel-release
+++ a/drivers/rapidio/devices/tsi721_dma.c
@@ -206,8 +206,8 @@ void tsi721_bdma_handler(struct tsi721_b
{
/* Disable BDMA channel interrupts */
iowrite32(0, bdma_chan->regs + TSI721_DMAC_INTE);
-
- tasklet_schedule(&bdma_chan->tasklet);
+ if (bdma_chan->active)
+ tasklet_schedule(&bdma_chan->tasklet);
}
#ifdef CONFIG_PCI_MSI
@@ -562,7 +562,7 @@ static int tsi721_alloc_chan_resources(s
}
#endif /* CONFIG_PCI_MSI */
- tasklet_enable(&bdma_chan->tasklet);
+ bdma_chan->active = true;
tsi721_bdma_interrupt_enable(bdma_chan, 1);
return bdma_chan->bd_num - 1;
@@ -589,14 +589,25 @@ static void tsi721_free_chan_resources(s
BUG_ON(!list_empty(&bdma_chan->active_list));
BUG_ON(!list_empty(&bdma_chan->queue));
- tasklet_disable(&bdma_chan->tasklet);
+ tsi721_bdma_interrupt_enable(bdma_chan, 0);
+ bdma_chan->active = false;
+
+#ifdef CONFIG_PCI_MSI
+ if (priv->flags & TSI721_USING_MSIX) {
+ synchronize_irq(priv->msix[TSI721_VECT_DMA0_DONE +
+ bdma_chan->id].vector);
+ synchronize_irq(priv->msix[TSI721_VECT_DMA0_INT +
+ bdma_chan->id].vector);
+ } else
+#endif
+ synchronize_irq(priv->pdev->irq);
+
+ tasklet_kill(&bdma_chan->tasklet);
spin_lock_bh(&bdma_chan->lock);
list_splice_init(&bdma_chan->free_list, &list);
spin_unlock_bh(&bdma_chan->lock);
- tsi721_bdma_interrupt_enable(bdma_chan, 0);
-
#ifdef CONFIG_PCI_MSI
if (priv->flags & TSI721_USING_MSIX) {
free_irq(priv->msix[TSI721_VECT_DMA0_DONE +
@@ -790,6 +801,7 @@ int tsi721_register_dma(struct tsi721_de
bdma_chan->dchan.cookie = 1;
bdma_chan->dchan.chan_id = i;
bdma_chan->id = i;
+ bdma_chan->active = false;
spin_lock_init(&bdma_chan->lock);
@@ -799,7 +811,6 @@ int tsi721_register_dma(struct tsi721_de
tasklet_init(&bdma_chan->tasklet, tsi721_dma_tasklet,
(unsigned long)bdma_chan);
- tasklet_disable(&bdma_chan->tasklet);
list_add_tail(&bdma_chan->dchan.device_node,
&mport->dma.channels);
}
_
Patches currently in -mm which might be from [email protected] are
rapidio-tsi721-fix-tasklet-termination-in-dma-channel-release.patch
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