Merge tag 'v5.2-rc5' into locking/core, to pick up fixes

Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 14 insertions, 7 deletions

diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
index c090d177bd75..a9caf1bc3c3e 100644
--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -57,6 +57,12 @@
 #define VHOST_SCSI_PREALLOC_UPAGES 2048
 #define VHOST_SCSI_PREALLOC_PROT_SGLS 2048
 
+/* Max number of requests before requeueing the job.
+ * Using this limit prevents one virtqueue from starving others with
+ * request.
+ */
+#define VHOST_SCSI_WEIGHT 256
+
 struct vhost_scsi_inflight {
         /* Wait for the flush operation to finish */
         struct completion comp;
@@ -912,7 +918,7 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
         struct iov_iter in_iter, prot_iter, data_iter;
         u64 tag;
         u32 exp_data_len, data_direction;
-        int ret, prot_bytes;
+        int ret, prot_bytes, c = 0;
         u16 lun;
         u8 task_attr;
         bool t10_pi = vhost_has_feature(vq, VIRTIO_SCSI_F_T10_PI);
@@ -932,7 +938,7 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
 
         vhost_disable_notify(&vs->dev, vq);
 
-        for (;;) {
+        do {
                 ret = vhost_scsi_get_desc(vs, vq, &vc);
                 if (ret)
                         goto err;
@@ -1112,7 +1118,7 @@ err:
                         break;
                 else if (ret == -EIO)
                         vhost_scsi_send_bad_target(vs, vq, vc.head, vc.out);
-        }
+        } while (likely(!vhost_exceeds_weight(vq, ++c, 0)));
 out:
         mutex_unlock(&vq->mutex);
 }
@@ -1171,7 +1177,7 @@ vhost_scsi_ctl_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
         } v_req;
         struct vhost_scsi_ctx vc;
         size_t typ_size;
-        int ret;
+        int ret, c = 0;
 
         mutex_lock(&vq->mutex);
         /*
@@ -1185,7 +1191,7 @@ vhost_scsi_ctl_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
 
         vhost_disable_notify(&vs->dev, vq);
 
-        for (;;) {
+        do {
                 ret = vhost_scsi_get_desc(vs, vq, &vc);
                 if (ret)
                         goto err;
@@ -1264,7 +1270,7 @@ err:
                         break;
                 else if (ret == -EIO)
                         vhost_scsi_send_bad_target(vs, vq, vc.head, vc.out);
-        }
+        } while (likely(!vhost_exceeds_weight(vq, ++c, 0)));
 out:
         mutex_unlock(&vq->mutex);
 }
@@ -1621,7 +1627,8 @@ static int vhost_scsi_open(struct inode *inode, struct file *f)
                 vqs[i] = &vs->vqs[i].vq;
                 vs->vqs[i].vq.handle_kick = vhost_scsi_handle_kick;
         }
-        vhost_dev_init(&vs->dev, vqs, VHOST_SCSI_MAX_VQ, UIO_MAXIOV);
+        vhost_dev_init(&vs->dev, vqs, VHOST_SCSI_MAX_VQ, UIO_MAXIOV,
+                       VHOST_SCSI_WEIGHT, 0);
 
         vhost_scsi_init_inflight(vs, NULL);