pci: Add comment for pci_add_capability2()

Comments for pci_add_capability2() to explain the return
value. This may help to make a correct return value check
for its callers.

Cc: mst@redhat.com
Cc: marcel@redhat.com
Cc: armbru@redhat.com
Signed-off-by: Mao Zhongyi <maozy.fnst@cn.fujitsu.com>
Reviewed-by: Marcel Apfelbaum <marcel@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index 3c24888870959997329e8d5c2effc6d01960f6d5..3370b76164123bf35246d09eadd68a2e3f9af71f 100644 (file)
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -2276,6 +2276,12 @@ int pci_add_capability(PCIDevice *pdev, uint8_t cap_id,
     return ret;
 }
 
+/*
+ * On success, pci_add_capability2() returns a positive value
+ * that the offset of the pci capability.
+ * On failure, it sets an error and returns a negative error
+ * code.
+ */
 int pci_add_capability2(PCIDevice *pdev, uint8_t cap_id,
                        uint8_t offset, uint8_t size,
                        Error **errp)