From 803ca43e4c7fcf32f9f68c118301ccd0c83ece3f Mon Sep 17 00:00:00 2001 From: Leonardo Bras Date: Mon, 20 Jun 2022 02:39:42 -0300 Subject: QIOChannelSocket: Introduce assert and reduce ifdefs to improve readability MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit During implementation of MSG_ZEROCOPY feature, a lot of #ifdefs were introduced, particularly at qio_channel_socket_writev(). Rewrite some of those changes so it's easier to read. Also, introduce an assert to help detect incorrect zero-copy usage is when it's disabled on build. Signed-off-by: Leonardo Bras Reviewed-by: Daniel P. Berrangé Reviewed-by: Juan Quintela Reviewed-by: Peter Xu Signed-off-by: Juan Quintela Signed-off-by: Dr. David Alan Gilbert dgilbert: Fixed up thinko'd g_assert_unreachable->g_assert_not_reached --- io/channel-socket.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) (limited to 'io/channel-socket.c') diff --git a/io/channel-socket.c b/io/channel-socket.c index dc9c165de1..b8c13dba7c 100644 --- a/io/channel-socket.c +++ b/io/channel-socket.c @@ -578,11 +578,17 @@ static ssize_t qio_channel_socket_writev(QIOChannel *ioc, memcpy(CMSG_DATA(cmsg), fds, fdsize); } -#ifdef QEMU_MSG_ZEROCOPY if (flags & QIO_CHANNEL_WRITE_FLAG_ZERO_COPY) { +#ifdef QEMU_MSG_ZEROCOPY sflags = MSG_ZEROCOPY; - } +#else + /* + * We expect QIOChannel class entry point to have + * blocked this code path already + */ + g_assert_not_reached(); #endif + } retry: ret = sendmsg(sioc->fd, &msg, sflags); @@ -592,15 +598,13 @@ static ssize_t qio_channel_socket_writev(QIOChannel *ioc, return QIO_CHANNEL_ERR_BLOCK; case EINTR: goto retry; -#ifdef QEMU_MSG_ZEROCOPY case ENOBUFS: - if (sflags & MSG_ZEROCOPY) { + if (flags & QIO_CHANNEL_WRITE_FLAG_ZERO_COPY) { error_setg_errno(errp, errno, "Process can't lock enough memory for using MSG_ZEROCOPY"); return -1; } break; -#endif } error_setg_errno(errp, errno, -- cgit v1.2.3 From 4f5a09714c983a3471fd12e3c7f3196e95c650c1 Mon Sep 17 00:00:00 2001 From: Leonardo Bras Date: Mon, 20 Jun 2022 02:39:43 -0300 Subject: QIOChannelSocket: Fix zero-copy send so socket flush works MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Somewhere between v6 and v7 the of the zero-copy-send patchset a crucial part of the flushing mechanism got missing: incrementing zero_copy_queued. Without that, the flushing interface becomes a no-op, and there is no guarantee the buffer is really sent. This can go as bad as causing a corruption in RAM during migration. Fixes: 2bc58ffc2926 ("QIOChannelSocket: Implement io_writev zero copy flag & io_flush for CONFIG_LINUX") Reported-by: 徐闯 Signed-off-by: Leonardo Bras Reviewed-by: Daniel P. Berrangé Reviewed-by: Peter Xu Reviewed-by: Juan Quintela Signed-off-by: Juan Quintela Signed-off-by: Dr. David Alan Gilbert --- io/channel-socket.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'io/channel-socket.c') diff --git a/io/channel-socket.c b/io/channel-socket.c index b8c13dba7c..4466bb1cd4 100644 --- a/io/channel-socket.c +++ b/io/channel-socket.c @@ -611,6 +611,11 @@ static ssize_t qio_channel_socket_writev(QIOChannel *ioc, "Unable to write to socket"); return -1; } + + if (flags & QIO_CHANNEL_WRITE_FLAG_ZERO_COPY) { + sioc->zero_copy_queued++; + } + return ret; } #else /* WIN32 */ -- cgit v1.2.3