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Subject[PATCH] IB/ehca: Fix locking for shca_list_lock
Date
shca_list_lock is taken from softirq context in ehca_poll_eqs, so we need to
lock IRQ safe elsewhere.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Joachim Fenkes <fenkes@de.ibm.com>
---

On Friday 21 November 2008 17:02, Johannes Berg wrote:
> On Fri, 2008-11-21 at 16:37 +0100, Joachim Fenkes wrote:
>
> > + u64 flags;
>
> > - spin_lock(&shca_list_lock);
> > + spin_lock_irqsave(&shca_list_lock, flags);
>
> That's wrong and I think will give a warning on all machines where
> u64 != unsigned long. Might not particularly matter in this case.

Doesn't matter for a ppc64 only driver, but you're right nonetheless. Thanks.

> Also, generally it seems wrong to say "fix lockdep failure" when the
> patch really fixes a bug that lockdep happened to find.

Whatever -- changed.

Here's the updated patch.

Regards,
Joachim


drivers/infiniband/hw/ehca/ehca_main.c | 17 ++++++++++-------
1 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/drivers/infiniband/hw/ehca/ehca_main.c b/drivers/infiniband/hw/ehca/ehca_main.c
index bb02a86..169aa1a 100644
--- a/drivers/infiniband/hw/ehca/ehca_main.c
+++ b/drivers/infiniband/hw/ehca/ehca_main.c
@@ -717,6 +717,7 @@ static int __devinit ehca_probe(struct of_device *dev,
const u64 *handle;
struct ib_pd *ibpd;
int ret, i, eq_size;
+ unsigned long flags;

handle = of_get_property(dev->node, "ibm,hca-handle", NULL);
if (!handle) {
@@ -830,9 +831,9 @@ static int __devinit ehca_probe(struct of_device *dev,
ehca_err(&shca->ib_device,
"Cannot create device attributes ret=%d", ret);

- spin_lock(&shca_list_lock);
+ spin_lock_irqsave(&shca_list_lock, flags);
list_add(&shca->shca_list, &shca_list);
- spin_unlock(&shca_list_lock);
+ spin_unlock_irqrestore(&shca_list_lock, flags);

return 0;

@@ -878,6 +879,7 @@ probe1:
static int __devexit ehca_remove(struct of_device *dev)
{
struct ehca_shca *shca = dev->dev.driver_data;
+ unsigned long flags;
int ret;

sysfs_remove_group(&dev->dev.kobj, &ehca_dev_attr_grp);
@@ -915,9 +917,9 @@ static int __devexit ehca_remove(struct of_device *dev)

ib_dealloc_device(&shca->ib_device);

- spin_lock(&shca_list_lock);
+ spin_lock_irqsave(&shca_list_lock, flags);
list_del(&shca->shca_list);
- spin_unlock(&shca_list_lock);
+ spin_unlock_irqrestore(&shca_list_lock, flags);

return ret;
}
@@ -975,6 +977,7 @@ static int ehca_mem_notifier(struct notifier_block *nb,
unsigned long action, void *data)
{
static unsigned long ehca_dmem_warn_time;
+ unsigned long flags;

switch (action) {
case MEM_CANCEL_OFFLINE:
@@ -985,12 +988,12 @@ static int ehca_mem_notifier(struct notifier_block *nb,
case MEM_GOING_ONLINE:
case MEM_GOING_OFFLINE:
/* only ok if no hca is attached to the lpar */
- spin_lock(&shca_list_lock);
+ spin_lock_irqsave(&shca_list_lock, flags);
if (list_empty(&shca_list)) {
- spin_unlock(&shca_list_lock);
+ spin_unlock_irqrestore(&shca_list_lock, flags);
return NOTIFY_OK;
} else {
- spin_unlock(&shca_list_lock);
+ spin_unlock_irqrestore(&shca_list_lock, flags);
if (printk_timed_ratelimit(&ehca_dmem_warn_time,
30 * 1000))
ehca_gen_err("DMEM operations are not allowed"
--
1.5.5




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