@@ -77,7 +77,8 @@ static irqreturn_t ioat_dma_do_interrupt(int irq, void *data)
attnstatus = readl(instance->reg_base + IOAT_ATTNSTATUS_OFFSET);
for_each_set_bit(bit, &attnstatus, BITS_PER_LONG) {
chan = ioat_chan_by_index(instance, bit);
- tasklet_schedule(&chan->cleanup_task);
+ if (test_bit(IOAT_RUN, &chan->state))
+ tasklet_schedule(&chan->cleanup_task);
}
writeb(intrctrl, instance->reg_base + IOAT_INTRCTRL_OFFSET);
@@ -93,7 +94,8 @@ static irqreturn_t ioat_dma_do_interrupt_msix(int irq, void *data)
{
struct ioat_chan_common *chan = data;
- tasklet_schedule(&chan->cleanup_task);
+ if (test_bit(IOAT_RUN, &chan->state))
+ tasklet_schedule(&chan->cleanup_task);
return IRQ_HANDLED;
}
@@ -116,7 +118,6 @@ void ioat_init_channel(struct ioatdma_device *device, struct ioat_chan_common *c
chan->timer.function = device->timer_fn;
chan->timer.data = data;
tasklet_init(&chan->cleanup_task, device->cleanup_fn, data);
- tasklet_disable(&chan->cleanup_task);
}
/**
@@ -354,13 +355,43 @@ static int ioat1_dma_alloc_chan_resources(struct dma_chan *c)
writel(((u64) chan->completion_dma) >> 32,
chan->reg_base + IOAT_CHANCMP_OFFSET_HIGH);
- tasklet_enable(&chan->cleanup_task);
+ set_bit(IOAT_RUN, &chan->state);
ioat1_dma_start_null_desc(ioat); /* give chain to dma device */
dev_dbg(to_dev(chan), "%s: allocated %d descriptors\n",
__func__, ioat->desccount);
return ioat->desccount;
}
+void ioat_stop(struct ioat_chan_common *chan)
+{
+ struct ioatdma_device *device = chan->device;
+ struct pci_dev *pdev = device->pdev;
+ int chan_id = chan_num(chan);
+
+ /* 1/ stop irq from firing tasklets
+ * 2/ stop the tasklet from re-arming irqs
+ */
+ clear_bit(IOAT_RUN, &chan->state);
+
+ /* flush inflight interrupts */
+#ifdef CONFIG_PCI_MSI
+ if (pdev->msix_enabled) {
+ struct msix_entry *msix = &device->msix_entries[chan_id];
+ synchronize_irq(msix->vector);
+ } else
+#endif
+ synchronize_irq(pdev->irq);
+
+ /* flush inflight timers */
+ del_timer_sync(&chan->timer);
+
+ /* flush inflight tasklet runs */
+ tasklet_kill(&chan->cleanup_task);
+
+ /* final cleanup now that everything is quiesced and can't re-arm */
+ device->cleanup_fn((unsigned long) &chan->common);
+}
+
/**
* ioat1_dma_free_chan_resources - release all the descriptors
* @chan: the channel to be cleaned
@@ -379,9 +410,7 @@ static void ioat1_dma_free_chan_resources(struct dma_chan *c)
if (ioat->desccount == 0)
return;
- tasklet_disable(&chan->cleanup_task);
- del_timer_sync(&chan->timer);
- ioat1_cleanup(ioat);
+ ioat_stop(chan);
/* Delay 100ms after reset to allow internal DMA logic to quiesce
* before removing DMA descriptor resources.
