@@ -1540,7 +1540,7 @@ static int vhost_scsi_setup_vq_cmds(struct vhost_virtqueue *vq, int max_cmds)
* vhost_scsi_tpg with an active struct vhost_scsi_nexus
*
* The lock nesting rule is:
- * vhost_scsi_mutex -> vs->dev.mutex -> tpg->tv_tpg_mutex -> vq->mutex
+ * vs->dev.mutex -> vhost_scsi_mutex -> tpg->tv_tpg_mutex -> vq->mutex
*/
static int
vhost_scsi_set_endpoint(struct vhost_scsi *vs,
@@ -1554,7 +1554,6 @@ vhost_scsi_set_endpoint(struct vhost_scsi *vs,
int index, ret, i, len;
bool match = false;
- mutex_lock(&vhost_scsi_mutex);
mutex_lock(&vs->dev.mutex);
/* Verify that ring has been setup correctly. */
@@ -1575,6 +1574,7 @@ vhost_scsi_set_endpoint(struct vhost_scsi *vs,
if (vs->vs_tpg)
memcpy(vs_tpg, vs->vs_tpg, len);
+ mutex_lock(&vhost_scsi_mutex);
list_for_each_entry(tpg, &vhost_scsi_list, tv_tpg_list) {
mutex_lock(&tpg->tv_tpg_mutex);
if (!tpg->tpg_nexus) {
@@ -1590,6 +1590,7 @@ vhost_scsi_set_endpoint(struct vhost_scsi *vs,
if (!strcmp(tv_tport->tport_name, t->vhost_wwpn)) {
if (vs->vs_tpg && vs->vs_tpg[tpg->tport_tpgt]) {
mutex_unlock(&tpg->tv_tpg_mutex);
+ mutex_unlock(&vhost_scsi_mutex);
ret = -EEXIST;
goto undepend;
}
@@ -1604,6 +1605,7 @@ vhost_scsi_set_endpoint(struct vhost_scsi *vs,
if (ret) {
pr_warn("target_depend_item() failed: %d\n", ret);
mutex_unlock(&tpg->tv_tpg_mutex);
+ mutex_unlock(&vhost_scsi_mutex);
goto undepend;
}
tpg->tv_tpg_vhost_count++;
@@ -1613,6 +1615,7 @@ vhost_scsi_set_endpoint(struct vhost_scsi *vs,
}
mutex_unlock(&tpg->tv_tpg_mutex);
}
+ mutex_unlock(&vhost_scsi_mutex);
if (match) {
memcpy(vs->vs_vhost_wwpn, t->vhost_wwpn,
@@ -1667,7 +1670,6 @@ vhost_scsi_set_endpoint(struct vhost_scsi *vs,
kfree(vs_tpg);
out:
mutex_unlock(&vs->dev.mutex);
- mutex_unlock(&vhost_scsi_mutex);
return ret;
}
@@ -1683,7 +1685,6 @@ vhost_scsi_clear_endpoint(struct vhost_scsi *vs,
int index, ret, i;
u8 target;
- mutex_lock(&vhost_scsi_mutex);
mutex_lock(&vs->dev.mutex);
/* Verify that ring has been setup correctly. */
for (index = 0; index < vs->dev.nvqs; ++index) {
@@ -1765,12 +1766,10 @@ vhost_scsi_clear_endpoint(struct vhost_scsi *vs,
vs->vs_tpg = NULL;
WARN_ON(vs->vs_events_nr);
mutex_unlock(&vs->dev.mutex);
- mutex_unlock(&vhost_scsi_mutex);
return 0;
err_dev:
mutex_unlock(&vs->dev.mutex);
- mutex_unlock(&vhost_scsi_mutex);
return ret;
}
Now that vhost_scsi_clear_endpoint will prevent new IO and flush running IO before dropping it's refcounts on the tpg, we only need to hold the vhost_scsi_mutex while looping over tpgs and taking a refcount, and when manipulating the tpg list. This removes the vhost_scsi_mutex from vhost_scsi_clear_endpoint and moves the vhost_scsi_mutex use in vhost_scsi_set_endpoint so it's only taken while looping over the tpgs and taking a refcount. We can then now avoid issues where vhost_scsi_set_endpoint has to wait for another device's vhost_scsi_clear_endpoint call. Signed-off-by: Mike Christie <michael.christie@oracle.com> --- drivers/vhost/scsi.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-)