From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47547) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZeODV-00047z-Nj for qemu-devel@nongnu.org; Tue, 22 Sep 2015 10:06:50 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZeODT-0004hl-25 for qemu-devel@nongnu.org; Tue, 22 Sep 2015 10:06:45 -0400 Received: from lhrrgout.huawei.com ([194.213.3.17]:22999) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZeODS-0004cm-Js for qemu-devel@nongnu.org; Tue, 22 Sep 2015 10:06:42 -0400 References: <1442333283-13119-1-git-send-email-marcandre.lureau@redhat.com> <1442333283-13119-7-git-send-email-marcandre.lureau@redhat.com> From: Claudio Fontana Message-ID: <5601606B.1040709@huawei.com> Date: Tue, 22 Sep 2015 16:06:35 +0200 MIME-Version: 1.0 In-Reply-To: <1442333283-13119-7-git-send-email-marcandre.lureau@redhat.com> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Subject: Re: [Qemu-devel] [PATCH v3 06/46] ivshmem: remove unnecessary dup() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: marcandre.lureau@redhat.com, qemu-devel@nongnu.org Cc: drjones@redhat.com, cam@cs.ualberta.ca, stefanha@redhat.com On 15.09.2015 18:07, marcandre.lureau@redhat.com wrote: > From: Marc-André Lureau > > qemu_chr_fe_get_msgfd() transfers ownership, there is no need to dup the > fd. > Are you sure? (tested?) There is a specific comment that the dup is done because of the get_msgfds implementation, I checked tcp_get_msgfds and it closes unused fds, is this ok? static int tcp_get_msgfds(...) { ... /* Close unused fds */ for (i = to_copy, i < s->read_msgfds_num; i++) { close(s->read_msgfds[i]); } ... > Signed-off-by: Marc-André Lureau > --- > hw/misc/ivshmem.c | 21 ++++++--------------- > 1 file changed, 6 insertions(+), 15 deletions(-) > > diff --git a/hw/misc/ivshmem.c b/hw/misc/ivshmem.c > index dd15f0e..fbeb731 100644 > --- a/hw/misc/ivshmem.c > +++ b/hw/misc/ivshmem.c > @@ -480,7 +480,7 @@ static bool fifo_update_and_get(IVShmemState *s, const uint8_t *buf, int size, > static void ivshmem_read(void *opaque, const uint8_t *buf, int size) > { > IVShmemState *s = opaque; > - int incoming_fd, tmp_fd; > + int incoming_fd; > int guest_max_eventfd; > long incoming_posn; > > @@ -495,21 +495,21 @@ static void ivshmem_read(void *opaque, const uint8_t *buf, int size) > } > > /* pick off s->server_chr->msgfd and store it, posn should accompany msg */ > - tmp_fd = qemu_chr_fe_get_msgfd(s->server_chr); > - IVSHMEM_DPRINTF("posn is %ld, fd is %d\n", incoming_posn, tmp_fd); > + incoming_fd = qemu_chr_fe_get_msgfd(s->server_chr); > + IVSHMEM_DPRINTF("posn is %ld, fd is %d\n", incoming_posn, incoming_fd); > > /* make sure we have enough space for this guest */ > if (incoming_posn >= s->nb_peers) { > if (increase_dynamic_storage(s, incoming_posn) < 0) { > error_report("increase_dynamic_storage() failed"); > - if (tmp_fd != -1) { > - close(tmp_fd); > + if (incoming_fd != -1) { > + close(incoming_fd); > } > return; > } > } > > - if (tmp_fd == -1) { > + if (incoming_fd == -1) { > /* if posn is positive and unseen before then this is our posn*/ > if ((incoming_posn >= 0) && > (s->peers[incoming_posn].eventfds == NULL)) { > @@ -524,15 +524,6 @@ static void ivshmem_read(void *opaque, const uint8_t *buf, int size) > } > } > > - /* because of the implementation of get_msgfd, we need a dup */ > - incoming_fd = dup(tmp_fd); > - > - if (incoming_fd == -1) { > - error_report("could not allocate file descriptor %s", strerror(errno)); > - close(tmp_fd); > - return; > - } > - > /* if the position is -1, then it's shared memory region fd */ > if (incoming_posn == -1) { > >