vfio/pci: Pass eventfd context object through irqfd

Further avoid lookup of the context object by passing it through the
irqfd data field.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20240401195406.3720453-3-alex.williamson@redhat.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

drivers/vfio/pci/vfio_pci_intrs.c

@@ -85,19 +85,14 @@ vfio_irq_ctx_alloc(struct vfio_pci_core_device *vdev, unsigned long index)
 /*
  * INTx
  */
-static void vfio_send_intx_eventfd(void *opaque, void *unused)
+static void vfio_send_intx_eventfd(void *opaque, void *data)
 {
 	struct vfio_pci_core_device *vdev = opaque;
 
 	if (likely(is_intx(vdev) && !vdev->virq_disabled)) {
-		struct vfio_pci_irq_ctx *ctx;
-		struct eventfd_ctx *trigger;
+		struct vfio_pci_irq_ctx *ctx = data;
+		struct eventfd_ctx *trigger = READ_ONCE(ctx->trigger);
 
-		ctx = vfio_irq_ctx_get(vdev, 0);
-		if (WARN_ON_ONCE(!ctx))
-			return;
-
-		trigger = READ_ONCE(ctx->trigger);
 		if (likely(trigger))
 			eventfd_signal(trigger);
 	}
@@ -167,11 +162,11 @@ bool vfio_pci_intx_mask(struct vfio_pci_core_device *vdev)
  * a signal is necessary, which can then be handled via a work queue
  * or directly depending on the caller.
  */
-static int vfio_pci_intx_unmask_handler(void *opaque, void *unused)
+static int vfio_pci_intx_unmask_handler(void *opaque, void *data)
 {
 	struct vfio_pci_core_device *vdev = opaque;
 	struct pci_dev *pdev = vdev->pdev;
-	struct vfio_pci_irq_ctx *ctx;
+	struct vfio_pci_irq_ctx *ctx = data;
 	unsigned long flags;
 	int ret = 0;
 
@@ -187,10 +182,6 @@ static int vfio_pci_intx_unmask_handler(void *opaque, void *unused)
 		goto out_unlock;
 	}
 
-	ctx = vfio_irq_ctx_get(vdev, 0);
-	if (WARN_ON_ONCE(!ctx))
-		goto out_unlock;
-
 	if (ctx->masked && !vdev->virq_disabled) {
 		/*
 		 * A pending interrupt here would immediately trigger,
@@ -214,10 +205,12 @@ static int vfio_pci_intx_unmask_handler(void *opaque, void *unused)
 
 static void __vfio_pci_intx_unmask(struct vfio_pci_core_device *vdev)
 {
+	struct vfio_pci_irq_ctx *ctx = vfio_irq_ctx_get(vdev, 0);
+
 	lockdep_assert_held(&vdev->igate);
 
-	if (vfio_pci_intx_unmask_handler(vdev, NULL) > 0)
-		vfio_send_intx_eventfd(vdev, NULL);
+	if (vfio_pci_intx_unmask_handler(vdev, ctx) > 0)
+		vfio_send_intx_eventfd(vdev, ctx);
 }
 
 void vfio_pci_intx_unmask(struct vfio_pci_core_device *vdev)
@@ -249,7 +242,7 @@ static irqreturn_t vfio_intx_handler(int irq, void *dev_id)
 	spin_unlock_irqrestore(&vdev->irqlock, flags);
 
 	if (ret == IRQ_HANDLED)
-		vfio_send_intx_eventfd(vdev, NULL);
+		vfio_send_intx_eventfd(vdev, ctx);
 
 	return ret;
 }
@@ -604,7 +597,7 @@ static int vfio_pci_set_intx_unmask(struct vfio_pci_core_device *vdev,
 		if (fd >= 0)
 			return vfio_virqfd_enable((void *) vdev,
 						  vfio_pci_intx_unmask_handler,
-						  vfio_send_intx_eventfd, NULL,
+						  vfio_send_intx_eventfd, ctx,
 						  &ctx->unmask, fd);
 
 		vfio_virqfd_disable(&ctx->unmask);
@@ -671,11 +664,11 @@ static int vfio_pci_set_intx_trigger(struct vfio_pci_core_device *vdev,
 		return -EINVAL;
 
 	if (flags & VFIO_IRQ_SET_DATA_NONE) {
-		vfio_send_intx_eventfd(vdev, NULL);
+		vfio_send_intx_eventfd(vdev, vfio_irq_ctx_get(vdev, 0));
 	} else if (flags & VFIO_IRQ_SET_DATA_BOOL) {
 		uint8_t trigger = *(uint8_t *)data;
 		if (trigger)
-			vfio_send_intx_eventfd(vdev, NULL);
+			vfio_send_intx_eventfd(vdev, vfio_irq_ctx_get(vdev, 0));
 	}
 	return 0;
 }