From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40338) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aQePS-00038g-E3 for qemu-devel@nongnu.org; Tue, 02 Feb 2016 12:06:35 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aQePN-0001KO-Au for qemu-devel@nongnu.org; Tue, 02 Feb 2016 12:06:34 -0500 Received: from mx1.redhat.com ([209.132.183.28]:54798) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aQePN-0001KH-0c for qemu-devel@nongnu.org; Tue, 02 Feb 2016 12:06:29 -0500 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (Postfix) with ESMTPS id 4ADE4804FF for ; Tue, 2 Feb 2016 17:06:28 +0000 (UTC) Date: Tue, 2 Feb 2016 17:06:24 +0000 From: "Dr. David Alan Gilbert" Message-ID: <20160202170623.GA4498@work-vm> References: <1452599056-27357-1-git-send-email-berrange@redhat.com> <1452599056-27357-8-git-send-email-berrange@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1452599056-27357-8-git-send-email-berrange@redhat.com> Subject: Re: [Qemu-devel] [PATCH v1 07/22] migration: introduce a new QEMUFile impl based on QIOChannel List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Daniel P. Berrange" Cc: Amit Shah , qemu-devel@nongnu.org, Juan Quintela * Daniel P. Berrange (berrange@redhat.com) wrote: > Introduce a new QEMUFile implementation that is based on > the QIOChannel objects. This impl is different from existing > impls in that there is no file descriptor that can be made > available, as some channels may be based on higher level > protocols such as TLS. > > Although the QIOChannel based implementation can trivially > provide a bi-directional stream, initially we have separate > functions for opening input & output directions to fit with > the expectation of the current QEMUFile interface. > > Signed-off-by: Daniel P. Berrange > --- > include/migration/qemu-file.h | 4 + > migration/Makefile.objs | 1 + > migration/qemu-file-channel.c | 201 ++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 206 insertions(+) > create mode 100644 migration/qemu-file-channel.c > > diff --git a/include/migration/qemu-file.h b/include/migration/qemu-file.h > index 072bb38..cb79311 100644 > --- a/include/migration/qemu-file.h > +++ b/include/migration/qemu-file.h > @@ -23,7 +23,9 @@ > */ > #ifndef QEMU_FILE_H > #define QEMU_FILE_H 1 > +#include "qemu-common.h" > #include "exec/cpu-common.h" > +#include "io/channel.h" > > #include > > @@ -136,6 +138,8 @@ QEMUFile *qemu_fopen_ops(void *opaque, const QEMUFileOps *ops); > QEMUFile *qemu_fopen(const char *filename, const char *mode); > QEMUFile *qemu_fdopen(int fd, const char *mode); > QEMUFile *qemu_fopen_socket(int fd, const char *mode); > +QEMUFile *qemu_fopen_channel_input(QIOChannel *ioc); > +QEMUFile *qemu_fopen_channel_output(QIOChannel *ioc); > QEMUFile *qemu_popen_cmd(const char *command, const char *mode); > QEMUFile *qemu_bufopen(const char *mode, QEMUSizedBuffer *input); > void qemu_file_set_hooks(QEMUFile *f, const QEMUFileHooks *hooks); > diff --git a/migration/Makefile.objs b/migration/Makefile.objs > index 0cac6d7..b357e2f 100644 > --- a/migration/Makefile.objs > +++ b/migration/Makefile.objs > @@ -1,6 +1,7 @@ > common-obj-y += migration.o tcp.o > common-obj-y += vmstate.o > common-obj-y += qemu-file.o qemu-file-buf.o qemu-file-unix.o qemu-file-stdio.o > +common-obj-y += qemu-file-channel.o > common-obj-y += xbzrle.o postcopy-ram.o > > common-obj-$(CONFIG_RDMA) += rdma.o > diff --git a/migration/qemu-file-channel.c b/migration/qemu-file-channel.c > new file mode 100644 > index 0000000..09a7170 > --- /dev/null > +++ b/migration/qemu-file-channel.c > @@ -0,0 +1,201 @@ > +/* > + * QEMUFile backend for QIOChannel objects > + * > + * Copyright (c) 2015 Red Hat, Inc > + * > + * Permission is hereby granted, free of charge, to any person obtaining a copy > + * of this software and associated documentation files (the "Software"), to deal > + * in the Software without restriction, including without limitation the rights > + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell > + * copies of the Software, and to permit persons to whom the Software is > + * furnished to do so, subject to the following conditions: > + * > + * The above copyright notice and this permission notice shall be included in > + * all copies or substantial portions of the Software. > + * > + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR > + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, > + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL > + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER > + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, > + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN > + * THE SOFTWARE. > + */ > +#include "migration/qemu-file.h" > +#include "io/channel-socket.h" > +#include "qemu/iov.h" > + > + > +/** > + * @skip: number of bytes to advance head of @iov > + * @iov: pointer to iov array, updated on success > + * @iovcnt: number of elements in @iov, updated on success > + * @oldiov: pointer single element to hold old info from @iov > + * > + * This will update @iov so that its head is advanced > + * by @skip bytes. To do this, zero or more complete > + * elements of @iov will be skipped over. The new head > + * of @iov will then have its base & len updated to > + * skip the remaining number of bytes. @oldiov will > + * hold the original data from the new head of @iov. > + */ > +static void channel_skip_iov(size_t skip, > + struct iovec **iov, > + int *iovcnt, > + struct iovec *oldiov) > +{ > + ssize_t done = 0; > + size_t i; > + for (i = 0; i < *iovcnt; i++) { > + if ((*iov)[i].iov_len <= skip) { > + done += (*iov)[i].iov_len; > + skip -= (*iov)[i].iov_len; > + } else { > + done += skip; > + oldiov->iov_base = (*iov)[i].iov_base; > + oldiov->iov_len = (*iov)[i].iov_len; > + (*iov)[i].iov_len -= skip; > + (*iov)[i].iov_base += skip; > + *iov = *iov + i; > + *iovcnt = *iovcnt - i; > + break; > + } > + } > +} > + > +static ssize_t channel_writev_buffer(void *opaque, > + struct iovec *iov, > + int iovcnt, > + int64_t pos) > +{ > + QIOChannel *ioc = QIO_CHANNEL(opaque); > + ssize_t done = 0; > + ssize_t want = iov_size(iov, iovcnt); > + struct iovec oldiov = { NULL, 0 }; > + > + while (done < want) { > + ssize_t len; > + struct iovec *cur = iov; > + int curcnt = iovcnt; > + > + channel_skip_iov(done, &cur, &curcnt, &oldiov); > + > + len = qio_channel_writev(ioc, cur, curcnt, NULL); > + if (oldiov.iov_base) { > + /* Restore original caller's info in @iov */ > + cur[0].iov_base = oldiov.iov_base; > + cur[0].iov_len = oldiov.iov_len; > + oldiov.iov_base = NULL; > + oldiov.iov_len = 0; > + } > + if (len == QIO_CHANNEL_ERR_BLOCK) { > + qio_channel_wait(ioc, G_IO_OUT); > + continue; > + } > + if (len < 0) { > + /* XXX handle Error objects */ > + return -EIO; It's best to return 'len' rather than lose what little error information you had (similarly below). > + } > + > + done += len; > + } > + return done; > +} > + > + > +static ssize_t channel_get_buffer(void *opaque, > + uint8_t *buf, > + int64_t pos, > + size_t size) > +{ > + QIOChannel *ioc = QIO_CHANNEL(opaque); > + ssize_t ret; > + > + reread: > + ret = qio_channel_read(ioc, (char *)buf, size, NULL); > + if (ret < 0) { > + if (ret == QIO_CHANNEL_ERR_BLOCK) { > + qio_channel_yield(ioc, G_IO_IN); > + goto reread; > + } else { > + /* XXX handle Error * object */ > + return -EIO; > + } > + } > + return ret; I'd prefer a loop to a goto; generally the only places we use goto is an error exit. do { ret = qio_channel_read(ioc, (char *)buf, size, NULL); if (ret == QIO_CHANNEL_ERR_BLOCK) { qio_channel_yield(ioc, G_IO_IN); } } while (ret == QIO_CHANNEL_ERR_BLOCK); return ret; and IMHO the loop is clearer. > +} > + > + > +static int channel_close(void *opaque) > +{ > + QIOChannel *ioc = QIO_CHANNEL(opaque); > + qio_channel_close(ioc, NULL); > + object_unref(OBJECT(ioc)); > + return 0; > +} > + > + > +static int channel_shutdown(void *opaque, > + bool rd, > + bool wr) > +{ > + QIOChannel *ioc = QIO_CHANNEL(opaque); > + > + if (qio_channel_has_feature(ioc, > + QIO_CHANNEL_FEATURE_SHUTDOWN)) { > + QIOChannelShutdown mode; > + if (rd && wr) { > + mode = QIO_CHANNEL_SHUTDOWN_BOTH; > + } else if (rd) { > + mode = QIO_CHANNEL_SHUTDOWN_READ; > + } else { > + mode = QIO_CHANNEL_SHUTDOWN_WRITE; > + } > + if (qio_channel_shutdown(ioc, mode, NULL) < 0) { > + /* XXX handler Error * object */ > + return -EIO; > + } > + } > + return 0; > +} > + > + > +static int channel_set_blocking(void *opaque, > + bool enabled) > +{ > + QIOChannel *ioc = QIO_CHANNEL(opaque); > + > + if (qio_channel_set_blocking(ioc, enabled, NULL) < 0) { > + return -1; > + } > + return 0; > +} > + > + > +static const QEMUFileOps channel_input_ops = { > + .get_buffer = channel_get_buffer, > + .close = channel_close, > + .shut_down = channel_shutdown, > + .set_blocking = channel_set_blocking, > +}; > + > + > +static const QEMUFileOps channel_output_ops = { > + .writev_buffer = channel_writev_buffer, > + .close = channel_close, > + .shut_down = channel_shutdown, > + .set_blocking = channel_set_blocking, > +}; > + > + > +QEMUFile *qemu_fopen_channel_input(QIOChannel *ioc) > +{ > + object_ref(OBJECT(ioc)); > + return qemu_fopen_ops(ioc, &channel_input_ops); > +} > + > +QEMUFile *qemu_fopen_channel_output(QIOChannel *ioc) > +{ > + object_ref(OBJECT(ioc)); > + return qemu_fopen_ops(ioc, &channel_output_ops); > +} Dave > -- > 2.5.0 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK