[PATCH 063/104] virtiofsd: Kill threads when queues are stopped

[Dr. David Alan Gilbert (git)]

From: "Dr. David Alan Gilbert" <address@hidden>

Kill the threads we've started when the queues get stopped.

Signed-off-by: Dr. David Alan Gilbert <address@hidden>
---
 tools/virtiofsd/fuse_virtio.c | 37 +++++++++++++++++++++++++++++++----
 1 file changed, 33 insertions(+), 4 deletions(-)

diff --git a/tools/virtiofsd/fuse_virtio.c b/tools/virtiofsd/fuse_virtio.c
index 3c778b6296..2f11fee46d 100644
--- a/tools/virtiofsd/fuse_virtio.c
+++ b/tools/virtiofsd/fuse_virtio.c
@@ -41,6 +41,7 @@ struct fv_QueueInfo {
     /* Our queue index, corresponds to array position */
     int qidx;
     int kick_fd;
+    int kill_fd; /* For killing the thread */
 
     /* The element for the command currently being processed */
     VuVirtqElement *qe;
@@ -410,14 +411,17 @@ static void *fv_queue_thread(void *opaque)
     fuse_log(FUSE_LOG_INFO, "%s: Start for queue %d kick_fd %d\n", __func__,
              qi->qidx, qi->kick_fd);
     while (1) {
-        struct pollfd pf[1];
+        struct pollfd pf[2];
         pf[0].fd = qi->kick_fd;
         pf[0].events = POLLIN;
         pf[0].revents = 0;
+        pf[1].fd = qi->kill_fd;
+        pf[1].events = POLLIN;
+        pf[1].revents = 0;
 
         fuse_log(FUSE_LOG_DEBUG, "%s: Waiting for Queue %d event\n", __func__,
                  qi->qidx);
-        int poll_res = ppoll(pf, 1, NULL, NULL);
+        int poll_res = ppoll(pf, 2, NULL, NULL);
 
         if (poll_res == -1) {
             if (errno == EINTR) {
@@ -428,12 +432,23 @@ static void *fv_queue_thread(void *opaque)
             fuse_log(FUSE_LOG_ERR, "fv_queue_thread ppoll: %m\n");
             break;
         }
-        assert(poll_res == 1);
+        assert(poll_res >= 1);
         if (pf[0].revents & (POLLERR | POLLHUP | POLLNVAL)) {
             fuse_log(FUSE_LOG_ERR, "%s: Unexpected poll revents %x Queue %d\n",
                      __func__, pf[0].revents, qi->qidx);
             break;
         }
+        if (pf[1].revents & (POLLERR | POLLHUP | POLLNVAL)) {
+            fuse_log(FUSE_LOG_ERR,
+                     "%s: Unexpected poll revents %x Queue %d killfd\n",
+                     __func__, pf[1].revents, qi->qidx);
+            break;
+        }
+        if (pf[1].revents) {
+            fuse_log(FUSE_LOG_INFO, "%s: kill event on queue %d - quitting\n",
+                     __func__, qi->qidx);
+            break;
+        }
         assert(pf[0].revents & POLLIN);
         fuse_log(FUSE_LOG_DEBUG, "%s: Got queue event on Queue %d\n", __func__,
                  qi->qidx);
@@ -631,15 +646,29 @@ static void fv_queue_set_started(VuDev *dev, int qidx, 
bool started)
         }
         ourqi = vud->qi[qidx];
         ourqi->kick_fd = dev->vq[qidx].kick_fd;
+
+        ourqi->kill_fd = eventfd(0, EFD_CLOEXEC | EFD_SEMAPHORE);
+        assert(ourqi->kill_fd != -1);
         if (pthread_create(&ourqi->thread, NULL, fv_queue_thread, ourqi)) {
             fuse_log(FUSE_LOG_ERR, "%s: Failed to create thread for queue 
%d\n",
                      __func__, qidx);
             assert(0);
         }
     } else {
-        /* TODO: Kill the thread */
+        int ret;
         assert(qidx < vud->nqueues);
         ourqi = vud->qi[qidx];
+
+        /* Kill the thread */
+        if (eventfd_write(ourqi->kill_fd, 1)) {
+            fuse_log(FUSE_LOG_ERR, "Eventfd_read for queue: %m\n");
+        }
+        ret = pthread_join(ourqi->thread, NULL);
+        if (ret) {
+            fuse_log(FUSE_LOG_ERR, "%s: Failed to join thread idx %d err %d\n",
+                     __func__, qidx, ret);
+        }
+        close(ourqi->kill_fd);
         ourqi->kick_fd = -1;
     }
 }
-- 
2.23.0