[PATCH resend] ib/ehca: rework destroy_eq()

[Alexander Schmidt <alexs@linux.vnet.ibm.com>]

The ibmebus_free_irq() function, which might sleep, was called with
interrupts disabled. To ship around this, make sure that no interrupts
are running by killing the interrupt tasklet. Also lock the shca_list_lock to
protect against the poll_eqs_timer running concurrently.

Signed-off-by: Alexander Schmidt <alexs@linux.vnet.ibm.com>
---
Hi Roland,

seems like I used your old mail address and I forgot to add the linux-rdma
list.

Please apply this for your "next" tree, thanks.

 drivers/infiniband/hw/ehca/ehca_classes.h |    1 +
 drivers/infiniband/hw/ehca/ehca_eq.c      |    9 ++++++---
 drivers/infiniband/hw/ehca/ehca_main.c    |    2 +-
 3 files changed, 8 insertions(+), 4 deletions(-)

--- linux-2.6.orig/drivers/infiniband/hw/ehca/ehca_eq.c
+++ linux-2.6/drivers/infiniband/hw/ehca/ehca_eq.c
@@ -169,12 +169,15 @@ int ehca_destroy_eq(struct ehca_shca *sh
 	unsigned long flags;
 	u64 h_ret;

-	spin_lock_irqsave(&eq->spinlock, flags);
 	ibmebus_free_irq(eq->ist, (void *)shca);

-	h_ret = hipz_h_destroy_eq(shca->ipz_hca_handle, eq);
+	spin_lock_irqsave(&shca_list_lock, flags);
+	eq->is_initialized = 0;
+	spin_unlock_irqrestore(&shca_list_lock, flags);
+
+	tasklet_kill(&eq->interrupt_task);

-	spin_unlock_irqrestore(&eq->spinlock, flags);
+	h_ret = hipz_h_destroy_eq(shca->ipz_hca_handle, eq);

 	if (h_ret != H_SUCCESS) {
 		ehca_err(&shca->ib_device, "Can't free EQ resources.");
--- linux-2.6.orig/drivers/infiniband/hw/ehca/ehca_classes.h
+++ linux-2.6/drivers/infiniband/hw/ehca/ehca_classes.h
@@ -375,6 +375,7 @@ extern rwlock_t ehca_qp_idr_lock;
 extern rwlock_t ehca_cq_idr_lock;
 extern struct idr ehca_qp_idr;
 extern struct idr ehca_cq_idr;
+extern spinlock_t shca_list_lock;

 extern int ehca_static_rate;
 extern int ehca_port_act_time;
--- linux-2.6.orig/drivers/infiniband/hw/ehca/ehca_main.c
+++ linux-2.6/drivers/infiniband/hw/ehca/ehca_main.c
@@ -123,7 +123,7 @@ DEFINE_IDR(ehca_qp_idr);
 DEFINE_IDR(ehca_cq_idr);

 static LIST_HEAD(shca_list); /* list of all registered ehcas */
-static DEFINE_SPINLOCK(shca_list_lock);
+DEFINE_SPINLOCK(shca_list_lock);

 static struct timer_list poll_eqs_timer;