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authorVivek Goyal <vgoyal@redhat.com>2019-10-30 18:07:19 +0300
committerMiklos Szeredi <mszeredi@redhat.com>2019-11-22 15:29:50 +0300
commit724c15a43e2c7ac26e2d07abef99191162498fa9 (patch)
treea542c172aa1b890341b2bfc99d853067c0db8887 /fs/fuse
parent1efcf39eb627573f8d543ea396cf36b0651b1e56 (diff)
downloadlinux-724c15a43e2c7ac26e2d07abef99191162498fa9.tar.xz
virtiofs: Use completions while waiting for queue to be drained
While we wait for queue to finish draining, use completions instead of usleep_range(). This is better way of waiting for event. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Diffstat (limited to 'fs/fuse')
-rw-r--r--fs/fuse/virtio_fs.c39
1 files changed, 29 insertions, 10 deletions
diff --git a/fs/fuse/virtio_fs.c b/fs/fuse/virtio_fs.c
index da603e0cbd0d..bade74768903 100644
--- a/fs/fuse/virtio_fs.c
+++ b/fs/fuse/virtio_fs.c
@@ -35,6 +35,7 @@ struct virtio_fs_vq {
struct fuse_dev *fud;
bool connected;
long in_flight;
+ struct completion in_flight_zero; /* No inflight requests */
char name[24];
} ____cacheline_aligned_in_smp;
@@ -85,6 +86,8 @@ static inline void dec_in_flight_req(struct virtio_fs_vq *fsvq)
{
WARN_ON(fsvq->in_flight <= 0);
fsvq->in_flight--;
+ if (!fsvq->in_flight)
+ complete(&fsvq->in_flight_zero);
}
static void release_virtio_fs_obj(struct kref *ref)
@@ -115,22 +118,23 @@ static void virtio_fs_drain_queue(struct virtio_fs_vq *fsvq)
WARN_ON(fsvq->in_flight < 0);
/* Wait for in flight requests to finish.*/
- while (1) {
- spin_lock(&fsvq->lock);
- if (!fsvq->in_flight) {
- spin_unlock(&fsvq->lock);
- break;
- }
+ spin_lock(&fsvq->lock);
+ if (fsvq->in_flight) {
+ /* We are holding virtio_fs_mutex. There should not be any
+ * waiters waiting for completion.
+ */
+ reinit_completion(&fsvq->in_flight_zero);
+ spin_unlock(&fsvq->lock);
+ wait_for_completion(&fsvq->in_flight_zero);
+ } else {
spin_unlock(&fsvq->lock);
- /* TODO use completion instead of timeout */
- usleep_range(1000, 2000);
}
flush_work(&fsvq->done_work);
flush_delayed_work(&fsvq->dispatch_work);
}
-static void virtio_fs_drain_all_queues(struct virtio_fs *fs)
+static void virtio_fs_drain_all_queues_locked(struct virtio_fs *fs)
{
struct virtio_fs_vq *fsvq;
int i;
@@ -141,6 +145,19 @@ static void virtio_fs_drain_all_queues(struct virtio_fs *fs)
}
}
+static void virtio_fs_drain_all_queues(struct virtio_fs *fs)
+{
+ /* Provides mutual exclusion between ->remove and ->kill_sb
+ * paths. We don't want both of these draining queue at the
+ * same time. Current completion logic reinits completion
+ * and that means there should not be any other thread
+ * doing reinit or waiting for completion already.
+ */
+ mutex_lock(&virtio_fs_mutex);
+ virtio_fs_drain_all_queues_locked(fs);
+ mutex_unlock(&virtio_fs_mutex);
+}
+
static void virtio_fs_start_all_queues(struct virtio_fs *fs)
{
struct virtio_fs_vq *fsvq;
@@ -581,6 +598,7 @@ static int virtio_fs_setup_vqs(struct virtio_device *vdev,
INIT_LIST_HEAD(&fs->vqs[VQ_HIPRIO].end_reqs);
INIT_DELAYED_WORK(&fs->vqs[VQ_HIPRIO].dispatch_work,
virtio_fs_hiprio_dispatch_work);
+ init_completion(&fs->vqs[VQ_HIPRIO].in_flight_zero);
spin_lock_init(&fs->vqs[VQ_HIPRIO].lock);
/* Initialize the requests virtqueues */
@@ -591,6 +609,7 @@ static int virtio_fs_setup_vqs(struct virtio_device *vdev,
virtio_fs_request_dispatch_work);
INIT_LIST_HEAD(&fs->vqs[i].queued_reqs);
INIT_LIST_HEAD(&fs->vqs[i].end_reqs);
+ init_completion(&fs->vqs[i].in_flight_zero);
snprintf(fs->vqs[i].name, sizeof(fs->vqs[i].name),
"requests.%u", i - VQ_REQUEST);
callbacks[i] = virtio_fs_vq_done;
@@ -684,7 +703,7 @@ static void virtio_fs_remove(struct virtio_device *vdev)
/* This device is going away. No one should get new reference */
list_del_init(&fs->list);
virtio_fs_stop_all_queues(fs);
- virtio_fs_drain_all_queues(fs);
+ virtio_fs_drain_all_queues_locked(fs);
vdev->config->reset(vdev);
virtio_fs_cleanup_vqs(vdev, fs);