From: Marc-André Lureau Date: Fri, 2 Jun 2017 08:15:19 +0000 (+0400) Subject: vhost-user-bridge: fix iov_restore_front() warning X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=277238f9f41e0a429a24b05c03f3010b35c3e9d0;p=people%2Fpauldu%2Fqemu.git vhost-user-bridge: fix iov_restore_front() warning CC tests/vhost-user-bridge.o /home/dgilbert/git/qemu-world3/tests/vhost-user-bridge.c:228:23: warning: variables 'front' and 'iov' used in loop condition not modified in loop body [-Wfor-loop-analysis] for (cur = front; front != iov; cur++) { ^~~~~ ~~~ 1 warning generated. Fix the loop, document the function, and fix some related assert(). In practice, the loop bug was harmless because the front sg buffer is enough to discard/restore the header size. Reported-by: Dr. David Alan Gilbert Signed-off-by: Marc-André Lureau Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin Reviewed-by: Dr. David Alan Gilbert Tested-by: Jens Freimann --- diff --git a/tests/vhost-user-bridge.c b/tests/vhost-user-bridge.c index 8618c20d53..1e5b5ca3da 100644 --- a/tests/vhost-user-bridge.c +++ b/tests/vhost-user-bridge.c @@ -220,12 +220,18 @@ vubr_handle_tx(VuDev *dev, int qidx) free(elem); } + +/* this function reverse the effect of iov_discard_front() it must be + * called with 'front' being the original struct iovec and 'bytes' + * being the number of bytes you shaved off + */ static void iov_restore_front(struct iovec *front, struct iovec *iov, size_t bytes) { struct iovec *cur; - for (cur = front; front != iov; cur++) { + for (cur = front; cur != iov; cur++) { + assert(bytes >= cur->iov_len); bytes -= cur->iov_len; } @@ -302,7 +308,8 @@ vubr_backend_recv_cb(int sock, void *ctx) } iov_from_buf(sg, elem->in_num, 0, &hdr, sizeof hdr); total += hdrlen; - assert(iov_discard_front(&sg, &num, hdrlen) == hdrlen); + ret = iov_discard_front(&sg, &num, hdrlen); + assert(ret == hdrlen); } struct msghdr msg = {