[dpdk-dev] [PATCH 3/3] vmbus: handle eof on irq read

[Stephen Hemminger <stephen@networkplumber.org>]

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>
---
 drivers/bus/vmbus/linux/vmbus_uio.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/drivers/bus/vmbus/linux/vmbus_uio.c b/drivers/bus/vmbus/linux/vmbus_uio.c
index bc2c6235e6bc..856c6d66785d 100644
--- 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;
-- 
2.18.0