[PATCH 1/2] Revert "virtio-pci: harden INTX interrupts"

[Jason Wang]

This reverts commit 080cd7c3ac8701081d143a15ba17dd9475313188. Since
the MSI-X interrupts hardening will be reverted in the next patch. We
will rework the interrupt hardening in the future.

Fixes: 080cd7c3ac87 ("virtio-pci: harden INTX interrupts")
Signed-off-by: Jason Wang <jasow...@redhat.com>
---
 drivers/virtio/virtio_pci_common.c | 23 ++---------------------
 drivers/virtio/virtio_pci_common.h |  1 -
 2 files changed, 2 insertions(+), 22 deletions(-)

diff --git a/drivers/virtio/virtio_pci_common.c 
b/drivers/virtio/virtio_pci_common.c
index fdbde1db5ec5..3f51fdb7be45 100644
--- a/drivers/virtio/virtio_pci_common.c
+++ b/drivers/virtio/virtio_pci_common.c
@@ -30,16 +30,8 @@ void vp_disable_cbs(struct virtio_device *vdev)
        struct virtio_pci_device *vp_dev = to_vp_device(vdev);
        int i;
 
-       if (vp_dev->intx_enabled) {
-               /*
-                * The below synchronize() guarantees that any
-                * interrupt for this line arriving after
-                * synchronize_irq() has completed is guaranteed to see
-                * intx_soft_enabled == false.
-                */
-               WRITE_ONCE(vp_dev->intx_soft_enabled, false);
+       if (vp_dev->intx_enabled)
                synchronize_irq(vp_dev->pci_dev->irq);
-       }
 
        for (i = 0; i < vp_dev->msix_vectors; ++i)
                disable_irq(pci_irq_vector(vp_dev->pci_dev, i));
@@ -51,16 +43,8 @@ void vp_enable_cbs(struct virtio_device *vdev)
        struct virtio_pci_device *vp_dev = to_vp_device(vdev);
        int i;
 
-       if (vp_dev->intx_enabled) {
-               disable_irq(vp_dev->pci_dev->irq);
-               /*
-                * The above disable_irq() provides TSO ordering and
-                * as such promotes the below store to store-release.
-                */
-               WRITE_ONCE(vp_dev->intx_soft_enabled, true);
-               enable_irq(vp_dev->pci_dev->irq);
+       if (vp_dev->intx_enabled)
                return;
-       }
 
        for (i = 0; i < vp_dev->msix_vectors; ++i)
                enable_irq(pci_irq_vector(vp_dev->pci_dev, i));
@@ -113,9 +97,6 @@ static irqreturn_t vp_interrupt(int irq, void *opaque)
        struct virtio_pci_device *vp_dev = opaque;
        u8 isr;
 
-       if (!READ_ONCE(vp_dev->intx_soft_enabled))
-               return IRQ_NONE;
-
        /* reading the ISR has the effect of also clearing it so it's very
         * important to save off the value. */
        isr = ioread8(vp_dev->isr);
diff --git a/drivers/virtio/virtio_pci_common.h 
b/drivers/virtio/virtio_pci_common.h
index 23f6c5c678d5..d3c6f72c7390 100644
--- a/drivers/virtio/virtio_pci_common.h
+++ b/drivers/virtio/virtio_pci_common.h
@@ -63,7 +63,6 @@ struct virtio_pci_device {
        /* MSI-X support */
        int msix_enabled;
        int intx_enabled;
-       bool intx_soft_enabled;
        cpumask_var_t *msix_affinity_masks;
        /* Name strings for interrupts. This size should be enough,
         * and I'm too lazy to allocate each name separately. */
-- 
2.25.1

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