From patchwork Mon Nov 2 09:13:11 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Xiao Guangrong X-Patchwork-Id: 7534911 Return-Path: X-Original-To: patchwork-kvm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 6103E9F327 for ; Mon, 2 Nov 2015 09:20:17 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 7FDAC20591 for ; Mon, 2 Nov 2015 09:20:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7DD91205DD for ; Mon, 2 Nov 2015 09:20:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751633AbbKBJUM (ORCPT ); Mon, 2 Nov 2015 04:20:12 -0500 Received: from mga01.intel.com ([192.55.52.88]:15660 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753474AbbKBJUC (ORCPT ); Mon, 2 Nov 2015 04:20:02 -0500 Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga101.fm.intel.com with ESMTP; 02 Nov 2015 01:19:42 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.20,234,1444719600"; d="scan'208";a="840963103" Received: from xiaoreal1.sh.intel.com (HELO xiaoreal1.sh.intel.com.sh.intel.com) ([10.239.48.79]) by fmsmga002.fm.intel.com with ESMTP; 02 Nov 2015 01:19:23 -0800 From: Xiao Guangrong To: pbonzini@redhat.com, imammedo@redhat.com Cc: gleb@kernel.org, mtosatti@redhat.com, stefanha@redhat.com, mst@redhat.com, rth@twiddle.net, ehabkost@redhat.com, dan.j.williams@intel.com, kvm@vger.kernel.org, qemu-devel@nongnu.org, vsementsov@virtuozzo.com, eblake@redhat.com, Xiao Guangrong Subject: [PATCH v7 09/35] exec: allow file_ram_alloc to work on file Date: Mon, 2 Nov 2015 17:13:11 +0800 Message-Id: <1446455617-129562-10-git-send-email-guangrong.xiao@linux.intel.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1446455617-129562-1-git-send-email-guangrong.xiao@linux.intel.com> References: <1446455617-129562-1-git-send-email-guangrong.xiao@linux.intel.com> Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Currently, file_ram_alloc() only works on directory - it creates a file under @path and do mmap on it This patch tries to allow it to work on file directly, if @path is a directory it works as before, otherwise it treats @path as the target file then directly allocate memory from it Signed-off-by: Xiao Guangrong Reviewed-by: Vladimir Sementsov-Ogievskiy --- exec.c | 80 ++++++++++++++++++++++++++++++++++++++++++------------------------ 1 file changed, 51 insertions(+), 29 deletions(-) diff --git a/exec.c b/exec.c index 9075f4d..db0fdaf 100644 --- a/exec.c +++ b/exec.c @@ -1174,14 +1174,60 @@ void qemu_mutex_unlock_ramlist(void) } #ifdef __linux__ +static bool path_is_dir(const char *path) +{ + struct stat fs; + + return stat(path, &fs) == 0 && S_ISDIR(fs.st_mode); +} + +static int open_ram_file_path(RAMBlock *block, const char *path, size_t size) +{ + char *filename; + char *sanitized_name; + char *c; + int fd; + + if (!path_is_dir(path)) { + int flags = (block->flags & RAM_SHARED) ? O_RDWR : O_RDONLY; + + flags |= O_EXCL; + return open(path, flags); + } + + /* Make name safe to use with mkstemp by replacing '/' with '_'. */ + sanitized_name = g_strdup(memory_region_name(block->mr)); + for (c = sanitized_name; *c != '\0'; c++) { + if (*c == '/') { + *c = '_'; + } + } + filename = g_strdup_printf("%s/qemu_back_mem.%s.XXXXXX", path, + sanitized_name); + g_free(sanitized_name); + fd = mkstemp(filename); + if (fd >= 0) { + unlink(filename); + /* + * ftruncate is not supported by hugetlbfs in older + * hosts, so don't bother bailing out on errors. + * If anything goes wrong with it under other filesystems, + * mmap will fail. + */ + if (ftruncate(fd, size)) { + perror("ftruncate"); + } + } + g_free(filename); + + return fd; +} + static void *file_ram_alloc(RAMBlock *block, ram_addr_t memory, const char *path, Error **errp) { - char *filename; - char *sanitized_name; - char *c; void *area; int fd; uint64_t pagesize; @@ -1212,38 +1258,14 @@ static void *file_ram_alloc(RAMBlock *block, goto error; } - /* Make name safe to use with mkstemp by replacing '/' with '_'. */ - sanitized_name = g_strdup(memory_region_name(block->mr)); - for (c = sanitized_name; *c != '\0'; c++) { - if (*c == '/') - *c = '_'; - } - - filename = g_strdup_printf("%s/qemu_back_mem.%s.XXXXXX", path, - sanitized_name); - g_free(sanitized_name); + memory = ROUND_UP(memory, pagesize); - fd = mkstemp(filename); + fd = open_ram_file_path(block, path, memory); if (fd < 0) { error_setg_errno(errp, errno, "unable to create backing store for path %s", path); - g_free(filename); goto error; } - unlink(filename); - g_free(filename); - - memory = ROUND_UP(memory, pagesize); - - /* - * ftruncate is not supported by hugetlbfs in older - * hosts, so don't bother bailing out on errors. - * If anything goes wrong with it under other filesystems, - * mmap will fail. - */ - if (ftruncate(fd, memory)) { - perror("ftruncate"); - } area = qemu_ram_mmap(fd, memory, pagesize, block->flags & RAM_SHARED); if (area == MAP_FAILED) {