bus/vmbus: handle EOF on IRQ read

This function is not used by netvsc driver yet.
Still the code should handle case where device driver returns
zero (due to rescind).

Coverity issue: 302871
Fixes: 831dba47bd36 ("bus/vmbus: add Hyper-V virtual bus support")

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>

diff --git a/drivers/bus/vmbus/linux/vmbus_uio.c b/drivers/bus/vmbus/linux/vmbus_uio.c
index bc2c623..856c6d6 100644 (file)
--- a/drivers/bus/vmbus/linux/vmbus_uio.c
+++ b/drivers/bus/vmbus/linux/vmbus_uio.c
@@ -39,11 +39,17 @@ void vmbus_uio_irq_control(struct rte_vmbus_device *dev, int32_t onoff)
 int vmbus_uio_irq_read(struct rte_vmbus_device *dev)
 {
        int32_t count;
-
-       if (read(dev->intr_handle.fd, &count, sizeof(count)) < 0) {
-               VMBUS_LOG(ERR, "cannot read to %d:%s",
-                       dev->intr_handle.fd, strerror(errno));
-               count = -errno;
+       int cc;
+
+       cc = read(dev->intr_handle.fd, &count, sizeof(count));
+       if (cc < (int)sizeof(count)) {
+               if (cc < 0) {
+                       VMBUS_LOG(ERR, "IRQ read failed %s",
+                                 strerror(errno));
+                       return -errno;
+               }
+               VMBUS_LOG(ERR, "can't read IRQ count");
+               return -EINVAL;
        }
 
        return count;