From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51986) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZsRu5-0005CD-Cd for qemu-devel@nongnu.org; Sat, 31 Oct 2015 04:52:50 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZsRu2-0006cm-6S for qemu-devel@nongnu.org; Sat, 31 Oct 2015 04:52:49 -0400 Received: from mga01.intel.com ([192.55.52.88]:59665) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZsRu2-0006cY-0y for qemu-devel@nongnu.org; Sat, 31 Oct 2015 04:52:46 -0400 References: <1446184587-142784-1-git-send-email-guangrong.xiao@linux.intel.com> <1446184587-142784-12-git-send-email-guangrong.xiao@linux.intel.com> <20151030173042.GC7865@thinpad.lan.raisama.net> From: Xiao Guangrong Message-ID: <56347FCD.7080609@linux.intel.com> Date: Sat, 31 Oct 2015 16:46:05 +0800 MIME-Version: 1.0 In-Reply-To: <20151030173042.GC7865@thinpad.lan.raisama.net> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v6 11/33] hostmem-file: use whole file size if possible List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Eduardo Habkost Cc: kvm@vger.kernel.org, mst@redhat.com, gleb@kernel.org, mtosatti@redhat.com, qemu-devel@nongnu.org, stefanha@redhat.com, imammedo@redhat.com, pbonzini@redhat.com, dan.j.williams@intel.com, rth@twiddle.net On 10/31/2015 01:30 AM, Eduardo Habkost wrote: > On Fri, Oct 30, 2015 at 01:56:05PM +0800, Xiao Guangrong wrote: >> Use the whole file size if @size is not specified which is useful >> if we want to directly pass a file to guest >> >> Signed-off-by: Xiao Guangrong >> --- >> backends/hostmem-file.c | 48 ++++++++++++++++++++++++++++++++++++++++++++---- >> 1 file changed, 44 insertions(+), 4 deletions(-) >> >> diff --git a/backends/hostmem-file.c b/backends/hostmem-file.c >> index 9097a57..e1bc9ff 100644 >> --- a/backends/hostmem-file.c >> +++ b/backends/hostmem-file.c >> @@ -9,6 +9,9 @@ >> * This work is licensed under the terms of the GNU GPL, version 2 or later. >> * See the COPYING file in the top-level directory. >> */ >> +#include >> +#include > > This code needs to build on other platforms too. e.g. using mingw32: Err... You did it on Windows? It's surprised that the file is only built on Linux: common-obj-$(CONFIG_LINUX) += hostmem-file.o How it can happen... > > CC backends/hostmem-file.o > /home/ehabkost/rh/proj/virt/qemu/backends/hostmem-file.c:12:23: fatal error: sys/ioctl.h: No such file or directory > #include > ^ > compilation terminated. > /home/ehabkost/rh/proj/virt/qemu/rules.mak:57: recipe for target 'backends/hostmem-file.o' failed > make: *** [backends/hostmem-file.o] Error 1 > > >> + >> #include "qemu-common.h" >> #include "sysemu/hostmem.h" >> #include "sysemu/sysemu.h" >> @@ -33,20 +36,57 @@ struct HostMemoryBackendFile { >> char *mem_path; >> }; >> >> +static uint64_t get_file_size(const char *file) >> +{ >> + struct stat stat_buf; >> + uint64_t size = 0; >> + int fd; >> + >> + fd = open(file, O_RDONLY); >> + if (fd < 0) { >> + return 0; >> + } >> + >> + if (stat(file, &stat_buf) < 0) { >> + goto exit; >> + } >> + >> + if ((S_ISBLK(stat_buf.st_mode)) && !ioctl(fd, BLKGETSIZE64, &size)) { >> + goto exit; >> + } >> + >> + size = lseek(fd, 0, SEEK_END); >> + if (size == -1) { >> + size = 0; >> + } >> +exit: >> + close(fd); >> + return size; >> +} > > This code seems to duplicate what block/raw-posix.c:raw_getlength() does > (except for the BLKGETSIZE64 part). Have you considered using the same > code for both? > > We can probably move all the raw-posix.c raw_getlength(BlockDriverState > *bs) code to fd_getlength(int fd) functions (on osdep.c?), and just > implement raw-posix.c:raw_getlength(s) as fd_getlength(s->fd). > Actually, Paolo has the same suggestion before... but | The function you pointed out is really complex - it mixed 9 platforms and each | platform has its own specific implementation. It is hard for us to verify the | change. | | I'd prefer to make it for Linux specific first then share it to other platforms | if it's needed in the future. I do not know if it's really worth doing it. :(