From patchwork Thu Sep 27 13:28:24 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luiz Capitulino X-Patchwork-Id: 187365 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id A343E2C00A4 for ; Thu, 27 Sep 2012 23:31:27 +1000 (EST) Received: from localhost ([::1]:39324 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1THEBZ-0003gV-S3 for incoming@patchwork.ozlabs.org; Thu, 27 Sep 2012 09:31:25 -0400 Received: from eggs.gnu.org ([208.118.235.92]:46547) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1THE8T-0005pA-GH for qemu-devel@nongnu.org; Thu, 27 Sep 2012 09:28:22 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1THE8N-0003Zk-Gl for qemu-devel@nongnu.org; Thu, 27 Sep 2012 09:28:13 -0400 Received: from mx1.redhat.com ([209.132.183.28]:14540) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1THE8N-0003ZM-8I for qemu-devel@nongnu.org; Thu, 27 Sep 2012 09:28:07 -0400 Received: from int-mx12.intmail.prod.int.phx2.redhat.com (int-mx12.intmail.prod.int.phx2.redhat.com [10.5.11.25]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id q8RDS6kV008281 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Thu, 27 Sep 2012 09:28:06 -0400 Received: from localhost (ovpn-113-87.phx2.redhat.com [10.3.113.87]) by int-mx12.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id q8RDS5Vx015116; Thu, 27 Sep 2012 09:28:06 -0400 From: Luiz Capitulino To: aliguori@us.ibm.com Date: Thu, 27 Sep 2012 10:28:24 -0300 Message-Id: <1348752509-1142-11-git-send-email-lcapitulino@redhat.com> In-Reply-To: <1348752509-1142-1-git-send-email-lcapitulino@redhat.com> References: <1348752509-1142-1-git-send-email-lcapitulino@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.25 X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 209.132.183.28 Cc: qemu-devel@nongnu.org Subject: [Qemu-devel] [PULL 10/15] qmp: dump-guest-memory: don't spin if non-blocking fd would block X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org fd_write_vmcore() will indefinitely spin for a non-blocking file-descriptor that would block. However, if the fd is non-blocking, how does it make sense to spin? Change this behavior to return an error instead. Note that this can only happen with an fd provided by a management application. The fd opened internally by dump-guest-memory is blocking. While there, also fix 'writen_size' variable name. Signed-off-by: Luiz Capitulino Reviewed-by: Eric Blake Reviewed-by: Markus Armbruster --- dump.c | 15 ++++----------- 1 file changed, 4 insertions(+), 11 deletions(-) diff --git a/dump.c b/dump.c index 1a3c716..6b7c127 100644 --- a/dump.c +++ b/dump.c @@ -100,18 +100,11 @@ static void dump_error(DumpState *s, const char *reason) static int fd_write_vmcore(void *buf, size_t size, void *opaque) { DumpState *s = opaque; - int fd = s->fd; - size_t writen_size; + size_t written_size; - /* The fd may be passed from user, and it can be non-blocked */ - while (size) { - writen_size = qemu_write_full(fd, buf, size); - if (writen_size != size && errno != EAGAIN) { - return -1; - } - - buf += writen_size; - size -= writen_size; + written_size = qemu_write_full(s->fd, buf, size); + if (written_size != size) { + return -1; } return 0;