[PATCH v2] tools/hv: terminate fcopy daemon if read from uio fails

[Olaf Hering <olaf@aepfle.de>]

Terminate endless loop in reading fails, to avoid flooding syslog.

This happens if the state of "Guest services" integration service
is changed from "enabled" to "disabled" at runtime in the VM
settings. In this case pread returns EIO.

Also handle an interrupted system call, and continue in this case.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
---
v2: update commit message

A more complete fix is to handle this properly in the kernel,
by making the file descriptor unavailable for further operations.

 tools/hv/hv_fcopy_uio_daemon.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/tools/hv/hv_fcopy_uio_daemon.c b/tools/hv/hv_fcopy_uio_daemon.c
index 7a00f3066a98..281fd95dc0d8 100644
--- a/tools/hv/hv_fcopy_uio_daemon.c
+++ b/tools/hv/hv_fcopy_uio_daemon.c
@@ -468,8 +468,10 @@ int main(int argc, char *argv[])
 		 */
 		ret = pread(fcopy_fd, &tmp, sizeof(int), 0);
 		if (ret < 0) {
+			if (errno == EINTR || errno == EAGAIN)
+				continue;
 			syslog(LOG_ERR, "pread failed: %s", strerror(errno));
-			continue;
+			goto close;
 		}
 
 		len = HV_RING_SIZE;