i915: make inject_virtual_interrupt() void

The single caller of inject_virtual_interrupt() ignores the return value
anyway. This allows us to simplify eventfd_signal() in follow-up
patches.

Link: https://lore.kernel.org/r/20231122-vfs-eventfd-signal-v2-1-bd549b14ce0c@kernel.orgReviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Christian Brauner <brauner@kernel.org>

drivers/gpu/drm/i915/gvt/interrupt.c

@@ -422,7 +422,7 @@ static void init_irq_map(struct intel_gvt_irq *irq)
 #define MSI_CAP_DATA(offset) (offset + 8)
 #define MSI_CAP_EN 0x1
 
-static int inject_virtual_interrupt(struct intel_vgpu *vgpu)
+static void inject_virtual_interrupt(struct intel_vgpu *vgpu)
 {
 	unsigned long offset = vgpu->gvt->device_info.msi_cap_offset;
 	u16 control, data;
@@ -434,10 +434,10 @@ static int inject_virtual_interrupt(struct intel_vgpu *vgpu)
 
 	/* Do not generate MSI if MSIEN is disabled */
 	if (!(control & MSI_CAP_EN))
-		return 0;
+		return;
 
 	if (WARN(control & GENMASK(15, 1), "only support one MSI format\n"))
-		return -EINVAL;
+		return;
 
 	trace_inject_msi(vgpu->id, addr, data);
 
@@ -451,10 +451,9 @@ static int inject_virtual_interrupt(struct intel_vgpu *vgpu)
 	 * returned and don't inject interrupt into guest.
 	 */
 	if (!test_bit(INTEL_VGPU_STATUS_ATTACHED, vgpu->status))
-		return -ESRCH;
-	if (vgpu->msi_trigger && eventfd_signal(vgpu->msi_trigger, 1) != 1)
-		return -EFAULT;
-	return 0;
+		return;
+	if (vgpu->msi_trigger)
+		eventfd_signal(vgpu->msi_trigger, 1);
 }
 
 static void propagate_event(struct intel_gvt_irq *irq,