@@ -526,8 +555,11 @@ ioat1_dma_prep_memcpy(struct dma_chan *c, dma_addr_t dma_dest,
static void ioat1_cleanup_event(unsigned long data)
{
struct ioat_dma_chan *ioat = to_ioat_chan((void *) data);
+ struct ioat_chan_common *chan = &ioat->base;
ioat1_cleanup(ioat);
+ if (!test_bit(IOAT_RUN, &chan->state))
+ return;
writew(IOAT_CHANCTRL_RUN, ioat->base.reg_base + IOAT_CHANCTRL_OFFSET);
}
@@ -320,6 +320,7 @@ bool ioat_cleanup_preamble(struct ioat_chan_common *chan,
dma_addr_t *phys_complete);
void ioat_kobject_add(struct ioatdma_device *device, struct kobj_type *type);
void ioat_kobject_del(struct ioatdma_device *device);
+void ioat_stop(struct ioat_chan_common *chan);
extern const struct sysfs_ops ioat_sysfs_ops;
extern struct ioat_sysfs_entry ioat_version_attr;
extern struct ioat_sysfs_entry ioat_cap_attr;
@@ -190,8 +190,11 @@ static void ioat2_cleanup(struct ioat2_dma_chan *ioat)
void ioat2_cleanup_event(unsigned long data)
{
struct ioat2_dma_chan *ioat = to_ioat2_chan((void *) data);
+ struct ioat_chan_common *chan = &ioat->base;
ioat2_cleanup(ioat);
+ if (!test_bit(IOAT_RUN, &chan->state))
+ return;
writew(IOAT_CHANCTRL_RUN, ioat->base.reg_base + IOAT_CHANCTRL_OFFSET);
}
@@ -538,10 +541,10 @@ int ioat2_alloc_chan_resources(struct dma_chan *c)
ioat->issued = 0;
ioat->tail = 0;
ioat->alloc_order = order;
+ set_bit(IOAT_RUN, &chan->state);
spin_unlock_bh(&ioat->prep_lock);
spin_unlock_bh(&chan->cleanup_lock);
- tasklet_enable(&chan->cleanup_task);
ioat2_start_null_desc(ioat);
/* check that we got off the ground */
@@ -551,7 +554,6 @@ int ioat2_alloc_chan_resources(struct dma_chan *c)
} while (i++ < 20 && !is_ioat_active(status) && !is_ioat_idle(status));
if (is_ioat_active(status) || is_ioat_idle(status)) {
- set_bit(IOAT_RUN, &chan->state);
return 1 << ioat->alloc_order;
} else {
u32 chanerr = readl(chan->reg_base + IOAT_CHANERR_OFFSET);
@@ -794,11 +796,8 @@ void ioat2_free_chan_resources(struct dma_chan *c)
if (!ioat->ring)
return;
- tasklet_disable(&chan->cleanup_task);
- del_timer_sync(&chan->timer);
- device->cleanup_fn((unsigned long) c);
+ ioat_stop(chan);
device->reset_hw(chan);
- clear_bit(IOAT_RUN, &chan->state);
spin_lock_bh(&chan->cleanup_lock);
spin_lock_bh(&ioat->prep_lock);
@@ -325,8 +325,11 @@ 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);
}
This is a note to let you know that I have just added a patch titled ioat: fix tasklet tear down to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue This patch is scheduled to be released in version 3.8.13.21. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.8.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ------ From 9c16e27e5f4e452d062f6ea33ef4671ceaedc9c6 Mon Sep 17 00:00:00 2001 From: Dan Williams <dan.j.williams@intel.com> Date: Wed, 19 Feb 2014 16:19:35 -0800 Subject: 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> [bwh: Backported to 3.2: - Adjust context - As there is no ioatdma_device::irq_mode member, check pci_dev::msix_enabled instead] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Signed-off-by: Luis Henriques <luis.henriques@canonical.com> Acked-by: Brad Figg <brad.figg@canonical.com> Acked-by: Tim Gardner <tim.gardner@canonical.com> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- drivers/dma/ioat/dma.c | 46 +++++++++++++++++++++++++++++++++++++++------- drivers/dma/ioat/dma.h | 1 + drivers/dma/ioat/dma_v2.c | 11 +++++------ drivers/dma/ioat/dma_v3.c | 3 +++ 4 files changed, 48 insertions(+), 13 deletions(-) -- 1.8.3.2