[PATCH -next] virt: vmgenid: fix return value check in vmgenid_acpi_add()

[Wei Yongjun <weiyongjun1@xxxxxxxxxx>]

In case of error, the function devm_memremap() returns ERR_PTR()
and never returns NULL. The NULL test in the return value check
should be replaced with IS_ERR().

Fixes: d54207b61470 ("virt: vmgenid: introduce driver for reinitializing RNG on VM fork")
Reported-by: Hulk Robot <hulkci@xxxxxxxxxx>
Signed-off-by: Wei Yongjun <weiyongjun1@xxxxxxxxxx>
---
 drivers/virt/vmgenid.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/virt/vmgenid.c b/drivers/virt/vmgenid.c
index b503c210c2d7..344f6fcc01da 100644
--- a/drivers/virt/vmgenid.c
+++ b/drivers/virt/vmgenid.c
@@ -50,8 +50,8 @@ static int vmgenid_acpi_add(struct acpi_device *device)
 	phys_addr = (obj->package.elements[0].integer.value << 0) |
 		    (obj->package.elements[1].integer.value << 32);
 	state->next_id = devm_memremap(&device->dev, phys_addr, VMGENID_SIZE, MEMREMAP_WB);
-	if (!state->next_id) {
-		ret = -ENOMEM;
+	if (IS_ERR(state->next_id)) {
+		ret = PTR_ERR(state->next_id);
 		goto out;
 	}