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[PULL 068/111] contrib/libvhost-user: Protect slave fd with mutex
From: |
Dr. David Alan Gilbert (git) |
Subject: |
[PULL 068/111] contrib/libvhost-user: Protect slave fd with mutex |
Date: |
Thu, 23 Jan 2020 11:57:58 +0000 |
From: "Dr. David Alan Gilbert" <address@hidden>
In future patches we'll be performing commands on the slave-fd driven
by commands on queues, since those queues will be driven by individual
threads we need to make sure they don't attempt to use the slave-fd
for multiple commands in parallel.
Signed-off-by: Dr. David Alan Gilbert <address@hidden>
Reviewed-by: Daniel P. Berrangé <address@hidden>
Signed-off-by: Dr. David Alan Gilbert <address@hidden>
---
contrib/libvhost-user/libvhost-user.c | 24 ++++++++++++++++++++----
contrib/libvhost-user/libvhost-user.h | 3 +++
2 files changed, 23 insertions(+), 4 deletions(-)
diff --git a/contrib/libvhost-user/libvhost-user.c
b/contrib/libvhost-user/libvhost-user.c
index ec27b78ff1..63e41062a4 100644
--- a/contrib/libvhost-user/libvhost-user.c
+++ b/contrib/libvhost-user/libvhost-user.c
@@ -392,26 +392,37 @@ vu_send_reply(VuDev *dev, int conn_fd, VhostUserMsg *vmsg)
return vu_message_write(dev, conn_fd, vmsg);
}
+/*
+ * Processes a reply on the slave channel.
+ * Entered with slave_mutex held and releases it before exit.
+ * Returns true on success.
+ */
static bool
vu_process_message_reply(VuDev *dev, const VhostUserMsg *vmsg)
{
VhostUserMsg msg_reply;
+ bool result = false;
if ((vmsg->flags & VHOST_USER_NEED_REPLY_MASK) == 0) {
- return true;
+ result = true;
+ goto out;
}
if (!vu_message_read(dev, dev->slave_fd, &msg_reply)) {
- return false;
+ goto out;
}
if (msg_reply.request != vmsg->request) {
DPRINT("Received unexpected msg type. Expected %d received %d",
vmsg->request, msg_reply.request);
- return false;
+ goto out;
}
- return msg_reply.payload.u64 == 0;
+ result = msg_reply.payload.u64 == 0;
+
+out:
+ pthread_mutex_unlock(&dev->slave_mutex);
+ return result;
}
/* Kick the log_call_fd if required. */
@@ -1105,10 +1116,13 @@ bool vu_set_queue_host_notifier(VuDev *dev, VuVirtq
*vq, int fd,
return false;
}
+ pthread_mutex_lock(&dev->slave_mutex);
if (!vu_message_write(dev, dev->slave_fd, &vmsg)) {
+ pthread_mutex_unlock(&dev->slave_mutex);
return false;
}
+ /* Also unlocks the slave_mutex */
return vu_process_message_reply(dev, &vmsg);
}
@@ -1628,6 +1642,7 @@ vu_deinit(VuDev *dev)
close(dev->slave_fd);
dev->slave_fd = -1;
}
+ pthread_mutex_destroy(&dev->slave_mutex);
if (dev->sock != -1) {
close(dev->sock);
@@ -1663,6 +1678,7 @@ vu_init(VuDev *dev,
dev->remove_watch = remove_watch;
dev->iface = iface;
dev->log_call_fd = -1;
+ pthread_mutex_init(&dev->slave_mutex, NULL);
dev->slave_fd = -1;
dev->max_queues = max_queues;
diff --git a/contrib/libvhost-user/libvhost-user.h
b/contrib/libvhost-user/libvhost-user.h
index 46b600799b..1844b6f8d4 100644
--- a/contrib/libvhost-user/libvhost-user.h
+++ b/contrib/libvhost-user/libvhost-user.h
@@ -19,6 +19,7 @@
#include <stddef.h>
#include <sys/poll.h>
#include <linux/vhost.h>
+#include <pthread.h>
#include "standard-headers/linux/virtio_ring.h"
/* Based on qemu/hw/virtio/vhost-user.c */
@@ -355,6 +356,8 @@ struct VuDev {
VuVirtq *vq;
VuDevInflightInfo inflight_info;
int log_call_fd;
+ /* Must be held while using slave_fd */
+ pthread_mutex_t slave_mutex;
int slave_fd;
uint64_t log_size;
uint8_t *log_table;
--
2.24.1
- [PULL 056/111] virtiofsd: set maximum RLIMIT_NOFILE limit, (continued)
- [PULL 056/111] virtiofsd: set maximum RLIMIT_NOFILE limit, Dr. David Alan Gilbert (git), 2020/01/23
- [PULL 063/111] virtiofsd: Add timestamp to the log with FUSE_LOG_DEBUG level, Dr. David Alan Gilbert (git), 2020/01/23
- [PULL 061/111] virtiofsd: print log only when priority is high enough, Dr. David Alan Gilbert (git), 2020/01/23
- [PULL 062/111] virtiofsd: Add ID to the log with FUSE_LOG_DEBUG level, Dr. David Alan Gilbert (git), 2020/01/23
- [PULL 060/111] virtiofsd: add --syslog command-line option, Dr. David Alan Gilbert (git), 2020/01/23
- [PULL 064/111] virtiofsd: Handle reinit, Dr. David Alan Gilbert (git), 2020/01/23
- [PULL 065/111] virtiofsd: Handle hard reboot, Dr. David Alan Gilbert (git), 2020/01/23
- [PULL 066/111] virtiofsd: Kill threads when queues are stopped, Dr. David Alan Gilbert (git), 2020/01/23
- [PULL 070/111] virtiofsd: passthrough_ll: disable readdirplus on cache=never, Dr. David Alan Gilbert (git), 2020/01/23
- [PULL 069/111] virtiofsd: passthrough_ll: add renameat2 support, Dr. David Alan Gilbert (git), 2020/01/23
- [PULL 068/111] contrib/libvhost-user: Protect slave fd with mutex,
Dr. David Alan Gilbert (git) <=
- [PULL 072/111] virtiofsd: rename unref_inode() to unref_inode_lolocked(), Dr. David Alan Gilbert (git), 2020/01/23
- [PULL 067/111] vhost-user: Print unexpected slave message types, Dr. David Alan Gilbert (git), 2020/01/23
- [PULL 076/111] virtiofsd: passthrough_ll: use hashtable, Dr. David Alan Gilbert (git), 2020/01/23
- [PULL 073/111] virtiofsd: fail when parent inode isn't known in lo_do_lookup(), Dr. David Alan Gilbert (git), 2020/01/23
- [PULL 075/111] virtiofsd: passthrough_ll: clean up cache related options, Dr. David Alan Gilbert (git), 2020/01/23
- [PULL 077/111] virtiofsd: Clean up inodes on destroy, Dr. David Alan Gilbert (git), 2020/01/23
- [PULL 080/111] virtiofsd: cleanup allocated resource in se, Dr. David Alan Gilbert (git), 2020/01/23
- [PULL 081/111] virtiofsd: fix memory leak on lo.source, Dr. David Alan Gilbert (git), 2020/01/23
- [PULL 079/111] virtiofsd: fix error handling in main(), Dr. David Alan Gilbert (git), 2020/01/23
- [PULL 078/111] virtiofsd: support nanosecond resolution for file timestamp, Dr. David Alan Gilbert (git), 2020/01/23