powerpc/powernv: Disable interrupts while taking phb->lock

We need to disable interrupts when taking the phb->lock. Otherwise
we could deadlock with pci_lock taken from an interrupt.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 14 insertions, 8 deletions

diff --git a/arch/powerpc/platforms/powernv/pci.c b/arch/powerpc/platforms/powernv/pci.c
index a70bc1e385eb..f92b9ef7340e 100644
--- a/arch/powerpc/platforms/powernv/pci.c
+++ b/arch/powerpc/platforms/powernv/pci.c
@@ -52,32 +52,38 @@ static int pnv_msi_check_device(struct pci_dev* pdev, int nvec, int type)
 
 static unsigned int pnv_get_one_msi(struct pnv_phb *phb)
 {
-        unsigned int id;
+        unsigned long flags;
+        unsigned int id, rc;
+
+        spin_lock_irqsave(&phb->lock, flags);
 
-        spin_lock(&phb->lock);
         id = find_next_zero_bit(phb->msi_map, phb->msi_count, phb->msi_next);
         if (id >= phb->msi_count && phb->msi_next)
                 id = find_next_zero_bit(phb->msi_map, phb->msi_count, 0);
         if (id >= phb->msi_count) {
-                spin_unlock(&phb->lock);
-                return 0;
+                rc = 0;
+                goto out;
         }
         __set_bit(id, phb->msi_map);
-        spin_unlock(&phb->lock);
-        return id + phb->msi_base;
+        rc = id + phb->msi_base;
+out:
+        spin_unlock_irqrestore(&phb->lock, flags);
+        return rc;
 }
 
 static void pnv_put_msi(struct pnv_phb *phb, unsigned int hwirq)
 {
+        unsigned long flags;
         unsigned int id;
 
         if (WARN_ON(hwirq < phb->msi_base ||
                     hwirq >= (phb->msi_base + phb->msi_count)))
                 return;
         id = hwirq - phb->msi_base;
-        spin_lock(&phb->lock);
+
+        spin_lock_irqsave(&phb->lock, flags);
         __clear_bit(id, phb->msi_map);
-        spin_unlock(&phb->lock);
+        spin_unlock_irqrestore(&phb->lock, flags);
 }
 
 static int pnv_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type)