From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38906) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dI8pM-0000nD-Ub for qemu-devel@nongnu.org; Tue, 06 Jun 2017 03:22:59 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dI8pL-0005NA-Se for qemu-devel@nongnu.org; Tue, 06 Jun 2017 03:22:56 -0400 Received: from mga03.intel.com ([134.134.136.65]:58638) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dI8pL-0005K6-Jx for qemu-devel@nongnu.org; Tue, 06 Jun 2017 03:22:55 -0400 From: Haozhong Zhang Date: Tue, 6 Jun 2017 15:22:29 +0800 Message-Id: <20170606072229.9302-5-haozhong.zhang@intel.com> In-Reply-To: <20170606072229.9302-1-haozhong.zhang@intel.com> References: <20170606072229.9302-1-haozhong.zhang@intel.com> Subject: [Qemu-devel] [PATCH v2 4/4] util/mmap-alloc: account for DAX device in qemu_fd_getpagesize List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: "Michael S. Tsirkin" , Igor Mammedov , Xiao Guangrong , Stefan Hajnoczi , Dan Williams , Haozhong Zhang A DAX device may require a page size different than getpagesize(). Signed-off-by: Haozhong Zhang --- include/qemu/osdep.h | 10 ++++++++++ util/mmap-alloc.c | 6 ++++++ util/osdep.c | 23 +++++++++++++++++++++++ 3 files changed, 39 insertions(+) diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h index 7f26af371e..51aca88f0d 100644 --- a/include/qemu/osdep.h +++ b/include/qemu/osdep.h @@ -479,4 +479,14 @@ pid_t qemu_fork(Error **errp); */ bool qemu_fd_is_dev_dax(int fd); +/** + * qemu_get_dev_dax_align: + * + * Get the suggested alignment of a DAX device descried by @fd. + * + * Return a non-zero suggested alignment on success; return 0 if @fd + * does not describe a DAX device, or if it fails to get alignment + * of the DAX device. + */ +size_t qemu_get_dev_dax_align(int fd); #endif diff --git a/util/mmap-alloc.c b/util/mmap-alloc.c index 3ec029a9ea..2d8af64b44 100644 --- a/util/mmap-alloc.c +++ b/util/mmap-alloc.c @@ -25,8 +25,14 @@ size_t qemu_fd_getpagesize(int fd) #ifdef CONFIG_LINUX struct statfs fs; int ret; + size_t align; if (fd != -1) { + align = qemu_get_dev_dax_align(fd); + if (align) { + return align; + } + do { ret = fstatfs(fd, &fs); } while (ret != 0 && errno == EINTR); diff --git a/util/osdep.c b/util/osdep.c index 02881f96bc..e7837d30b4 100644 --- a/util/osdep.c +++ b/util/osdep.c @@ -532,3 +532,26 @@ bool qemu_fd_is_dev_dax(int fd) return is_dax; } + +size_t qemu_get_dev_dax_align(int fd) +{ + size_t align = 0; + +#ifdef __linux__ + char buf[12]; + ssize_t len; + + if (!qemu_fd_is_dev_dax(fd)) { + return 0; + } + len = qemu_dev_dax_sysfs_read(fd, "device/align", buf, sizeof(buf)); + if (len <= 0) { + return 0; + } + if (qemu_strtosz(buf, NULL, &align) < 0) { + align = 0; + } +#endif /* __linux__ */ + + return align; +} -- 2.11.0