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path: root/drivers/vhost/scsi.c
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Diffstat (limited to 'drivers/vhost/scsi.c')
-rw-r--r--drivers/vhost/scsi.c21
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);