From: Greg Kurz <groug@kaod.org> To: qemu-devel@nongnu.org Cc: "Daniel P . Berrangé" <berrange@redhat.com>, "Michael S. Tsirkin" <mst@redhat.com>, "Dr. David Alan Gilbert" <dgilbert@redhat.com>, "Greg Kurz" <groug@kaod.org>, virtio-fs@redhat.com, "Stefan Hajnoczi" <stefanha@redhat.com>, "Vivek Goyal" <vgoyal@redhat.com> Subject: [PATCH v2 6/7] vhost-user: Monitor slave channel in vhost_user_read() Date: Fri, 12 Mar 2021 10:22:11 +0100 [thread overview] Message-ID: <20210312092212.782255-7-groug@kaod.org> (raw) In-Reply-To: <20210312092212.782255-1-groug@kaod.org> Now that everything is in place, have the nested event loop to monitor the slave channel. The source in the main event loop is destroyed and recreated to ensure any pending even for the slave channel that was previously detected is purged. This guarantees that the main loop wont invoke slave_read() based on an event that was already handled by the nested loop. Signed-off-by: Greg Kurz <groug@kaod.org> --- v2: - also monitor G_IO_HUP (Stefan) - refactored the code a bit --- hw/virtio/vhost-user.c | 35 ++++++++++++++++++++++++++++++++--- 1 file changed, 32 insertions(+), 3 deletions(-) diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c index 00256fa318a6..ded0c1045309 100644 --- a/hw/virtio/vhost-user.c +++ b/hw/virtio/vhost-user.c @@ -345,6 +345,35 @@ end: return G_SOURCE_REMOVE; } +static gboolean slave_read(QIOChannel *ioc, GIOCondition condition, + gpointer opaque); + +/* + * This updates the read handler to use a new event loop context. + * Event sources are removed from the previous context : this ensures + * that events detected in the previous context are purged. They will + * be re-detected and processed in the new context. + */ +static void slave_update_read_handler(struct vhost_dev *dev, + GMainContext *ctxt) +{ + struct vhost_user *u = dev->opaque; + + if (!u->slave_ioc) { + return; + } + + if (u->slave_src) { + g_source_destroy(u->slave_src); + g_source_unref(u->slave_src); + } + + u->slave_src = qio_channel_add_watch_source(u->slave_ioc, + G_IO_IN | G_IO_HUP, + slave_read, dev, NULL, + ctxt); +} + static int vhost_user_read(struct vhost_dev *dev, VhostUserMsg *msg) { struct vhost_user *u = dev->opaque; @@ -366,6 +395,7 @@ static int vhost_user_read(struct vhost_dev *dev, VhostUserMsg *msg) * be prepared for re-entrancy. So we create a new one and switch chr * to use it. */ + slave_update_read_handler(dev, ctxt); qemu_chr_be_update_read_handlers(chr->chr, ctxt); qemu_chr_fe_add_watch(chr, G_IO_IN | G_IO_HUP, vhost_user_read_cb, &data); @@ -377,6 +407,7 @@ static int vhost_user_read(struct vhost_dev *dev, VhostUserMsg *msg) * context that have been processed by the nested loop are purged. */ qemu_chr_be_update_read_handlers(chr->chr, prev_ctxt); + slave_update_read_handler(dev, NULL); g_main_loop_unref(loop); g_main_context_unref(ctxt); @@ -1580,9 +1611,7 @@ static int vhost_setup_slave_channel(struct vhost_dev *dev) return -1; } u->slave_ioc = ioc; - u->slave_src = qio_channel_add_watch_source(u->slave_ioc, - G_IO_IN | G_IO_HUP, - slave_read, dev, NULL, NULL); + slave_update_read_handler(dev, NULL); if (reply_supported) { msg.hdr.flags |= VHOST_USER_NEED_REPLY_MASK; -- 2.26.2
WARNING: multiple messages have this Message-ID (diff)
From: Greg Kurz <groug@kaod.org> To: qemu-devel@nongnu.org Cc: "Daniel P . Berrangé" <berrange@redhat.com>, "Michael S. Tsirkin" <mst@redhat.com>, virtio-fs@redhat.com, "Vivek Goyal" <vgoyal@redhat.com> Subject: [Virtio-fs] [PATCH v2 6/7] vhost-user: Monitor slave channel in vhost_user_read() Date: Fri, 12 Mar 2021 10:22:11 +0100 [thread overview] Message-ID: <20210312092212.782255-7-groug@kaod.org> (raw) In-Reply-To: <20210312092212.782255-1-groug@kaod.org> Now that everything is in place, have the nested event loop to monitor the slave channel. The source in the main event loop is destroyed and recreated to ensure any pending even for the slave channel that was previously detected is purged. This guarantees that the main loop wont invoke slave_read() based on an event that was already handled by the nested loop. Signed-off-by: Greg Kurz <groug@kaod.org> --- v2: - also monitor G_IO_HUP (Stefan) - refactored the code a bit --- hw/virtio/vhost-user.c | 35 ++++++++++++++++++++++++++++++++--- 1 file changed, 32 insertions(+), 3 deletions(-) diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c index 00256fa318a6..ded0c1045309 100644 --- a/hw/virtio/vhost-user.c +++ b/hw/virtio/vhost-user.c @@ -345,6 +345,35 @@ end: return G_SOURCE_REMOVE; } +static gboolean slave_read(QIOChannel *ioc, GIOCondition condition, + gpointer opaque); + +/* + * This updates the read handler to use a new event loop context. + * Event sources are removed from the previous context : this ensures + * that events detected in the previous context are purged. They will + * be re-detected and processed in the new context. + */ +static void slave_update_read_handler(struct vhost_dev *dev, + GMainContext *ctxt) +{ + struct vhost_user *u = dev->opaque; + + if (!u->slave_ioc) { + return; + } + + if (u->slave_src) { + g_source_destroy(u->slave_src); + g_source_unref(u->slave_src); + } + + u->slave_src = qio_channel_add_watch_source(u->slave_ioc, + G_IO_IN | G_IO_HUP, + slave_read, dev, NULL, + ctxt); +} + static int vhost_user_read(struct vhost_dev *dev, VhostUserMsg *msg) { struct vhost_user *u = dev->opaque; @@ -366,6 +395,7 @@ static int vhost_user_read(struct vhost_dev *dev, VhostUserMsg *msg) * be prepared for re-entrancy. So we create a new one and switch chr * to use it. */ + slave_update_read_handler(dev, ctxt); qemu_chr_be_update_read_handlers(chr->chr, ctxt); qemu_chr_fe_add_watch(chr, G_IO_IN | G_IO_HUP, vhost_user_read_cb, &data); @@ -377,6 +407,7 @@ static int vhost_user_read(struct vhost_dev *dev, VhostUserMsg *msg) * context that have been processed by the nested loop are purged. */ qemu_chr_be_update_read_handlers(chr->chr, prev_ctxt); + slave_update_read_handler(dev, NULL); g_main_loop_unref(loop); g_main_context_unref(ctxt); @@ -1580,9 +1611,7 @@ static int vhost_setup_slave_channel(struct vhost_dev *dev) return -1; } u->slave_ioc = ioc; - u->slave_src = qio_channel_add_watch_source(u->slave_ioc, - G_IO_IN | G_IO_HUP, - slave_read, dev, NULL, NULL); + slave_update_read_handler(dev, NULL); if (reply_supported) { msg.hdr.flags |= VHOST_USER_NEED_REPLY_MASK; -- 2.26.2
next prev parent reply other threads:[~2021-03-12 9:36 UTC|newest] Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-03-12 9:22 [PATCH v2 0/7] virtiofsd: Avoid potential deadlocks Greg Kurz 2021-03-12 9:22 ` [Virtio-fs] " Greg Kurz 2021-03-12 9:22 ` [PATCH v2 1/7] vhost-user: Drop misleading EAGAIN checks in slave_read() Greg Kurz 2021-03-12 9:22 ` [Virtio-fs] " Greg Kurz 2021-03-15 10:34 ` Stefan Hajnoczi 2021-03-15 10:34 ` [Virtio-fs] " Stefan Hajnoczi 2021-03-12 9:22 ` [PATCH v2 2/7] vhost-user: Fix double-close on slave_read() error path Greg Kurz 2021-03-12 9:22 ` [Virtio-fs] " Greg Kurz 2021-03-15 10:36 ` Stefan Hajnoczi 2021-03-15 10:36 ` [Virtio-fs] " Stefan Hajnoczi 2021-03-12 9:22 ` [PATCH v2 3/7] vhost-user: Factor out duplicated slave_fd teardown code Greg Kurz 2021-03-12 9:22 ` [Virtio-fs] " Greg Kurz 2021-03-15 10:36 ` Stefan Hajnoczi 2021-03-15 10:36 ` [Virtio-fs] " Stefan Hajnoczi 2021-03-12 9:22 ` [PATCH v2 4/7] vhost-user: Convert slave channel to QIOChannelSocket Greg Kurz 2021-03-12 9:22 ` [Virtio-fs] " Greg Kurz 2021-03-15 10:37 ` Stefan Hajnoczi 2021-03-15 10:37 ` [Virtio-fs] " Stefan Hajnoczi 2021-03-12 9:22 ` [PATCH v2 5/7] vhost-user: Introduce nested event loop in vhost_user_read() Greg Kurz 2021-03-12 9:22 ` [Virtio-fs] " Greg Kurz 2021-03-15 10:38 ` Stefan Hajnoczi 2021-03-15 10:38 ` [Virtio-fs] " Stefan Hajnoczi 2021-03-12 9:22 ` Greg Kurz [this message] 2021-03-12 9:22 ` [Virtio-fs] [PATCH v2 6/7] vhost-user: Monitor slave channel " Greg Kurz 2021-03-15 12:20 ` Stefan Hajnoczi 2021-03-15 12:20 ` [Virtio-fs] " Stefan Hajnoczi 2021-03-12 9:22 ` [PATCH v2 7/7] virtiofsd: Release vu_dispatch_lock when stopping queue Greg Kurz 2021-03-12 9:22 ` [Virtio-fs] " Greg Kurz 2021-03-15 14:57 ` Dr. David Alan Gilbert 2021-03-15 14:57 ` [Virtio-fs] " Dr. David Alan Gilbert
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