We want to use tcm_vhost_mutex to make sure hotplug/hotunplug will not
happen when set_endpoint/clear_endpoint is in process.
Signed-off-by: Asias He <as...@redhat.com>
---
drivers/vhost/tcm_vhost.c | 32 +++++++++++++++++++-------------
1 file changed, 19 insertions(+), 13 deletions(-)
diff --git a/drivers/vhost/tcm_vhost.c b/drivers/vhost/tcm_vhost.c
index 957a0b9..822cd1f 100644
--- a/drivers/vhost/tcm_vhost.c
+++ b/drivers/vhost/tcm_vhost.c
@@ -808,6 +808,9 @@ static void vhost_scsi_flush(struct vhost_scsi *vs)
/*
* Called from vhost_scsi_ioctl() context to walk the list of available
* tcm_vhost_tpg with an active struct tcm_vhost_nexus
+ *
+ * The lock nesting rule is:
+ * tcm_vhost_mutex -> vs->dev.mutex -> tpg->tv_tpg_mutex -> vq->mutex
*/
static int vhost_scsi_set_endpoint(
struct vhost_scsi *vs,
@@ -820,26 +823,27 @@ static int vhost_scsi_set_endpoint(
int index, ret, i, len;
bool match = false;
+ mutex_lock(&tcm_vhost_mutex);
mutex_lock(&vs->dev.mutex);
+
/* Verify that ring has been setup correctly. */
for (index = 0; index < vs->dev.nvqs; ++index) {
/* Verify that ring has been setup correctly. */
if (!vhost_vq_access_ok(&vs->vqs[index])) {
- mutex_unlock(&vs->dev.mutex);
- return -EFAULT;
+ ret = -EFAULT;
+ goto out;
}
}
len = sizeof(vs_tpg[0]) * VHOST_SCSI_MAX_TARGET;
vs_tpg = kzalloc(len, GFP_KERNEL);
if (!vs_tpg) {
- mutex_unlock(&vs->dev.mutex);
- return -ENOMEM;
+ ret = -ENOMEM;
+ goto out;
}
if (vs->vs_tpg)
memcpy(vs_tpg, vs->vs_tpg, len);
- mutex_lock(&tcm_vhost_mutex);
list_for_each_entry(tv_tpg, &tcm_vhost_list, tv_tpg_list) {
mutex_lock(&tv_tpg->tv_tpg_mutex);
if (!tv_tpg->tpg_nexus) {
@@ -854,11 +858,10 @@ static int vhost_scsi_set_endpoint(
if (!strcmp(tv_tport->tport_name, t->vhost_wwpn)) {
if (vs->vs_tpg && vs->vs_tpg[tv_tpg->tport_tpgt]) {
- mutex_unlock(&tv_tpg->tv_tpg_mutex);
- mutex_unlock(&tcm_vhost_mutex);
- mutex_unlock(&vs->dev.mutex);
kfree(vs_tpg);
- return -EEXIST;
+ mutex_unlock(&tv_tpg->tv_tpg_mutex);
+ ret = -EEXIST;
+ goto out;
}
tv_tpg->tv_tpg_vhost_count++;
vs_tpg[tv_tpg->tport_tpgt] = tv_tpg;
@@ -867,7 +870,6 @@ static int vhost_scsi_set_endpoint(
}
mutex_unlock(&tv_tpg->tv_tpg_mutex);
}
- mutex_unlock(&tcm_vhost_mutex);
if (match) {
memcpy(vs->vs_vhost_wwpn, t->vhost_wwpn,
@@ -893,7 +895,9 @@ static int vhost_scsi_set_endpoint(
kfree(vs->vs_tpg);
vs->vs_tpg = vs_tpg;
+out:
mutex_unlock(&vs->dev.mutex);
+ mutex_unlock(&tcm_vhost_mutex);
return ret;
}
@@ -908,6 +912,7 @@ static int vhost_scsi_clear_endpoint(
int index, ret, i;
u8 target;
+ mutex_lock(&tcm_vhost_mutex);
mutex_lock(&vs->dev.mutex);
/* Verify that ring has been setup correctly. */
for (index = 0; index < vs->dev.nvqs; ++index) {
@@ -918,8 +923,8 @@ static int vhost_scsi_clear_endpoint(
}
if (!vs->vs_tpg) {
- mutex_unlock(&vs->dev.mutex);
- return 0;
+ ret = 0;
+ goto err_dev;
}
for (i = 0; i < VHOST_SCSI_MAX_TARGET; i++) {
@@ -965,13 +970,14 @@ static int vhost_scsi_clear_endpoint(
kfree(vs->vs_tpg);
vs->vs_tpg = NULL;
mutex_unlock(&vs->dev.mutex);
-
+ mutex_unlock(&tcm_vhost_mutex);
return 0;
err_tpg:
mutex_unlock(&tv_tpg->tv_tpg_mutex);
err_dev:
mutex_unlock(&vs->dev.mutex);
+ mutex_unlock(&tcm_vhost_mutex);
return ret;
}
--
1.8.1.4
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